CDNA05561ENC_001

VOL. 1 NO. 2, 3 OCTOBER 1976 PUBLISHED QUARTERLY

SPECIAL ISSUE

THE MAIZE CROP * -#6 A BASIC FEED■-.--.- -FOR BEEF PRODUCTION

ANIMAL FEED SCIENCE AND TECHNOLOGY

An International Journal

Elsevier

ANIMAL FEED SCIENCE AND TECHNOLOGY An International Scientific Journal

EDITOR-IN-CHIEF: J.F.D. Greenhalgh, Rowett Research Institute, Bucksburn, Aberdeen, Great Britain

EDITORIAL ADVISORY BOARD:

R.W. Bailey, Palmerston North, New Zealand J.R. Brethour, Hays, Kans., U.S.A. F.X. Buysse, Gontrode, Belgium J.L. Corbett, Armidale, N.S.W., Australia W.W. Cravens, Fort Wayne, Ind., U.S.A. J. Dammers, Wormerveer, The Netherlands E. Donefer, St. Anne de Bellevue, Que., Canada M.G. Jackson, Pantnagar, India M. Kirchgessner, Freising-Weihenstephan,

Federal Republic of Germany

E. Knobloch, Prague, Czechoslovakia J.K. Loosli, Ithaca, N.Y., U.S.A. D.J. Minson, Brisbane, Qld., Australia A. Schüren, Zür ich, Switzerland P. Sonne-Frederiksen, Kolding, Denmark A.J.H. Van Es, Hoorn, The Netherlands P.J. Van Soest, Ithaca, N.Y., U.S.A. R.J. Wilkins, Hurley, Great Britain

GENERAL INFORMATION

Aims and Scope. Animal Feed Science and Technology is primarily concerned wi th the publication of scientific papers dealing wi th the production, composition and nutrit ive value of feeds for animals. A t the same time it is intended to only treat matter which is of relevance to an ¡nternational readership. The journal wi l l cover such areas as the nutritive value of feeds (assessment, improvement, etc.), methods of conserving, processing and manufacturing feeds, uti l ization of feeds and the improvement of such, and the environmental effects of feeds (resultant toxici ty of animal products for man, re-cycling, etc.). I t is intended to attract readers from the disciplines of both crop and animal science, f rom the professions of research, teaching and advisory work, and from the industries of agriculture and feed manufacturing.

Publication schedule. Animal Feed Science and Technology appears quarterly; volume 1 (4 issues): 1976.

Submission of articles. Manuscripts should be submitted in triplicate to the Editorial Office of Animal Feed Science and Technology, P.O. Box 330, Amsterdam, The Netherlands.

Subscriptions. Subscription price for Volume 1 is Df l . 107.00 including postage and handling. Send your order to your usual supplier or direct to Associated Scientific Publishers, Journal Division, P.O. Box 211 , Amsterdam, The Netherlands.

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Amazon Jungle: GreenHellTbRed Desert? An Ecological Discussion of the Environmental Impact of the Highway Con­struction Program in the Amazon Basin.

by ROBERT J.A. GOODLAND, Ecologist, The Cary Arboretum of the New York Botanical Garden, and HOWARD S. IRWIN, President, The New York Botanical Garden; Director, The Cary Arboretum of the New York Botanical Garden.

DEVELOPMENTS IN LANDSCAPE MANAGEMENT AND URBAN PLANNING, 1 Reprinted from the journal Landscape Planning, Vol. 1, No. 2/3

1975. X + 155 pages. US $13.75/Dfl. 33.00. ISBN 0-444-41318-9

The largest of the remaining natural areas left on this planet is the vast Amazon region with its great yet extremely fragile equatorial rain-forest ecosystem - the "hylaea". The Amazonian Amerindian, divided into many sub-groups or tribes, has had the astonishing ability to persist and thrive in that ecosystem for many thousands of years without destroying it. This book summarizes and evaluates what is known about Amazonia - its history, biota, ecology, ethnology, and the repercussions of human interactions with the ecosystem. It demonstrates the unavoidable consequences of the highway network (one of which is subse­quent large-scale deforestation), and discusses the likely environmental results of the large-scale cattle ranching and agriculture along these highways. Readers will readily perceive and understand that all of the authors' warnings, criticisms, and estimates of future prospects are nothing less than an entreaty to stop the irreparable de­struction of a life-filled area, with its multitude of irreplaceable forms of plant and animal life, its exquisite biotic communities, and the last survivors of a unique and once great human culture.

CONTENTS: Preface (H. Sioli). Introduction. The routes of the major highways. Characteristics of the highway. Justification of the highways. History of the Development of Amazonia. History. Chronology of events concerning Amazonia. Deforestation and Agriculture. Agricultural colonization policies. The lowland tropical wet forest ecosystem. The 50% forest rule. The decline in crop yields. Meteorological impact. Alternatives to present trends. Human Ecology and Nosogeography. Diseases and the highway. Remediation. Amerindians. Amerindians of Amazonia. Amerindians affected by the highways. Improving Amerindian future. Decree gov­erning the National Xingu Park. Fauna and Faunatlon. Value of the fauna. Composition of the fauna. Flora and Vegetation (after G.T. Prance). Physiognomic types. Summary of Amazonian vegetation types. Undiscovered species. Species extinction by exploitation. Regen­eration of forest Industry. Hydroelectricity. South American "great lakes" system. Iron. Aluminium. Manganese. Cassiterite. Rio Jaro development. Conclusion. Guide to the literature. Acknowledgements. List of Acronyms. References. Index. The Authors.

ELSEVIER SCIENTIFIC PUBLISHING COMPANY P.O. Box 211, Amsterdam, The Netherlands Distributed in the U.S.A. and Canada by: AMERICAN ELSEVIER PUBLISHING COMPANY 52 Vanderbilt Ave., New York, N.Y. 10017 Prices are subiect to change without prior notice.

1752 E

LANDSCAPE PLANNING An International Journal on Landscape Ecology, Reclamation and Conser­vation, Outdoor Recreation and Land-Use Management.

Editor- in-Chief : A.E. WEDDLE, University of Sheffield, Dept. of Landscape Architec­ture, Shef f ie ld, Great Br i ta in.

Subscription Information: 1976 - Volume 3 (in 4 issues) US $39.95/Dfl . 100.00 including postage.

Vol. 1, No. 1: Editorial: Landscape Planning - aims and scope of a new journal (A.E Weddle). Unity and diversity in landscape (S.P. Tjallingii). Changing scenic values and tourist carrying capacity of national parks. An Australian example (J.D. Ovington, K.W. Groves, P.R. Stevens and M.T. Tanton). Art, science, technology, democracy and the landscape (G. Eckbo). The engineering landscape in an historical area of Central Europe (V. Vanitek and A. Hrabal). Vegetation burning and forest reservation in a segment of the forest - savanna mosaic of Nigeria: a preliminary investigation (M.U. Igbozurike).

Vol.1. Nos. 2/3: An ecological discussion of the environmental impact of the highway const ruction program in the Amazon Basin (R.J.A. Goodland and H.S. Irwin). Trees on building sites (A. Bernatzky). Environmental analysis of quarrying: an Israeli experience (R. Enis and M. Shechter).

Vol. 1, No. 4: Apprasial of visual landscape qualities in a region selected for accelerated growth (G. Wright). Microclimate and recreational value of tree plantings in deserts (G. Schiller and R. Karschon). A philosophical approach to landscape planning (G.A. Hills).

Vol. 2, No. 1 ¡Problems and objectives of landscape architecture and landscape planning in the German Democratic Republic (H. Linke and S. Thomas). Future opportunities for open space (M.D. Bradley). The accuracy of map overlays (E.B. MacDougall). Recommendations for a new Spanish Institute of Environmental Analysis (M.G. de Viedma, D. Bevan, A.E. Weddle and A. Ramos). Ecological landscape inventories and evaluation (G. Olschowy). Planning for water recreation in Israel (V. Kenyon and R. Enis).

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5330 E

93

ANIMAL FEED SCIENCE AND TECHNOLOGY

An In te rna t iona l Journal

Special Issue

THE MAIZE CROP AS A BASIC FEED FOR BEEF PRODUCTION

Edited by

J.C. TAYLER and J.M. WILKINSON

The Grassland Research Institute, Hurley, Maidenhead, United Kingdom

AN INTERNATIONAL WORKING CONFERENCE in the EEC Programme of Co-ordination of Research on Beef Production

Held at the

Livestock Research Institute, Veljka Vlahovića 2, PO Box 82, 21000 NOVI SAD. Yugoslavia

June 21 - 25, 1976

Sponsored by the

COMMISSION OF THE EUROPEAN COMMUNITIES. DIRECTORATE-GENERAL FOR AGRICULTURE Division for the Co-ordination of Agricultural Research

r 3%0£B UH??,

94

Publication arranged by

The Commission of the European Communities, Directorate-General for Scientific and Technical Information and Information Management, European Centre, Kirchberg, Luxembourg.

© ECSC, EEC, EAEC, Luxembourg 1976

LEGAL NOTICE

Neither the Commission of the European Communities nor any person acting on behalf of the Commission is responsible for the use which might be made of the following information

95

CONTENTS

Preface 99 Objectives and Background to Seminar 100 Opening Remarks 101

SESSION 1 SURVEY OF THE USE OF MAIZE FOR LIVESTOCK FEEDING IN EACH COUNTRY 107

Southern Regions SURVEY OF THE MAIZE SITUATION IN ITALY 109 A. Romita REVIEW OF PRODUCTION AND UTILISATION OF MAIZE FOR ANIMAL NUTRITION IN YUGOSLAVIA 115 A. Sreckovic USE OF MAIZE FOR RUMINANTS AND PIG FEEDING IN GREECE 125 D. Mergounis SURVEY OF THE USE OF MAIZE FOR LIVESTOCK FEEDING IN SPAIN 129 G. Gonzalez and A. Monteagudo SURVEY OF THE USE OF MAIZE FOR LIVESTOCK FEEDING IN PORTUGAL 137 J.5. Da Costa Southern to Northern Continental Regions MAIZE AND ANIMAL PRODUCTION IN FRANCE 141 C. Lelong SURVEY OF THE USE OF MAIZE FOR LIVESTOCK FEEDING IN SWITZERLAND '4? H. Schneeberger SURVEY OF THE USE OF MAIZE FOR LIVESTOCK FEEDING IN AUSTRIA 153 B. Laber USE OF MAIZE FOR LIVESTOCK FEEDING IN GERMANY (FED. REP.). 157 E. Zimmer and J. Zscheischler SURVEY OF THE USE OF MAIZE FOR LIVESTOCK FEEDING IN BELGIUM 167 B.G. Cottyn, Ch. V. Boucqué and F.X. Buysse USE OF MAIZE FOR LIVESTOCK FEEDING IN THE NETHERLANDS 177 F. de Boer Northern Regions MAIZE AS A FORAGE CROP IN DENMARK 183 Kr. G. MiSlle PROSPECTS OF GROWING MAIZE IN FINLAND 187 Seppo Pulii, Esko Poutiainen and Liisa Syrjälä THE CURRENT SITUATION REGARDING THE USE OF MAIZE IN IRELAND 195 F.J. Harte THE USE OF MAIZE FOR LIVESTOCK FEEDING IN THE UNITED KINGDOM 199 J.B. Kilkenny DISCUSSION ON SESSION 1 215

96

SESSION II THE EFFECT OF AGRONOMIC FACTORS ON THE YIELD AND COMPOSITION OF THE MAIZE CROP, CONSIDERED IN RE­LATION TO THE METHOD OF USE OF THE CROP 227

Southern Regions - non-irrigated THE USE OF TECHNIQUES OF MAIZE CULTIVATION TO MAXIMISE FEED FOR BEEF PRODUCTION 229 R. Savie Southern Regions - irrigated CULTIVATION OF MAIZE IN IRRIGATED AREAS FDR SILAGE AND GRAIN PRODUCTION AND THEIR USE BY RUMINANTS 237 A. Monteagudo SELECTION OBJECTIVES FOR MAXIMUM YIELDS DF FEED WITH HYBRID MAIZE 245 J.L. Blanco Northern Regions EFFFCT OF AGRONOMIC FACTORS ON THE YIELD DF MAIZE AND ON ITS ' COMPOSITION IN RELATION TO ITS USE BY RUMINANTS 251 R.H. Phipps and R.F. Weiler Central Regions AGRONOMIC FACTORS AFFECTING THE GROWTH AMD COMPOSITION OF THE MAIZE PLANT 263 J. Andrieu DISCUSSION ON SESSION II 273

SESSION III EFFICIENCY OF HARVESTING AND CONSERVATION 287 EFFICIENCY OF HARVESTING AND CONSERVATION 289 E. Zimmer INFLUENCE OF ENSILING MAIZE EARS AND GRAIN ON CHEMICAL COMPOSITION, CONSERVATION LOSSES AND DIGESTIBILITY 301 R. Parigi-Bini and G.M. Chiericato EFFECT OF MAIZE SILAGE HARVEST STAGE DN YIELD, PLANT COMPOSITION AND FERMENTATION LOSSES 313 A. Giardini, F. Gaspari, M. Vecchiettini and P. Schenoni DISCUSSION ON SESSION III 327

SESSION IV NUTRITIVE VALUE FDR BEEF CATTLE OF DIETS BASED ON THE MAIZE CROP 345

ta) Effects of type of diet on energy intake and growth rate

MAIZE SILAGE WITH OR WITHOUT NPN, DEHYDRATED WHOLE-CROP MAIZF PELLETS OR HIGH-MOISTURE MAIZE GRAIN FOR FINISHING BULLS 347 Ch. V. Boucqué, B.G. Cottyn and F.X. Buysse ENERGY SUPPLEMENTATION OF MAIZE SILAGE HARVESTED AT DIFFERENT MATURITY STAGES 369 A. Giardini, M. Vecchiettini and A. Lo Bruno FACTORS INFLUENCING THE COMPOSITION AND NUTRITIVE VALUE OF ENSILED WHOLE-CROP MAIZE 381 J. Andrieu

97

MAIZE GRAIN OR EARS IN CONCENTRATE DIETS FOR YOUNG FATTENING BULLS 393 S. Bacvanski

RATE OF GROWTH. FEED UTILISATION AND DIGESTIBILITY OBSERVED WITH DIETS CONTAINING ENSILED MAIZE GRAIN OR MAIZE EARS FED ALONE OR IN MIXTURES 401 D. Lanari and M. Rioni

UTILISING THE MAIZE CROP IN VARIOUS FORMS FOR BEEF PRODUCTION 417 C. Malterre and C. Lelong

NUTRITIVE VALUE OF DEHYDRATED WHOLE-CROP MAIZE 429 Y. Geay and C. MaltBrre

VOLUNTARY INTAKE AND EFFICIENCY OF UTILISATION OF WHOLE-CROP MAIZE SILAGE 441 J.M. Wilkinson

(b) Nitrogen metabolism and research techniques

THE DIGESTION AND METABOLISM OF THE ENERGY AND PROTEIN OF MAIZE 455 D. E. Beever

LEVELS, SOURCES AND METHODS OF NITROGEN SUPPLEMENTATION OF MAIZE SILAGE FOR BEEF PRODUCTION 465 A. Giardini, F. Lambertini, F. Gaspari, and A. Lo Bruno

te) Utilisation of dietary energy

THE NUTRITIVE VALUE (ENERGY) OF MAIZE SILAGE 481 A.J.H. van Es, Y. van der Honing and H.A. Boekholt DISCUSSION ON SESSION IV 485

SESSION V SYSTEMS OF PRODUCTION AND EFFICIENCY OF USE OF RESOURCES 503 (a) Systems of bull-beef production from the maize crop

EFFECT OF WEIGHT AT SLAUGHTER ON THE EFFICIENCY OF FATTENING YOUNG CATTLE 505 T. Cobic

ECONOMIC ASPECTS OF HIGH-PLANE FEEDING OF BULLS WITH MAIZE SILAGE 513 K. Walter

FOR BEEF CATTLE ALL FORMS OF MAIZE CAN BE USED 521 C. Lelong

BULL-BEEF PRODUCTION FROM THE MAIZE CROP IN ITALY IN LARGE AND SMALL UNITS 531 M. Rioni and D. Lanari

DISCUSSION ON SESSION V 545

98

SESSION VI REQUIREMENTS FOR FUTURE RESEARCH 553

DISCUSSION LEADERS AND RECORDERS:

A. AGRONOMY, HARVESTING AND CONSERVATION A. Monteagudo and E. Zimmer

Β. NUTRITIVE VALUE, NITROGEN METABOLISM AND RESEARCH TECHNIQUES T. Cobic and R.J. Wilkins

C. SYSTEMS AND ECONOMICS K. Walter and A. Sreckovic

APPENDIX 1 Participants who provided details of research given in Appendix II 581

APPENDIX II Current national programmes of research in beef production from the maize crop 583

APPENDIX III List of participants 597

This special issue of Animal Feed Science and Technology was typeset for the Commission of the European Communities by Janssen Services, London. The style therefore differs in some respects from that normally used by the Elsevier Scientific Publishing Company. In particular, the shorter papers do not include an abstract.

99 PREFACE

This publication contains the Proceedings of an International Working Conference on current research and the direction of future research on the maize crop as a basic feed for beef pro­duction .

It was held in Yugoslavia on June 21st - 25th, 1976, under the auspices of the Commission of the European Communities, as part of the EEC programme of co-ordination of research on beef production.

This was the first conference on agricultural research in which the neighbouring countries of the Community in the COST group were invited to participate. COST (The Committee of Senior Officials on Scientific and Technical Research) was set up to examine means of improving co-operation and co-ordination of science and technology between the Community and third countries. The countries concerned in addition to the nine in the EEC are Austria, Finland, Greece, Norway, Portugal, Spain, Sweden, Switzerland, Turkey and Yugoslavia.

Certain proposals for concerted action on agricultural research were put to COST by Yugoslavia. The International Working Conference reported here forms a link between the existing Community programme of common and co-ordinated research and certain of the proposals on the use of the maize crop which were put forward by Yugoslavia.

The programme for the Conference was drawn up by a scien­tific working group comprising Dr. J.C. Tayler (Chairman, temp­orarily seconded to CEC during 1975); Dr. A. Sreckovic, Yugoslavia; Dr. T. Cobic, Yugoslavia; Dr. H. Honig, Germany (Fed. Rep.); Dr. D. Lanari, Italy; Professor A. Romita,Italy; Professor G. Gonzalez, Spain; Dr. A. Monteagudo, Spain; Dr. J.M. Wilkinson, United Kingdom; Mr. R. Jarrige, France; Mr. C. Béranger, France; Dr. Vaz, Portugal and Mr. P. L'Hermite, CEC.

The Commission wishes to thank the local organisers, Dr. A. Sreckovic and Dr. T. Cobic, Livestock Research Institute, Novi Sad and their colleagues for their work before and during the Conference.

100

OBJECTIVES

To examine current practice in the feeding of maize to live­stock; to discuss the results of recent research on the utilis­ation of the maize crop for beef production in relation to output per head and per ha and to the efficiency of use of energy em­ployed in growing, harvesting and feeding the crop; to consider how far the application of research could improve efficiency of utilisation of the crop in practice, including reference to eco­nomic aspects; and to discuss the needs for further research.

BACKGROUND

The area of maize grown for feeding to cattle is high in many countries and is increasing rapidly in others. In practice the whole crop may be fed, in fresh, dehydrated or ensiled form or the ear may be harvested and fed in different forms, with or without utilisation of the stover. Widely varying amounts of protein and energy supplements are fed with maize silage and this can affect output of beef per head and per ha. Problems requiring research arise in seeking to minimise the input of protein and energy supplements and to replace these with non­protein nitrogen ("PN) and to increase voluntary intake, which limits the use of maize as silage. There also may be interactions between geno­type, sex or age of animal, and the type of maize diet.

■ Efficiency can be considered in relation to land or crop use; the energy used in growing and feeding the crop; the intake and utilisation of nutrients by the animal; and in economic terms. ? definition of research objectives would need to take account of factors which lead to maximum efficiency of use of specified resources per unit of beef produced.

101 OPENING REMARKS

Dr. A. Sreckovic

Mr. Secretary Ilic, Mr. Director Craps, ladies and gentlemen, dear guests, it is a very great pleasure and honour to welcome all of you and especially our foreign guests to this International Working Conference on Current Research and the Direction of Future Research on the Maize Crop as a Basic Feed for Beef Production. We hope you will find the arrangements for your participation to your liking and the progamme itself profitable to you. The objective of this conference is to examine current research and practice in growing and utilisation of maize in modern industrial and profitable beef production.

We hope that the results of this conference will be of great benefit both for the organisers and each participating country as well. Therefore we expect your active participation in this conference.

Ladies and gentlemen, it is my great pleasure to present Mr. Petar Ilic, Vice Secretary of Agriculture of the Executive Council of Vojvodina who will extend the official welcome.

Mr. Petar Ilic

Ladies and gentlemen, in the name of the Federal Committee of Agriculture, the Exective Council of the Assembly of Autonomous Province Vojvodina and the Provincial Secretary of Agriculture, I have the honour to greet the participants at this important International Conference.

Let me now inform you, in a few words, about the policy agreed upon and about our plans for the development of agriculture and the food industry, that during the next five years and even over a longer period will be two very important segments of the general economic development of Yugoslavia. During the period from 1976 to 1980, we are planning to increase agricultural production at a rate of 4% per annum in Yugoslavia and at 5.2% in Vojvodina. The financial basis for the realis­ation of this plan represents investments in agriculture and the food industry at a level of 8% of the total Yugoslav

102 investments in the economy.

The region you are in at present is one of the leading agricultural districts of our country, for Vojvodina provides more than 50% of .Yugoslavian market surpluses in wheat, maize and pork. Market surpluses in some other products are slightly lower, but still very significant. By 1980 we have planned to double the production of feed mixtures and to increase the number of cattle to total 544 000, or 20% over 1975.

The value of our cattle production is 20% of the total agricultural production and 40% of the value of total livestock production.

In addition to larger investments, better utilisation of existing capacities will contribute to the increase in Vojvodina feed production, especially completion of the Danube-Tisa-Danube hydro-system, that is expected by 1980 to have facilities for the irrigation of 100 000 ha so allowing for two harvests a year. The gradual increase of the area of land under social­istic property will be another way of contributing to the intensive food production in Vojvodina.

The development of the agro-industrial complex, the develop­ment of cattle breeding and industry based on it, enjoys special attention and is considered a most important factor of intensifi­cation, industrialisation and restructuring of the whole agri­cultural production and the Province's economy in general.

It is expected that by 1980 Yugoslavia will produce 11 000 000 tons of maize of which Vojvodina's part, with 3 600 000 tons, is about 37%. To achieve this plan, science will contribute largely to the development of agriculture. For instance, by the practical application of scientific principles, yields of maize grain increased from 2.08 t/ha in 1956 to 5.76 t/ha in 1975. The average milk yield of cows has increased from 2 077 litres in 1957 to 3 700 litres in 1975.

Requirements for the realisation of the five-year plan are: secure raw materials, modern technology, cadres, marketing and financial means.

I hope that, from some of the details I have put forward, areas of common interest may be found between Yugoslavia and the countries of the European Economic Community. The Government of Yugoslavia is going to support any initiative of

103

scientists for international co-operation in developing agricultural production and preparing more suitable conditions for a better tomorrow.

I wish you a successful work and new contacts during and after the realisation of international projects, since we are considering this conference the beginning of successful creative endeavours of all interested partners.

Dr. A. Sreckovic

The welcome from the Commission of the European Communities will be extended by Mr. Raymond Craps, Director in the Directorate-General for Agriculture.

Mr. Raymond Craps

I would like to take this opportunity, on behalf of the Commission to thank you very warmly, Mr. Secretary, and through you the Government of your country and the Government of the people of Vojvodina, for the extremely kind invitation which has been extended to this group to come and work here on a very important subject. I wish, at the same time, to thank the people in Yugoslavia who have been working for months to organise this meeting - you Dr. Sreckovic, Dr. Cobic, and all your colleagues. I also want to thank all those who, as soon as we arrived in Yugoslavia, accepted us, showed us what your hospitality is, and made sure that we are going to start working in these few days in the best possible conditions. I should, at the same time, underline that at this meeting we are very numerous. We come not only from all the member states of the Community but include participants from nine European countries outside the Community and even an American guest, Dr.' Vetter, from the Iowa State University. It might be as well to explain that this is a meeting which has been asked for by COST (the Committee of Senior Officials in Science and Technology). It is something which has been set up by invitation from the Community to non-member countries in Europe. It has been very strongly felt within the Community from the beginning, and is now being more fully expressed, that there is a need

to have better co-ordination, better co-operation in scientific activities - co-operation which would benefit from that closer and organised link between the Community and non-member states. I think it is really important because this meeting is the very first - but certainly not the last - agricultural research activity which is being carried out in a framework which is partly outside the Community. Another feature of this meeting is that it is not an isolated activity because it is linked with existing research co-ordination programmes. In the Community the Commission has launched a series of programmes of co-ordination of agricultural research, some concentrating on protein production and improvement, others on beef production. Again we have made a link with something already in existence on which we are counting to improve co-ordination among research people and research organisations, and again, an expression of that feeling of the Community that we should push as much as possible towards the extension of co-operation within research. This means international co-operation, not restricted to its own territory, but open as much as possible to everybody who can bring something to it and profit from it. I would like very much to emphasise that aspect because I believe it is a special occasion. Of course as a layman you would not expect me to talk very much about research. Layman as I am, however, I would like to emphasise the very deep importance of the subject of this meeting, on maize production and on maize as a cattle feed. From the progress which is going to be made from this meeting, although it might take some time, I am quite sure that there is going to be a very significant contribution to the improvement of productivity on many farms and that is the purpose, I believe, of your own mission of research.

I am not going to expand further in the programme; I would like, in renewing my thanks to everybody who has worked in advance, to say that I know, at this moment, that it will be a success and also to say that we are very sorry that Mr. L'Hermite who is the man, on the side of the Commission, who has been in charge of this programme, was taken ill last week and has been unable to come - I am awfully sorry on his behalf as I am sure that he would have loved to have been here.

105 At the same time we are very lucky to have Dr. Tayler. He has done so much work; he is not going to let us get away with not working - this is a working conference. We are going to start very early in the morning. We are here to work, we are here to launch something in the form of co-ordination policy. I do, very sincerely, offer my best wishes for the success of your conference.

Dr. A. Sreckovid*

A welcome will now be extended by Professor Reljin of the Faculty of Agriculture.

Professor Reljin

Ladies and gentlemen, dear guests. Allow me to welcome, in the name of the Faculty of Agriculture, Novi Sad, this eminent meeting, and to wish you a successful working conference.

This Faculty is a relatively young school and scientific institution established only 22 years ago. However, during this period it has grown to an important educational and scientific centre. At the Faculty at the moment there are more than 1 500 students and at its 10 institutes and two experi­mental farms, there are 1 300 people working of which 400 are Faculty graduates. At this Faculty we have a parallel develop­ment of the research work in the field of maize production as well as in cattle breeding. Our area is a distinct maize region and meat production is largely based just on cattle nutrition with maize. Intensive beef production to a great extent utilises the maize plant as a food in various forms. Therefore, problems underlined in the programme of your scientific meeting are of outstanding practical importance for all the participants as well as on a much wider scale. However, do not forget that maize is also a very tasty and healthy food for people, especially when served together with a good piece of young beef.

Once more I wish you great success in your work and a pleasant stay in our town.

107

SESSION I

SURVEY OF THE USE OF MAIZE FOR LIVESTOCK FEEDING IN EACH COUNTRY

Area of maize grown and proportion of total area grown as forage and grain crops. Quantity used for ruminants and non-ruminants, for beef cattle and dairy cattle. Varieties grown and proportionate use of different harvesting and conservation methods. Quantities and origin of maize grain imported for livestock feeding.

Beef production: form of maize feeding and supplements used in defined systems of production in relation to the climatic and economic factors which have led to the adoption of these systems.

Chairman: J.M. Wilkinson

Animal Feed Science and Technology. 1 (1976) 109­114 109 lilsevier Scientific Publishing Company. Amsterdam ­ Printed in The Netherlands

SURVEY OF THE MAIZE SITUATION IN ITALY

A. ROMITA Istituto Sperimentale per la Zootecnia ­ Roma, Italy.

The total agricultural area in Italy is 17 461 892 ha. The irrigated area is about 3 500 000 ha and more than one third of this is utilised for maize production.

The area cultivated for the production of maize grain was 1 120 000 ha in 1963 and decreased during the following 10 years. Thereafter there has been little change (Table 1).

TABLE 1 CULTIVATED AREA AND PRODUCTION PER HECTARE OF MAIZE IN ITALY

Years

1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975

Area Γ000 ha)

Hybrid maize

455.5 472.6 489.7 488.5 550.0 559.8 651.6 734.3 717.2 704.7 746.8 762.1 778.6

Local 1 Total varieties

665.0 599.7 537.9 499.2 461.6 406.7 347.5 291.5 217.3 186.4 143.5 127.9 118.3

1 120.5 1 072.3 1 027.6 987.7

1 011.6 966.5 999.1

1 025.8 934.5 891.1 890.3 890.0 896.9

Production (t/ha)

Hybrid maize

4.96 5.57 4.85 5.21 5.24 5.65 5.81 5.69 5.73 6.27 6.44 6.33 6.57

Local varieties

2.15 2.21 1.75 1.93 2.06 2.03 2.12 1.97 1.92 1.99 1.96 1.73 1.79

The production per ha increased from 4.96 tonnes (t) in 1963 to 6.57 t in 1975 (Table 1), and the total production from 3.7 million t in 1963 to 5.3 million t in 1975 (Table 2). This is due mainly to the progressive substitution of old local var­ieties (­82.21%) with hybrid maize (70.93%); the other factor that contributed to the increase in production was improved growing techniques and particularly the better use of fertilisers

110

and pesticides, control of weeds and the widespread use of irrigation.

TABLE 2

NATIONAL PRODUCTION OF MAIZE (million tonnes)

Years

1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975

Hybrid maize I Local varietie

2.260 2.632 2.376 2.545 2.909 3.162 3.784 4.179 4.111 4.419 4.807 4.821 5.115

1.432 1.325 0.941 0.965 0.951 0.829 0.735 0.575 0.417 0.371 0.282 0.222 0.212

Total

3.692

3.957

3.317

3.509

3.860

3.991

4.519

4.754

4.528

4.789

5.089

5.043

5.326

In I t a l y , maize c u l t i v a t i o n i s i n f l u e n c e d by t h e d i f f e r e n t

c l i m a t i c e n v i r o n m e n t s of t h e c o u n t r y . These d i f f e r e n c e s p r o d u c e

v a r i a t i o n b o t h i n a r e a and i n t h e v a r i e t i e s grown as i s shown

i n T a b l e 3 .

TABLE 3

MAIZE GRAIN; GEOGRAPHICAL DISTRIBUTION IN ITALY IN 1975

North Middle South Islands Total

Hybrid maize (ha) (million t)

65.327 8.971 3.418 0.146 77.863

4.430 0.489 0.186 0.010 5.114

Local varieties (ha)

0.976 1.839 8.877 0.142 11.835

(million t)

0.034 0.034 0.142 0.002 0.212

Total (ha) (million t)

66.303 10.810 19.296 0.289 89.698

4.463 0.523 0.328 0.012 5.326

I

In 1975 , 73.9% of t h e maize a r e a was in N o r t h e r n I t a l y , 12.1%

Ill in Central Italy, 13.7% in Southern Italy and 0.32% in the Islands.

Of the total maize area the percentage sown with hybrids was: 98.5%, 83.0%, 27.8% and 50.6% respectively in the north, central, south and islands.

Average production per ha was therefore higher in Northern Italy (6.73 t/ha) than in the central area (4.84 t/ha), in the south (2.67 t/ha) and in the islands (4.15 t/ha).

In 1975 the Italian regions with the largest maize area were: Veneto with 271 866 ha and Lombardia with 160 227 ha. These two areas represented 48% of the whole Italian maize area.

Maize forage, of which about 80% is used at the waxy stage of maturity, is widespread in Northern Italy (79.6%) as is shown in Table 4.

TABLE 4 MAIZE FORAGE GEOGRAPHICAL DISTRIBUTION (ha)

Northern Central Southern Islands Total

1972

217 921 45 815 8 374 1 784

273 894

1973

231 112 47 715 11 286 1 923

292 036

1974

258 726 47 609 16 335 2 599

325 165

Lombardia and Veneto cultivate 52.5% of the forage maize of the whole country.

The maize sown in Italy is produced by 15 specialised firms to give a total of about 200 individual varieties; the percent­age of genetic types sown is as follows: about 45% are simple hybrids, 35% three-way hybrids and 25% four-way hybrids. The standard FAO classes utilised, in decreasing order of importance are: 700 (32%), 600 (28%), 400 (15%), 500 (12%), 200 (8%), 300 (5%).

In Northern Italy three-way hybrids and less precocious classes prevail, while in Southern Italy four-way hybrids with classes of higher precocity are more widespread. Some popular commercial varieties are: Asgrow 58, Dekalb XL 71, Funks Top, Titano, Ulisse, Dedalo.

112

In Italy some varieties of maize forage with a high level of sugar are still utilised. About 20 000 ha of these maize var­ieties are grown in the particular area where Parmesan cheese is made. Opaque maize is still at an experimental stage. Waxy maize is grown to a limited extent (200 - 3 000 ha) for technical uses; Energamid is the most widespread variety.

The importation of maize seed (Table 5) was at a high level in 1972 and subsequently decreased somewhat. The main countries of origin are Yugoslavia, USA, France and Romania. Our export­ation of maize seed is not very important (see Table 6).

TABLE 5 IMPORT OF HYBRID MAIZE SEED (tonnes)

Yugoslavia USA Romania France Austria Germany Others Total

1972

3 761 1 695 -399 153 4

375 6 389

1973

2 403 875 -679 16 4

786 4 764

1974

1 874 1 492 817 634 --904

5 720

1975

2 034 1 388 843 779 --42

5 086

TABLE 6 EXPORT OF HYBRID MAIZE FOR SEED (tonnes)

USA Spain France Hungary Albania Germany Yugoslavia Others Total

1972 272 389 43 ---186 876

1 767

1973 -104 293 --44 19

1 283 1 693

1974 --156 386 204 121 -121 988

1975 402 98 42 ----26 568

113

Maize utilised for animal feeding and other uses, as shown in Table 7, is imported by Italy in large amounts (about 50% of our needs). USA and Argentina are the main sources. Also for this type of maize our exports (Table 8) are insignificant.

The total quantity of maize available is utilised as follows: 90.5% for animal feeding, 6.5% by industry, 2.7% for human con­sumption and 0.4% for seed.

TABLE 7 IMPORT OF MAIZE (tonnes)

USA Argentine Yugoslavia France Bulgaria Romania Others Total

1972

2 230 001 2 058 139

5 803 110 447 5 331

97 427 428

4 837 247

1973

2 546 541 2 020 601

48 717 100 388 7 085 137

278 764 5 002 233

1974

1 722 837 2 265 454 121 7O0 ---

105 898 4 215 890

1975

2 673 531 1 234 601

----

561 915 4 470 047

TABLE 8 EXPORTS OF MAIZE (tonnes)

France Germany Others Total

1972

3 697 180

27 155 31 033

1973

2 228 23

1 313 3 635

1974

1 353 -

95 1 453

1975

1 449 -

187 1 637

1

Maize forage is mainly ensiled and used in fattening animals that are generally slaughtered at 450 - 500 kg live weight.

To obtain a good quality carcass, animals are fed on a high plane of nutrition. Maize silage, supplemented with urea, can represent 50 - 60% of the diet while the other 40 - 50% is provided by concentrates.

The percentage of maize forage in the diets is highest for the youngest animals. Table 9 shows some rations according to Parigi-Bini (personal communication).

114

TABLE 9 SOME EXAMPLES OF RATIONS WITH MAIZE SILAGE AND GRAIN AND COB MEAL FOR INTENSIVE FATTENING

Live weight (kg)

Rations Corn silage (kg) Grain and cob meal (kg) Cereals (kg) Protein, mineral and vitamin supplement (kg)

130

1 5-6 2.5 -

1

- 220

""2 5-6 -2

1

220 - 350

Y~--J 10-12 10-12 4

.3

1 1

350 -

r~ 7-8 7 -

0.8-1 0

450

~ 2

7-8 -5

.8-1

470

Reference: Parigi-Bini, R.

Animal Feed Science and Technology. 1(1976) 115-123 I I S Elsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands

REVIEW OF PRODUCTION AND UTILISATION OF MAIZE FOR ANIMAL NUTRITION IN YUGOSLAVIA

A. SRECKOVIC Livestock Research Institute - Novi Sad, Yugoslavia

ABSTRACT

With a total area of almost 2 400 000 ha and with a total production of nearly 9.5 million tonnes at an average yield of about 4 t/ha in 1975, Yugoslavia belongs to the 8 - 1 0 largest producers of maize in the world, and to the 2 - 4 largest pro­ducers in Europe. Until now, production of grain has been dom­inant in Yugoslavia, while the production of maize as a forage crop especially for silage has been less developed.

Over 75% of the area under maize is sown with home produced hybrids. Some of these hybrids achieve average yields of more than 6 - 8 t of grain per ha and on some farms even 8 - 1 0 t/ha. The work on production of new hybrids is still going on, espec­ially those with high protein, high lysine and high oil content, as well as those with a shorter growing season to be grown as a catch crop particularly when irrigated.

Forage maize is consumed by cattle, especially dairy cows that are fed mainly on silage, and to a lesser extent on green maize or dehydrated whole maize plant. Beef cattle have until now been fed mainly on concentrate mixtures among which 3 - 4 types are dominant.

Owing to the state of the beef market and especially because of artificial barriers to trade in some countries in Europe, Yugoslavia has been obliged to examine her policy in respect of production quantitatively as well as technologically and even systems of feeding beef cattle have had to be. reconsidered. Very intensive scientific work and careful application of the results are being carried out.

INTRODUCTION

Yugoslavia belongs to the 8 - 1 0 largest producers of maize in the world and to the 2 - 4 largest producers in Europe. With

116

an area of about 2 400 000 ha, Yugoslavia contains more than 2.0% of the total area in the world sown to this crop and 19% of the area in Europe. The situation is very much the same if total production and yield per hectare are considered. In 1975, total production of maize grain was nearly 9.4 million tonnes and yield per hectare almost 4 tonnes.

These data show the considerable importance of the maize crop in Yugoslavia and they illustrate the efforts to attain one of the top positions in the world's production of maize. To increase and to improve maize production, Yugoslavia has all the necessary conditions, and our aim in the next 10 years is to increase maize production to more than 12 million tonnes and, at the same time, to reduce the area under this crop to 2 000 000 ha as well as to improve significantly the chemical composition and nutritive value of the maize grain.

Beside maize grain, Yugoslavia produces some other forms of maize which are especially important for animal nutrition such as green maize fodder, dehydrated maize harvested at the dough stage, and ensiled young maize crops at the milk and dough stage of maturity. Some parts of Yugoslavia are very convenient for maize produced as a second crop, after early harvested fodder and industrial crops, or after winter cereals. For this type of maize production, which is mainly used for silage or dehyd­ration, irrigation is increasingly used because the second half of the summer in this country is very often without enough nat­ural rainfall.

However, it should be emphasised that Yugoslavia has achieved great progress in the production of maize grain, while the pro­duction of other forms of maize has been less developed. There­fore, it is necessary to make special efforts in future to in­crease and improve these two forms of maize production.

PRODUCTION AND USE OF MAIZE

Areas and yields In the course of the last 10 years in Yugoslavia there has

been a gradual reduction in the total area of maize but also a gradual increase in total maize production. (Table 1).

117

TABLE 1 AREAS AND YIELDS OF MAIZE

Year

1966 1970 1973 1974 1975

Averages : 1973 - 1975 (3) 1966 - 1975 (10)

Total area (ha)

2 500 000 2 352 000 2 378 OOO 2 256 OOO 2 363 OOO

2 332 000 2 402 000

Total yield

(million tonnes)

8.0 6.9 8.3 8.0 9.4

8.6 7.8

Yield per ha (t)

3.2 2.9 3.5 3.6 4.0

3.7 3.2

In Yugoslavia, especially in the maize belt, maize is pro­duced under two different types of land ownership. Society owned land is usually in blocks of 2 000 to 30 000 ha and pri­vate land in areas of 1 - 10 ha. The ratio of these two kinds of property for total arable land is about 15 : 85 and for area under maize about 10 : 90. The yield difference between these two types of farms is rather big. Areas and yields for society owned farms are shown in Table 2.

TABLE 2 AREAS AND YIELDS ON SOCIETY OWNED FARMS

Year

1966 1970 1973 1974 1975

Averages : 1973 - 1975 (3) 1966 - 1975 (10)

Total area (ha)

204 OOO 190 000 259 OOO 230 OOO 261 OOO

250 000 232 900

Total production

(million tonnes)

1.2 1.0 1.4 1.3 1.6

1.4 1.3

Yield per ha (t)

5.7 5.5 5.8 5.8 6.1

5.9 5.6

Comparing the yields obtained per hectare on the large society farms with the average yields for both kinds of farms it is not difficult to see that the difference in favour of society farms amounts to 2.0 - 2.5 t/ha; thus the yield per ha on society farms is almost twice as big as on private farms. The latter are the biggest reserves for the possible future in­crease of yield per hectare, as well as the total production of maize in Yugoslavia.

TABLE 3 AREAS AND YIELDS OF GREEN MAIZE FODDER

Year and ownership of farm

1964 - 1973 (10) Average 1974 - total Society farms Private farms

Regular Area (ha)

43 601 35 810 15 873 19 937

sowing time Yield (t/ha)

24.4 25.7 33.5 19.6

Stubbl Area (ha)

13 380 7 470 718

6 752

e crop Yield (t/ha)

12.2 13.5 24.2 12.4

As mentioned earlier, production of maize for roughages and other products is not as well developed as that for grain. The author of this review and many other scientific workers and producers know from their own experience that this kind of pro­duction is spreading, and under irrigation yields of 50 - 70 t/ha could be achieved from sowings at the conventional time and 30 - 50 t/ha from stubble catch crops. These results are encouraging, especially because scientific workers and producers are already applying the new maize varieties and new technologies to this kind of production, which is of great interest for live­stock production, especially for cattle husbandry.

UTILISATION OF MAIZE

We do not have exact data about methods, amounts, forms and purposes of utilisation of maize in Yugoslavia. It is certain, however, that all the maize produced for roughage is fed to cattle, especially to dairy cows and heifers. Daily amounts,

119 predominantly of silage and rarely of fresh green fodder, in intensive agricultural regions are about 25 kg. In beef production and especially in fattening of young bulls (baby beef), maize as a roughage has been used in Yugoslavia in limited amounts. As a rule, under conditions of intensive production of beef, a concentrate is used which sometimes contains very small quantities of meal from the dehydrated maize plant. The concentrate is very often made of ground maize ears which constitute about 70% of the mixture which also contains a protein-mineral supplement.

More is known about the utilisation of maize grain. Of the total maize produced 3% is used for industrial processing, 21% for animal feed-industrial mixtures, 6% for export and 70% for animal feed-semi industrial mixtures (direct use on farms). From the abovementioned quantities for animal feed about 40% is con­sumed by pigs, 20% by cattle and about 40% by other domestic animals.

Varieties and hybrids For production of commercial maize grain, hybrid maize is

grown in the largest part of Yugoslavia. It is estimated that hybrid maize is grown on all society farms and on 70% of private farms. This means that on some areas - although in most cases only in atypical regions and farms - the old low yielding var­ieties of maize are grown. This is one of the reasons why private farmers achieve lower yields than society farms.

However, numerous maize hybrids occupy the real maize grow­ing areas so that very soon the whole of the maize production will be based on hybrid seed. Many hybrids have already been been created and more are still being created in order to satisfy different and specific climatic and agro-ecological conditions of the individual regions of Yugoslavia.

Up to 1975, about 100 hybrids of all vegetation groups (100 -800) had been officially recognised in Yugoslavia. Most of these hybrids have a relatively longer growing season (groups 400 - 800) which causes difficulties in ripening and harvesting of maize grain in some regions of Yugoslavia as well as in growing this cereal as a catch crop. It is therefore necessary to create new hybrids with a shorter growing season (100 - 400) with which some important problems of growing, harvesting, dehydrating and

120

contamination of maize grain, as animal feed, will need to be solved.

From about 100 officially recognised hybrids in Yugoslavia, 40 are single cross, 5 are three-way cross and 53 are double-cross. In this paper only the most widely used maize hybrids are mentioned, which are not only grown in Yugoslavia but are also exported in large quantities as seed to other countries. These hybrids are NS SC-70, NS-696, NS SC-73 (high oil), NS SC-418F (lysine), ZP SC-1A, ZP SC-3, ZP SC-71c, OS SC-295, OS SC-661 and BC 66-25. Under normal conditions the yields of some of these hybrids are from 7 to 8 t/ha but under optimum conditions more than 10 t/ha may be achieved. Exceptionally, the yields achieved range from 13 to 15 t/ha. In 1974, 30 000 t maize seed was exported from Yugoslavia.

Besides the conventional hybrid maize, some research instit­utions in Yugoslavia are creating their own versions of hybrid maize with special characteristics. First of all, there are versions of "Opaque-2" with an increased lysine content. At the same time work is proceeding on some versions of hybrid maize with higher oil content and also hybrids which are to be used as forage, especially silage, as the second crop on irrigated land.

Maize and beef production In Yugoslavia, in a very specific and well organised sys­

tem of production, about 500 OOO high quality young bulls are fattened per year. Most cows in the north-western, northern and central parts of Yugoslavia are of dual purpose breed for meat and milk, of Simmental type. There are over 2 million cows in these regions of Yugoslavia, of which more than 95% are on private farms. Calves for fattening are therefore produced on private farms and mostly in regions where large quantities of forages (for feeding the cows) and rather small amounts of con­centrated feed are produced. Calves are reared where they were born, generally on milk or milk replacer up to 80 - 120 kg live weight or 10 - 12 weeks of age. After that, an organised pur­chase of calves occurs and the animals are transferred mostly to private farms, to form groups of 50 - 100 animals. The calves are kept here up to about 220 kg and then removed to big

121

industrial fattening units on the large society farms (500 - 2000 animals at one place) or to the smaller privately-owned units, (30 - 200 animals), also of an industrial type.

This organisation of the production of fattening bulls is designed to make the best use of the resources available at each stage. In phase 1 the calves are reared on milk on farms where there are large amounts of roughages for feeding to cows. The cow is then used for milk production and the calves are moved to bigger groups (phase II) in areas, where, besides roughages, there are enough concentrate feeds to grow the calves to about 220 kg. Finally, in phase III - which is up to 430 kg - the bulls are removed to industrial housing and fed generally on concentrated diets.

Until 2 - 3 years ago, when the member countries of the European Community laid an embargo on Yugoslav beef, this system ensured a high, intensive, high quality and profitable production of beef. Some years ago this kind of meat was exported to the UK as "baby beef", after that to Israel and especially to Italy and to some other countries in Europe. The meat was of top quality and the prices were very satisfactory. Technology and the system ensured both of these things. Now, the situation is more complicated and it is difficult, in such types of production, to restore the balance between new markets on the one hand and new possibilities of production on the other. Efforts are cur­rently being made to find a scientific solution to this problem by studying new technological methods in order to be able to continue the already traditional production of high quality beef. For that reason Yugoslavia is very interested to 'take part in this conference and, perhaps, that is why Yugoslavia is host country and why we have reason to expect some benefits in the future from mutual investigations in this field.

As already stated, the fattening of bulls in Yugoslavia is usually from concentrated rations. Three typical mixtures used for this purpose are shown in Table 4.

Differences between these mixtures are not big and so they are not very important for the organisation, technology, and economy of beef production. However, in the present situation, when there are many difficulties in marketing Yugoslav beef, it is possible that some modifications to these types of rations

122

may be needed. These will depend on research results proven in practice, and also on economic analyses.

TABLE 4 COMPOSITION AND NUTRITIVE VALUE OF CONCENTRATE MIXTURES FOR FATTENING BULLS

Feed

Composition %

Maize grain Maize ear Dehydrated maize plant Dried sugar beet pulp Sunflower oil meal Minerals + premix

Starch equivalent % Digestible crude protein '■

Daily amount of feed/kg Dally gain (kg)

Type I

Ground maize

85 ­

­

­

12 3

75.6 10.0 4 ­ 5 1.3

Type II

Ground maize ears

35 48 ­

­

14 3

66.6 10.0 5 ­ 6 1.2

Type III

Dehydrated maize plant

45 ­

30 6 16 3

63.3 10.0 6 ­ 7 1.1

Further information may be obtained from: Bacvanski, S. and Cobic, T., 1975. Razvoj i unapredjenje govedarstva í

proizvodnja govedjeg mesa i mleka u Jugoslaviji. Kongres o proizvodnji ljudske hrane u Jugoslaviji, Novi Sad.

Dumanović, J. and Delie", M., 1975. Geneticke mogućnosti poveãanja sadrzaja i pobol sanja kvaliteta proteina kukuruza. Kongres o proizvodnji ljudske hrane u Jugoslaviji, Novi Sad.

Djonović, M. and Lazin, M., 1975. Ekonomski znacaj kukuruza i pravci njegove potpunije valorizadje. Savetovanje o kukuruzu u Vojvodini, Duboka.

Milatovic, Lj., Gotlin, J. and Kauzlarić, Ljiljana, 1975. Proizvodnja, prerada i promet psenice i kukuruza, kao i njihovih preradjevina u SFRJ Kongres o proizvodnji ljudske hrane u Jugoslaviji, Novi Sad.

Petek, M. and Valosek, Visnja, 1972. Istrazivanja hranidbene vrijednosti kukuruza "Opaque­2" u ishrani svinja. Agronomoske informacije, br.1­2/72 SZS, 1975. Ratarstvo, vocarstvo i vinogradarstvo. Statisticki bilten, 923, 1975.

123 szSf 1975. Indeks. Mesecni pregled privredne statistike SFRJ, 3, 1975

Trifunovic, V., 1975. Problemi i razvojne'mogucnosti proizvodnje kukuruza u Jugoslavije. Kongres o proizvodnji ljudske hrane u Jugoslaviji, Novi Sad.

Animal Feed Science and Technology. 1(1976) 125-127 125 Elsevier Scientific Publishing Company. Amsterdam - Printed in The Netherlands

USE OF MAIZE FOR RUMINANTS AND PIG FEEDING IN GREECE

D. MERGOUNIS Station of Agricultural Research and Cattle Breeding, Athens, Greece.

INTRODUCTION

Maize growing in Greece is becoming more and more important, on the one hand because of the development of cattle breeding in Greece and on the other hand owing to the creation of various agricultural industries using maize as a raw material.

It is the only cereal in which Greece is not self-sufficient. As maize is a very important crop for cattle feeding and con­tributes, with other factors, to the increase in animal production, efforts are being made to ensure that Greece becomes as self-sufficient as possible in this crop

DISTRIBUTION OF THE VARIOUS VARIETIES OF MAIZE

The cultivated area for maize grain production covers 134 600 ha, of which:

112 000 ha are cultivated with American or Greek maize hybrids 22 600 are cultivated with common maize

Greek hybrids may be divided into three categories depending on their precocity and their requirements:

1st Category: Early hybrids, earlier or of the same precocity as Min. 607 ( I 70, CI 20, CI 400) . 2nd Category: Hybrids of an intermediate precocity, a little earlier than the American hybrid Wise 641 (CI 228) 3rd Category: Late hybrids such as OHC 92. The cultivated area of each hybrid is shown in Table 1.

Maize production in Greece amounts to 540 000 tonnes. Of this quantity only 35 000 tonnes comes from common maize and the remainder comes from hybrids.

126 TABLE 1 CULTIVATED AREA OF EACH HYBRID

No.

1 2 3 4 5 6

TOTAL

Hybrid

OHC 92 CI 20 CI 70 CI 228 CI 400 Other hybrids

Cultivated area

34 28 3 36 7 2

112

200 100 COO 300 600 800

000

(ha) ¡

TABLE 2 LIVESTOCK POPULATION SPECIES IN GREECE

Species

Cattle Sheep Goats Swine

Number

1 244 416 8 403 400 4 514 000 788 400

Exploitation form

-677 800 improved 897 000 improved 602 000 fattened

7 3

-725 600 common 617 OOO common 186 400 grown

TABLE 3 PERCENTAGE CONTRIBUTION OP MAIZE IN THE FEEDING RATION OF IMPROVED LIVESTOCK

Species

Cattle Sheep Goats Swine Fowls

Percentage of maize

30-60% in the feeding mixture Basic supplementary feed Basic supplementary feed 30-70% of the grain in the diet 60% of the ration

Given that the requirement for maize by improved and local beef cattle amounts to 1 240 000 t and that the relative pro­duction in Greece is 540 000 t, the remaining 700 000 t comes

127 from imports. Most of this deficit (90%) is covered by USA importations.

We are trying to meet this deficit, firstly, by increasing the cultivated areas with maize, and secondly, by increasing the productivity per ha by improving the cultural technique and by replacing common maize with hybrids.

As far as the first aim is concerned, that is the increase of the maize area, the possibilities are very limited owing to the lack of sufficient area for cultivation. It is not possible to replace other more profitable crops with maize.

As far as the second aim is concerned we think that this is the only way of securing satisfactory results for the solution of our problem.

As maize feeding plays a leading role in meat production for beef and for other livestock we aim for, firstly, the use of maize of a very high protein value for feeding lambs and young swine, and secondly, the creation of new, very productive hybrids. For the first category of research we have no results. However, studies are currently being undertaken on:

a) Lamb fattening with maize of very high protein value (14%) in comparison with cotton seed cake and soya bean meal b) Young swine fattening with maize of very high protein value, in comparison with common maize feeding c) Determination of the nutritive value of maize of very high protein value for feeding young swine. In the second category of research the results are

satisfactory and encouraging.

Animal Feed Science and Technology. 1 (1976) 129-136 Elsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands

SURVEY OF THE USE OF MAIZE FOR LIVESTOCK FEEDING IN SPAIN 129

G. GONZALEZ Instituto de Alimentación y Productividad Animal, CSIC, Ciudad Universitaria, Madrid-3, Spain. and A. MONTEAGUDO INIA, Avda. Puerta de Hierro s/n, Madrid-3, Spain.

AREA AND YIELDS

Maize in Spain has been traditionally cultivated for grain production. In this respect the maize acreage has remained nearly constant at about 500 000 ha since 1965. Nevertheless, during the last ten years there has been a growing interest in maize as a green forage crop, which accounts for the slight increase in the total area under maize during that time (Table 1). At present nearly 600 000 ha are under maize, of which 105 000 are sown for silage. The latter figure represents nearly 6% of the total acreage of forage crops in this country.

TABLE 1 AREAS AND YIELDS OF MAIZE IN SPAIN

Year

1965 1966 1971 1972 1973 1974 1975*

Area (1000 ha) Grain

478.3 482.2 543.5 533.7 522.7 500.5 500.0

Forage

38.1 39.7 69.0 79.7 91.1 98.0 105.0

Yield (t/ha) Grain

2.39 2.39 3.78 3.60 3.90 3.98 4.0O

Forage

33.6 31.2 34.0 35.8 34.2 32.9 34.0

Production Grain

1 141.9 1 154.3 2 056.3 1 922.6 2 037.9 1 992.7 2 OOO.O

(1O0O t) Forage

1 282.0 1 227.0 2 348.0 2 701.0 3 118.0 3 229.0

-* Estimated figures

The Spanish climate makes possible the cultivation of maize for grain in most parts of the country, provided there is enough water. Nevertheless this crop is nainly concentrated in the north (Galicia and Cantábrica) where summer rainfall makes

TABLE 2 DISTRIBUTION AND YIELDS OF IRRIGATED AND NON-IRRIGATED MAIZE AREA IN SPAIN (1974)

Zone

Cantábrica Ebro Cataluña Duero Centro Levante Extremadura Andalucía Canarias

Total

Irrigated Area (1000 ha) Grain

21.1 81.8 31.9 17.9 18.5 21.2 49.6 51.0 1.8

294.8

Forage

3.8 2.4 6.8 5.3 3.1 1.9 4.5 6.9 0.9

35.6

Yields Grain

t/ha

40.0 57.1 65.8 41.5 56.1 48.8 4O.0 50.7 15.5

50.9

Total (1000 t)

84.4 467.3 209.9 74.3 103.7 103.4 198.4 253.6 2.8

1497.8

Forage t/ha

36.3 35.2 40.7 50.3 33.1 28.9 43.4 30.0 12.7

310.6

Total (1000 t)

137.9 84.5 276.7 266.6 102.6 54.9 195.3 207.0 11.4

1336.9

Non-Irrigated Area (1000 ha! Grain

182.2 1.1 12.7 0.6 0.2 4.4 0.5 2.4 1.5

205.6

Forage

46.3 1.0 7.4 2.8 0.5 0.1 1.2 2.1 0.6

62.0

Yields Grain

t/ha

25.3 26.2 17.1 21.3 18.6 9.5 5.0 8.3 6.2

24.0

Total (10O0 t)

461.5 2.9 21.4 1.3 0.4 4.1 0.2 1-9 0.9

494.6

Forage t/ha

35.6 14.1 10.8 21.5 9.2 4.7 8.5 12.6 4.6

121.6

Total (1000 t)

164.8 14.1 79.9 60.2 4.6 0.5 10.2 26.5 2.8

363.6

131 irrigation unnecessary, and in the Ebro Valley, Andalucía and Extremadura under artificial irrigation (Table 2).

Yields of grain and forage vary considerably from one region to another and even in the same region according to local conditions, cultivare used, agronomic care, etc. The national mean yield of grain has increased very sharply during the last ten years, from 2.4 in 1965 to 4.0 t/ha in 1975. The yield of forage, on the other hand, remains quite constant at about 33 t/ha. However, in good conditions yields of 11 t/ha of grain and 80 t/ha of forage have been recorded.

USE OF MAIZE CROP AND VARIETIES GROWN

Maize grain is mainly used for the production of concen­trates in the feed industry: 55 - 65% for poultry, 20 - 25% for pigs and 15 - 20% for ruminants, of which some 20% is consumed by sheep. The ratio of maize used for beef to that used for dairy cattle is about 5 : 3 . Nevertheless, more than one million tonnes of maize are used by farmers in the cattle area (Cantábrica).

Local varieties sown in Spain represent 25% of the total area, the other 75% being occupied by hybrids, of which those of the FAO maturity 600 to 800 represent 65% of the total area. In 1974 12 400 tonnes of certified seed were used (Table 3).

TABLE 3 MAIZE HYBRIDS CULTIVATED IN SPAIN (1974)

FAO Index

200 300 400 500 600 700 800 900 1000 Total

Certified seed tonnes 80.5

1 242.1 224.4

1 387.0 1 842.5 2 685.9 2 957.1 1 278.5 698.8

12 396.8

% 0.6 10.0 1.8 11.2 14.9 21.7 23.9 10.3 5.6

1O0.0

132 The hybrids grown are: 80% double hybrids, 13% single cross

and 7% three-way cross. The amount of registered hybrid seed for forage only represents 10.6% of the total amount, because a large part of the area under forage maize was grown from seed of local varieties, or from the same local hybrids as those used for grain production (Table 4) .

TABLE 4 TYPE OF MAIZE HYBRID SEED (1974)

Utilisation

Grain Grain Grain Silage

Total

Type of cross

Double Three-way Single cross

-

Certified seed tonnes

9 952.9 880.0

1 563.9 1 463.2

13 860.0

%

71.8 6.3 11.3 10.6

100.0

QUANTITIES AND ORIGIN OF MAIZE GRAIN IMPORTED

The percentage of seed for grain of Spanish origin is only around 20%. The rest comes mainly from the USA but a lot of inbred lines and single crosses are cultivated in Spain with other genetic material being imported (Table 5).

Maize grain imported mainly for the feed industry has increased during the last ten years from 1.5 in 1964 to 4.5 million tonnes in 1974: 67.3% was imported from the USA and the rest from the Argentine and Brazil (Table 6). This amount represents more than twice the whole Spanish production (which was about 2.0 million tonnes in 1974) .

LIVESTOCK PRODUCTION SYSTEMS USING MAIZE AND SUPPLEMENTARY FEEDING

The feeding of maize silage, made with the whole plant when the ear is in the milk stage (or 'pastone'), to beef cattle, with appropriate supplements, is increasing on farms with artificial irrigation. The methods of feeding vary according

133

TABLE 5 ORIGIN OF MAIZE HYBRID SEED SOWN IN SPAIN (1974)

Origin

USA USA USA USA USA

Spain Spain Spain Spain

Total

Commercial name

Funks De Kalb Pioneer Asgrow Others

AD INIA Prodes DMB

Certified seed tonnes

3 194.6 2 593.6 1 494.6 1 087.9 1 611.8

1 864.1 239.2 169.9 141.1

12 396.8

%

25.7 ) 20.9 j 12.1 ) 80.7

· ■ ' !

13.3 )

15.0 ) 1 9 > 1 ­ 3 ) 19.3 1.3 ) 1.1 >

100.0

TABLE 6 AMOUNTS AND ORIGIN OF MAIZE GRAIN IMPORTED INTO SPAIN (1974)

Year

1965 1966 1971 1972 1973 1974* 1975**

Grain imported (1000 t)

1 559.9 2 428.5 2 056.7 2 382.7 2 717.6 4 061.0 4 500.0

* In 1974 the origins of maize grain imported (1000 t) were: Yugoslavia, 9.8 (0.2%); France, 10.8 (0.4%)¡ Brazil, 438.8 (10.9%); Argentine, 850.4 (21.2%); USA, 2700 (67.3%).

**Estimated.

134 to the region and season.

One system(A in Table 7) is intended to meet the target' of 12 months­old yearlings (380 ­ 400 kg LW) using Holstein, Friesian or Brown Swiss males. Maize silage is fed ad libitum from the fifth month of age with restricted amounts of lucerne, fresh or as hay, as well as decreasing quantities of a concen­trate ration of 12% digestible protein (DP) until the ninth month. From this time to slaughter the cattle are given lucerne, fresh or as hay, (4 kg DM/head/day maximum) and maize silage ad libitum (20 ­ 30 kg/head/day by the end of the period) In system Β (Table 7) the amount of a 14% DP concentrate ration is 4 kg/head/day and maize silage is given ad libitum.

Values for intake, nutritive value, and expected daily LWG for systems of feeding involving concentrates and maize silage, or maize silage and lucerne, are shown in Table 7.

Other methods of feeding are designed to produce cattle of 700 kg LW in 18 ­ 20 months with maize silage, lucerne and supplementary compound feeds as cereals (system C for summer and D for winter). The relevant data for these systems are shown in Table 8.

TABLE 7 FEEDING SYSTEMS FOR BEEF PRODUCTION (MONTHS 5 ­ 12)

Live weight (kg)

150 ISO

200 20O

275 275

350 350

425 425

System

A Β

A Β

A Β

A Β

A Β

Concen­

trates (kg/day)

2.0 4.0

0.5 4.0

­

4.0

­

4.0

­

4.0

Alfalfa hay (kg/day)

1.0 ­

2.5 ­

4.0 ­

4.0 ­

4.0 ­

Maize silage (kg/day)

10.0 3.0

15.0 6.0

15.0 13.5

26.0 17.5

30.0 21.0

Nutrients per head/day

DM (kg)

4.5 4.5

5.5 5.4

6.4 7.6

8.6 8.8

9.3 9.9

DP (g)

550 616

475 652

590 742

7O0 790

740 832

Feed units (Scandinavian)

4.0 3.5

4.0 4.2

4.2 5.3

5.8 6.3

6.4 7.3

Ca (g)

36 27

44 30

58 37

65 41

68 44

Ρ (g)

16 25

12 27

10 31

14 33

16 34

Expected

gain (g)

1 coo 1 050

950 1 050

900 1 300

1 loo 1 200

1 100 1 250

TABLE 8 FEEDING SYSTEMS FOR BEEF PRODUCTION (MONTHS 13 ­ 19)

Live weight (kg)

419 419

515 515

611 611

707 707

Age (months)

13 13

15 15

17 17

19 19

System

C D

C D

C D

C D

Concen­

trates (kg)

3.0 3.0

4.0 5.0

4.0 5.0

4.0 5.0

Alfalfa

Hay Fresh (kg) (kg)

15 1.0

15 l.O

15 1.0

15 1.0

Maize silage (kg)

25 30

25 30

33 35

40 40

DM (kg)

9.8 9.6

10.7 11.4

12.3 12.4

13.7 13.4

Nutrients per hea

DP (g)

890 770

970 910

1 050 960

1 120 1 010

Feed units (Scandinavian)

8.2 8.0

9.2 10.0

10.3 10.7

11.3 11.4

d/day

Ca (g)

80 56

78 72

83 75

86 78

Ρ tg)

33 35

37 44

40 46

43 48

Expected daily gain (g)

1 500 1 500

1 600 1 600

1 600 1 6θΟ

1 600 1 600

Animal Feed Science and Technology. 1 (1976) 137-139 137 Elsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands

SURVEY OF THE USE OF MAIZE FOR LIVESTOCK FEEDING IN PORTUGAL

J.S. da COSTA, Estaco Zootechnica National, Santarém, Portugal

Portugal has a total area of nine million ha but only 50% (4 130 million ha) can be used for agricultural production. Nevertheless, statistical analysis showed that only 1/3 of this area is economic to use.

The area of maize grown (360 000 ha) and the production (487 000 t) has decreased by 17% and 10% respectively in the last ten years (see Table 1).

In 1974 the yield of maize was 1 350 kg/ha which was 7% higher than the normal average.

TABLE 1 MAIZE AREA, YIELD AND PRODUCTION

Year

1963-1964 1972-1973 1973-1974

1975

Area

(ha)

432 303 372 343 359 794 382 000

(%) 100 86.1 83.2 88.4

Production of Grain

(1 OOO t)

543 509 486 519

(%) 100 93.8 89.5 95.6

Yield of Grain

(kg/ha)

1 257 1 366 1 350 1 359

(%) 100 108.7 107.4 108.1

The maize growing area in Portugal stands to the north of the River Tagus where the yield of the grain is highest, and where production represents about 90% of the total. The area of forages has increased in the last few years as a result of the more advanced feeding techniques used in dairy and beef cattle production.

The quantity of maize used in animal nutrition has increased in the last few years from 599 OOO t (1972) to 628 000 t (1973) , 769 000 t (1974) and 993 000 t (1975).

Maize is mainly used as grain in animal feeding. The pro­duction of feedingstuffs is shown in Table 2 according to its utilisation by different species.

TABLE 2 FEEDINGSTUFFS PRODUCTION (t)

Species

Poultry Pigs Cattle Sheep

TOTAL

Mean 1962-1967

131 828 130 999 106 813

--

Mean 1968-1970

306 217 336 643 298 175

--

1971

396 154 454 943 319 010 7 820

-

1972

471 742 519 333 364 408 5 784

1 380 619

1973

491 564 574 873 429 573 7 606

1 526 074

1974

586 114 672 843 473 866 10 607

1 769 196

1975

593 472 767 278 436 223 5 341

1 831 008

TABLE 3 FEEDINGSTUFFS FOR BEEF AND DAIRY CATTLE

Year

Beef cattle Dairy cattle

1973

212 377 214 325

1974

271 102 199 518

1975

249 575 179 914

TABLE 4 IMPORTS OF MAIZE GRAIN

Year Tonnes Million $

1971

516 880 34.2

1972

820 752 48.7

1973

821 319 68.6

1974

1 006 329 129.9

1975

1 188 183 157.5

139

The quantity of maize given to cattle in the last four years can be estimated from the tables to be, 67 711, 72 204, 90 689 and 130 025 for 1972-75 respectively.

Statistical figures of feedingstuffs for beef and dairy cattle produced in the years 1973 to 1975 are shown in Table 3.

Maize is used in the diet of cattle in different amounts, although the recommended levels in the diets are, for beef, 50 to 60%, and for dairy cattle, 30 to 40%.

The quantities of maize grain imported for livestock feed­ing have increased a great deal in the last few years and have doubled in the last four years as shown in Table 4.

The main importing countries have been USA and Angola. Maize grain is generally used in all parts of the country and it is utilised both in traditional and in most recently developed farming systems. In some places it is used alone as a finishing ration for beef production.

Animal Feed Science and Technology. 1 (1976) 141-147 Elsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands

MAIZE AND ANIMAL PRODUCTION IN FRANCE

141

C. LELONG

Institut Technique des Céréales et des Fourrages, Station Expérimentale de Boigneville, 91720 Maisse, France.

MAIZE PRODUCTION

The amount of land under maize production in France has increased considerably over the last 10 years, and seems to have reached a ceiling. From 1.3 million ha in 1968, it prog­ressed steadily, reaching 2.8 millions in 1975. (15 - 16% of the workable land - see Table 1.) This steady increase in the land used for maize growing is due largely to the introduction in the last 4 years of maize forage, the areas allotted to grain having stabilised.

TABLE 1 DEVELOPMENT OF THE AREA OF MAIZE GROWN AS FORAGE OR FOR GRAIN (million ha)

Year 1968 1970 1972 1973 1974 1975

Grain 1.02 1.48 1.90 1.95 1.91 1.96

Forage 0.31 0.40 0.58 0.62 O.80 0.87

Total 1.33 1.88 2.48 2.57 2.71 2.83

Maize grain is grown mainly in the south and on the plains of the northern central region. Maize forage is found more extensively in the animal farming regions of the west where it has undergone spectacular development. (The area under forage in Brittany and Normandy increased 8 - fold between 1968 and 1975). Figure 1 illustrates the importance of maize in the various regions and also the proportion grown as forage.

In the north of France, the lack of sun is responsible for the limited maize grain cultivation and here it is advisable to sow early varieties (FAO index lower than 200 for grain, or 250 for forage). The later varieties are most suited to

MAIZE GRAIN

MAIZE FORAGE

1975 Figure 1 Total area of maize forage and grain crops in 1968 and 1975

143

L...X Υ Χ >

FAO INDEX VARIETY ^ onn / Carghi Primeur 170 ^

z o° \ Blizzard G 188

* ~ „ ­ J

PROPORTIONATE USE

200 ■ 2 5 0 ­ LG LG

7 II

INRA 258 INRA 240 Adour 250 Dekalb 216 INRA 260

ΐ Star 304 INRA 400 INRA 508

530 > 6 0 0 _ Dekalb 12

250-300

300-350

350-600 ! IN \ IN ( U

Figure 2 Geographic distribution of maize varieties grown in France (FAO Index)

144 the Midi (FAO index higher, than 250). In Figure 2 it can be seen that two of these varieties cover 50% of the area planted with maize.

HARVESTING AND CONSERVATION METHODS

No exact statistics are available on the distribution of land in terms of harvesting. All maize forage is ensiled (mostly in clamp and bunker silos), apart from 10 000 ha which are dehydrated and perhaps as many used as green feed. Maize grain is preserved almost exclusively by drying, the use of moist ensiling or propionic acid treatment being rare. About a quarter of the drying is done in cribs and the remainder is artificially dried.

MAIZE UTILISATION

a) Maize forage This is given almost solely to cattle, feeding to sheep

still being in the experimental stage. Although it is not known with any certainty what proportion is used for beef or milk production, we venture an estimate of less than one third, perhaps a quarter, destined for beef cattle feeding.

b) Maize grain Very little is imported (about 4% of what is available)

and about half of the grain produced goes towards animal feeding. The other half is either exported (about 40%) or used indust­rially (7%) (See Figure 3).

More than 60% of the maize grain consumed by animals is in the form of mixed feeds produced by the feed industry, and about 40% is consumed on the farms where it is grown. We have no information on which animals consume this latter percentage - pigs and cattle would seem likely. On the other hand, the maize purchased by the compound feed industry is intended mainly for poultry (57% in 1972 - 73) and pigs (42% in 1972 -1973). Maize is primarily a poultry cereal and the amounts used for poultry feed are increasing. Nevertheless, maize provides only a small proportion of the total feed consumed by livestock in spite of its attractive price in comparison

PRODUCTION

IMPORTED

SUNDRIES

INDUSTR

ARMS

EXPORTED

COMPOUNDED FEEDS

ANIMAL FEEDING UTILISATION

Figure 3 Production and utilisation of maize yrain in France. (Average of crops grown in 1972/73 and 1973/74) £

146 with other cereals.

Table 2 emphasises the increasing importance of maize among the cereals used for animal consumption. In 197 3 - 74 maize had caught up with barley and overtaken wheat as a result of the purchasing policies of the compound feed manufacturers. Wheat, and especially barley, however remain the cereals which are the most consumed on the farms where they are produced.

TABLE 2 COMPARISON BETWEEN MAIZE, WHEAT AND BARLEY GRAIN AS ANIMAL FEEDS

Year

1965 - 66 1969 - 70 1973 - 74

Maize

1000 t

2.31 2.99 5.29

% 17 19 31

Wheat

1000 t

4.09 4.60 3.79

% 30 29 22

Barley

1000 t

4.66 5.56 5.27

% 34 36 31

Total cereals

1000 t

13.83 15.60 17.22

% 100 100 100

(Reference AGPB and Eurostat)

FORM OF MAIZE FEEDING

Maize silage rarely constitutes the complete winter diet for dairy cattle. It is fed together with hay, cabbages, or other ensiled or dehydrated fodder for part or all of the winter. With high-producing cows, supplementary energy is provided by one of the cereals, maize, wheat, barley,or a mixture of wheat and barley. Urea and minerals are sometimes added to maize silage before ensiling.

For beef cattle production, maize silage constitutes the major part of the feed ration and is often supplemented with 1 or 2 kg of dry cereal per day (except in early maturing breeds such as Friesians). One kg of soya or groundnut meal provides the necessary nitrogen, and sometimes small quantities of hay are added. Some farmers use diets of higher energy concentration. These may include maize silage with large quantities of dry or moist cereals, or dried ears, ear silage moist or dry grain and hay or straw. This practice, however, is not widespread.

147 Fattening feeds are given to bulls from the time they are

weaned (at 3 months of age in dairy breeds, or 8 or 9 months of age in beef breeds) to ensure rapid rates of growth. They may also be given to castrated animals after one or two seasons at pasture.

This is a brief glimpse of the production and use of maize in France. Much complementary information is needed to provide explanations and details of what has been said. This suffices to give an overall impression of the maize situation in France in relation to that in other European countries.

Animal Feed Science and Technology. 1(1976) 149­151 149 Elsevier Scientific Publishing Company, Amsterdam ­ Printed in The Netherlands

SURVEY OF THE USE OF MAIZE FOR LIVESTOCK FEEDING IN SWITZERLAND

H. SCHNEEBERGER Swiss Federal Research Station for Animal Production, Grangeneuve 1725 Posieux FR, Switzerland.

AREA

In Switzerland the maize area has increased 10­fold over the last 20 years (whole­crop, 7­fold; grain maize, including maize­cob­mix, 20­fold). During the same period of time the yield of maize grain increased from 3 500 to 6 500 kg/ha (85% dry matter). The large expansion of the maize area is partly due to the provision of a cultivation subsidy.

The proportion of maize in the total arable land increased from 1.6% in 1955 to about 17% in 1975. The expansion occurred mostly at the cost of the cultivation of potatoes.

TABLE 1 DEVELOPMENT OF THE MAIZE AREA IN SWITZERLAND

Year

1955 1965 1970 1975*

Maize (ha)

Whole crop

3 000 5 200 11 200 22 400

Grain (incl. maize­

cob­mix)

1 100 4 300 9 3O0 21 300

Proportion of arable

Maize

1.6 3.9 8.3 17.0

Potatoes

19.6 15.0 12.2 9.0

land (%)

Cereals

65.2 68.2 65.9 62.0

♦Provisional figures Source: Statistical inquiries and estimations 1975, published by the Swiss Farmers Union, Brugg.

150

APPORTIONMENT OF MAIZE PRODUCTION, INCLUDING MAIZE IMPORTS TO DIFFERENT ANIMAL CATEGORIES

No official information exists on the quantities of maize which are fed to different animal categories in our country. The following figures present estimated values for the year 1975. Accordingly, the production of whole crop maize amounted to 336 OOO tons dry matter (22 400 ha χ 15 t dry matter per ha). This feed was only used for ruminants, and of that approximately one third for dairy cattle and two thirds for beef cattle.

By estimation in 1975, there were about 385 000 t of maize grain (maize-cob-mix included) available. Approximately two thirds of this quantity was imported and one third produced in the country. Of the imported maize, about 95% was probably used for feeding non-ruminants (pigs, poultry), whereas 80% of home-produced maize grain and maize-cob-mix was given to cattle (65% to beef cattle, 15% to dairy cattle).

VARIETIES

In Switzerland the cultivation of mid-early varieties is dominant. After extensive evaluation (cultivation during three years in ten different places), the most suitable varieties are accepted in the standard list of the Swiss Federation for Seed Producers.

In practice the following varieties are most common: Grain-maize (including maize-cob-mix) = ORLA 264 and 312

INRA 258 LG 11

Maize for silage (whole crop) = ORLA 2 70 and 2 30 LG 11

The seed used in 1975 is estimated at 1 500 t. One half of this quantity is provided by home production, the other by imports (mainly from France).

HARVESTING AND CONSERVATION METHODS

No statistical information exists in our country on this subject so that we have to be content with estimates.

151 Only about 2% of the whole-crop maize produced is used as

green fodder, about 3% is artificially dried and the remaining 95% is used for silage.

Of the cultivated varieties of grain-maize, about 70% is harvested as "ripe" maize and about 30% as maize-cob-mix and high-moisture grain for silage.

USE OF MAIZE FOR BEEF CATTLE

As a basic feed for beef cattle, maize can be used in different forms :

whole plant - fresh - for silage - artificially dried

maize-cob-mix or ground high-moisture-maize grain - for silage

The feeding of green whole-crop maize to fattening animals is limited to 4 - 6 weeks in autumn. As mentioned, only about 2% of the whole-crop maize is fed as green fodder.

Maize silage (whole plant) is the most important basic feed for beef cattle. The harvest occurs at the dough to mealy endosperm stage, the crop being chopped (approximately 5mm) and conserved mostly in tower silos (capacity 30 to 200m3). A supplement of concentrated feed, rich in protein is necessary. The daily ration of this supplement varies between 1 and 4 kg per animal, according to the quality of the silage, the fattening intensity and the sex of the animal.

On some farms, maize silage is fed together with grass silage rich in protein.

The artificially dried whole maize plant is used as a supple­mentary feed for dairy cattle or fattening animals at pasture in quantities of 1 to 2 kg per animal per day. As a basic feed in fattening, artificially dried maize is too expensive.

Maize-cob-mix and ground high-moisture-maize grain are partly used on larger fattening farms for young bulls in the west part of Switzerland, where climatic conditions are favour­able for the ripening of maize. This feed is then supplemented by protein concentrate, and hay or straw. This feeding system requires more arable land for the same number of animals, but needs less silo room than for the feeding of whole-crop silage.

Animai Feed Science and Technology. 1 (1976) 153-155 153 Elsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands

SURVEY OF THE USE OF MAIZE FOR LIVESTOCK FEEDING IN AUSTRIA

B. LABER No. Landes-Landwirtschaftskammer 1014 Wein I., Lowelstrasse 16, Austria.

As in other European countries, the area of maize in Austria has increased rapidly during the last ten years.

Development of the area of maize in recent years. a) Maize grain 1965 49 981 ha

1975 143 743 ha b) Maize for forage 1972 52 387 ha

1975 80 255 ha Relation between roughage area and feed grains area in 1974 Roughage area 1 333 968 ha Feed grains area excluding maize 444 249 ha Total area of maize 221 776 ha There is no exact survey of the use of maize for ruminants

and non-ruminants. The use can only be estimated. Eighty per cent of the maize grain is used for pigs and

poultry and only 20% for cattle, of which half is used for dairy cattle and half for beef cattle. The total production of maize grain in the year 1975 was 980 523 t, with an average yield of 6.8 t/ha. (15% moisture content).

Maize forage is given only to cattle. In 1975 the total production of maize forage was 4.3 million tons, with an average yield of 54.3 t/ha.

The most common varieties of maize are: Early varieties INRA 2 58

LG 11 AUSTRIA 290

Other varieties AUSTRIA 390 STAR 304 AUSTRIA 430 FUNKS G 350

Seeding rate Rainy area 90 000 - 100 000 plants/ha Dry area 55 000 - 85 000 plants/ha

154

Plants/ha Rainy area 70 000 - 80 000 plants Dry area 50 000 - 70 000 plants Fertiliser recommendation Maize grain normal yield high yield Ν 120 kg/ha 160 kg/ha* P2°5 110 kg/ha 160 kg/ha K20 200 kg/ha 280 kg/ha Maize forage normal yield high yield Ν 150 kg/ha* 200 kg/ha* P 20 5 100 kg/ha 150 kg/ha K20 200 kg/ha 280 kg/ha *two applications

CONSERVATION METHODS

Maize grain About 80% of the yield is preserved by drying and about

20% is ensiled. The quantity ensiled is tending to increase. Maize forage Nearly all maize forage is ensiled, mostly in trench silos,

but also in tower silos.

NUTRIENT CONTENT

On the basis of a large number of analyses, the nutrient content of maize grain can be estimated to be about 820 g/kg.

The dry matter content of maize silage (forage) averages about 28% with a starch equivalent content of about 170 and a content of protein of about 13% of the DM.

Change in prices for maize and barley. Maize grain Barley

1972 236.45 Schilling/lOOkg 236.85 Schilling/lOOkg 1975 285.83 Schilling/lOOkg 281.58 Schilling/lOOkg Quantities and origin of maize grain imported for livestock feeding 1974/75 20 800 t (from Hungary and USA) 1973/74 15 900 t 1972/73 39 000 t

155

BEEF PRODUCTION

Austria produces more beef than can be used in home consump­tion and therefore about 60 000 beef cattle have to be exported. The best beef breed in Austria is the Simmental and about 90% of beef is produced with this breed.

The following two systems of beef production are used: a) Fattening young cattle with a live weight about

300 - 400 kg up to a live weight about 600 - 650 kg. b) Fattening bull calves from about 100 kg live weight

up to a live weight of about 600 - 650 kg. For system a) sugar beet-top silage is sometimes used with potato pulp. For system b) maize silage (forage) is the basic ration.

Grass silage is not used much for beef cattle because it is rather expensive compared to maize silage but also the concentration of nutrients is not so high.

Fattening of bulls with concentrates is of no importance, because of the relatively high prices of concentrates.

FEEDING SYSTEMS WITH MAIZE SILAGE

Maize silage is fed twice daily ad libitum. The daily feed consumption averages about 15 - 16 kg per head. Soya bean meal is the most common protein supplement. In the final fattening period feed grains are also given at 1 - 2 kg per head per day. The daily ration of soya bean meal during the total feeding period averages 1 kg per head. Minerals are given at an average level of 0.08 kg per head. The use of urea is of no importance and its cost is calculated in relation to that of soya bean meal.

Total feed consumption of a young bull from 100 kg - 600 kg live weight averages :

7 500 kg maize silage 500 kg soya bean meal 450 kg feed grains 40 kg minerals

Depending on the quality of maize silage, 7 - 9 young bulls can be fed per ha.

Animal Feed Science and Technology. 1(1976) 157-165 157 Mscvier Scientific Publishing Company, Amsterdam — Printed in The Netherlands

USE OF MAIZE FOR LIVESTOCK FEEDING IN THE FEDERAL REPUBLIC OF GERMANY E. ZIMMER Institut für Grünlandwirtschaft, Futterbau und Futter­konservierung der Forschungsanstalt für Landwirtschaft D-3300 Braunschweig, Bundesallee 50, West Germany and J. ZSCHEISCHLER Bayerische Landesanstalt für Bodenkultur und Pflanzenbau D-8050 Freising-Weihenstephan, Vöttingerstr. 38, West Germany.

ABSTRACT

The area of maize is increasing continually in the Federal Republic of Germany because of better adaptation to the temper­ate, humid climate of the country.

Maize for grain is now planted on 108 000 ha, yielding 5.1 t/ha with variation from year to year of 5.8%, which is comparable to other grain species. Its position now is 2.1% of the total grain area.

Maize for silage in 1975 occupied 430 000 ha, yielding approximately 12.1 t/ha DM. This crop occupies 7.6% of total forage or 33.6% of fodder crops, excluding grassland. Climatic conditions allow the sowing of early to medium-early varieties for grain, and medium-early to medium-late varieties for silage. The nutritive value of the whole plant is not affected very much by the region.

Drygrain and high moisture corn are both harvested by combine. Corn-cob mix and picked, chopped ears are also used as feeds for beef cattle. Conservation is done by drying, ensiling, or ensiling after treatment with acid. Whole-crop silage is harvested within a range of 18 - 30% DM, using precision chopping, preferably at the dough stage of maturity. Conservation methods vary according to type of silo, farm size, availability of capital, manpower and method of utilisation. Production is 0.5 - 0.6 million tonnes of grain; importation is 3.2 million tonnes. Two thirds of home production is used for fattening pigs. Almost all of the whole-crop maize ia utilised by ruminants, but no estimated figure for particular use in milk or beef production can be given.

158 Fattening young bulls within 18 - 20 months up to 550 -

600 kg live weight on the basis of maize silage to appetite, supplemented by 1 - 3 kg concentrate, is common practice.

Feedlot systems on large farms are an exception. Fattening of small or medium-sized groups of animals is in barns, but also in loose housing systems. Hand feeding, mixing trailers and food troughs of all kinds are used.

Maize is considered as a crop with increasing significance, characterised by a high degree of interest by farmers and advisory services, as well as by research organisations in the country.

AREA OF MAIZE GROWN (Figure 1)

A combination of early maturity and high yield has pushed the acreage of maize in FRG further north, beyond the classical ecological sites in southern and south-western Germany. Increasing DM yields and average level of maturity are charact­eristics of adaptation to north-western conditions.

a ¿00 ·

» 1.1

IJ , / l i

0^—0 io rfTAfls TSE 7

1 7

l-"°' ΪΠ

'-Ί

FOR sine­e 1 1 1 1

­ ^ o­ ­

s

5

t ­

, ü * i u | _ f i l l , , FOR GRAIN

­I—«—r­i­l­I­l­

156« 59 70 71 7> 7Ì 7< 75

Fig .

Si SS 70 71 72 7J 7< 73

1 Area and yield of maize in the Federal Republic of Germany

159 Maize for grain has been sown on about 108 000 ha for the

past five years. Approximately 70% of this is located in the southern states of Bavaria, Baden-Württemberg and Rheinland-Pfalz. At present development has come to a standstill. Competition with small grains on the basis of attainable yields as well as a limited number of early maturing varieties might be limiting factors. Yields averaged 5.13 + 0.296 t/ha over a six year period (Table 1). The coefficient of variation of 5.8% does not indicate a greater fluctuation in yield than with other grain crops. For a long time the trend for yields to increase was estimated to be 0.098 t/ha of grain per year.

TABLE l GRAIN YIELD IN FRG (1970 - 1975)

Maize Winter barley Spring barley Oats Winter wheat Spring wheat Rye

Yield (t/ha)

5.13 4.43 3.51 3.63 4.41 4.07 3.45

SD (%)

5.8 8.6 8.8 9.7 8.6 8.2 5.2

Maize for silage or green feeding is increasing in area continuously. Approximately two-thirds is located in the south and the rate of growth there is higher than elsewhere. However one can imagine from testing programmes that better adapted varieties will change the situation for northern regions.

Yields are 43.3 t/ha fresh material. The coefficient of 5% for yield variation is low. Including DM values from seed test­ing stations dry matter yield can be calculated to be 12.1 t/ha (Table 2). Rate of growth was estimated to be 0.34 t/ha per year.

Compared with other fodder crops maize is highly superior.

160

TABLE 2

YIELDS OF FORAGE CROPS (1970 - 1975)

Maize Clover, clover/grass Alfalfa Ley Grass]and

Yield (t/ha)

12.14 6.63 6.87 5.97 5.89

SD (%)

7.3* 2.3 1.8 2.8 2.5

*Years 1969 - 1975, DM con ten t 1975 es t ima ted

Source: BML 1975; Haas 1976; Z s c h e i s c h l e r 1976

RELATION TO OTHER CROPS ( F i g u r e 2)

Maize f o r g r a i n now o c c u p i e s 2.1% of g r a i n a r e a or 3.8% of f o d d e r - g r a i n a r e a . Maize f o r s i l a g e now o c c u p i e s 7.6% of t o t a l f o r a g e - c r o p s and g r a s s l a n d , or 33.6% of f o r a g e - c r o p l a n d .

βΚΛΙΝ 5 298 0 00 Hi FORAGE CROPS < 997 000 HA

Fig. 2 Area of maize in relation to grain or forage crops, Federal Republic of Germany, 1974.

161

VARIETIES GROWN

The temperate and humid climate allows planting of early (FAO = 200) to medium-early (FAO 200 - 240) maturing varieties for grain, and medium-early (FAO 200 - 240) to medium-late (FAO 250 - 290) maturing varieties for silage or green-feeding.

The demand for maize for a certain climate is reflected in typical yields and yield variation for particular regions. On the other hand, nutritive value is not affected very much by maturity type (Table 3) (Zimmer, 1973) .

TABLE 3 YIELD AND NUTRITIVE VALUE OF DIFFERENT MATURITY TYPES OF WHOLE-CROP MAIZE

DM yield t/ha DM% SE/DM SE yield t/ha

DM yield t/ha DM% SE/DM SE yield t/ha

Maturity type: mid early 10.7 - 14.5 23.8 - 29.1 64.2 - 66.7 6.9 - 9.5

Maturity type: mid late 10.8 - 15.2 22.3 - 26.7 62.8 - 65.4 6.9 - 9.8

S% 15.0 10.0 1.9

15.7

S% 16.8 9.0 2.0 17.6

Even when comparing r e s u l t s between d i f f e r e n t c o u n t r i e s , one w i l l n o t i c e the same tendency (Table 4) (Zimmer, 1973).

TABLE 4 YIELD AND NUTRITIVE VALUE OF WHOLE-CROP MAIZE IN DIFFERENT REGIONS OF EUROPE

Region

Southern England Netherlands Germany

Northern Italy

Author

Thomson (1968) Dijkstra (1971) Liesegang (1965)

Giardini (1964)

Coefficient of variation, S%

Type

mid-early mid-late mid-early mid-late mid-late

DM%

23.1 18.4 26.4 24.5 33.0

19.9

DM t/ha

13.23 12.5 12.58 13.0 11.87

5.9

SE/100DM

63.3 60.6 65.5 64.1 66.2

3.2

SE t/ha 8.4 7.6 8.2 8.3 7.8

5.0

162

HARVESTING AND CONSERVATION ( T a b l e 5)

TABLE 5

HARVESTING AND CONSERVATION OF MAIZE

High

moisture

grain

Maize whole crop

Stems and leaves

Maturity moisture cont. <25 25-35 35-50

>50

<70 ~75 <80

<50

Harvesting by

Combine Combine Combine

Picker-chopper

Chopper 1 - 3

rows

Chopper

Product

Grain HM-grain Corn­cob-mix Corn­cob-mix

Maize silage 6-12mm

Stalklage 6-12mm

Crude fibre

2-3 2-3 4-8

10-15

<20 20-22 22-24

>33

Conservation Ensiling

Drying Air- Con Org. tight vent.Acids

X X X ? X X X

X X ?

? X

(X) X (X) (X) (X) X (X) X

X

? Not recommended for technical or economic reasons (X) Possible, regarding certain technical or economic conditions.

Harvesting and conservation of maize grain demanded nev/ technology, because the moisture content is normally high in certain regions and years, exceeding the capability of combine harvesters. The harvesting method, therefore, depends first of all on moisture content. In the case of pig production one also has to consider the crude-fibre content as a limiting factor in feeding the material. Conservation method, on the other hand, will be affected by:

a) moisture content: whether drying or high-moisture conservation is suitable

b) availability of capital :

c) feeding system:

whether airtight, conventional storage is preferred or organic acid treatment suits the particular farm conditions whether year round or limited winter feeding is necessary.

163 From the above it is clear that generalised recommendations are not very useful.

Maize for silage is harvested within a range of 18 - 30% (or more) DM content, depending on variety and weather. The dough stage is considered to be the best. Precision chopping with a theoretical length of 4 - 8mm and affecting almost all kernels to prevent loss is recommended.

In relation to the area of maize, tractor mounted one-row choppers are used, or 2 to 4-row field choppers demanding a high tractor power. Type of silos, such as temporary clamp, plastic covered trench or bunker, tower, and the particular unloading technique are influenced by farm size, manpower, capital and feeding system.

Nutritive losses in different silo-types and the risk of heating during unloading is considered to be an important factor by farmers from the feeding and economic standpoint (Zimmer, 1973). General trends are towards bunker silos on bigger farms and mechanised tower silos on the fau-.ily farms which have a shortage of manpower and a demand for high and uniform quality in the silage.

Additions of 0.5% urea or Maisfertil (BASF - urea/mineral mix) are widely used. Prosil (based on ammonia) is under experimentation (Honig, 1975). Addition of organic acids, or other additives to stabilise fermentation and minimise nutrient losses, is still limited to special cases because maize is considered a crop which is easy to ensile. These questions are under discussion and experimentation.

In a few cases whole-plant maize is artificially dried for special purposes and examination.

Experimental work is being carried out on the ensiling of stalks and leaves for co-called stalklage. The same technology is used as with whole-crop maize silage, but open questions are the nutritive value, feeding regime, course of fermentation and stability of the product.

UTILISATION OF THE MAIZE HARVEST The production of 0.5 - 0.6 million tonnes of grain is in

contrast to an import of 3.2 million tonnes per year (1971/74). The major places of origin of the imported grain are France and the USA.

164 Consumption of home grown maize is fairly constant at 0.35

million tonnes. Sale to industry or between farms therefore only reaches 25 - 40% of the total amount produced. Compared to the volume of imported grain this is negligible (Haas, 1976). Utilisation takes place as dry corn or high moisture corn, mostly for fattening pigs. The proportion of grain given to ruminants is low. On the other hand, ruminants utilise almost all the maize silage and green maize. The amounts used in milk or beef production cannot be estimated.

FEEDING FOR BEEF PRODUCTION

Fattening young bulls within 18 - 20 months up to 550 - 600 kg live weight, using maize silage ad libitum as the only rough­age, or in combination with other silages, is common practice. Supplementation with energy is necessary in the form of 1 - 3 kg of concentrate. Corn-cob mix is used instead of other con­centrates where large areas of maize are available for harvesting by different methods.

The requirement of the beef animal for additional digestible crude protein is normally met by soya bean meal, horse bean, brewer's grains etc. Use of urea is calculated in competition with soya bean meal. Farmers furthermore pay a great deal of attention to mineral and vitamin supplementation. Maize silage, harvested at the dough stage and with the ear accounting for 45% of total dry yield, has to be complemented daily by approximately 40 g calcium, 16 g phosphorus, 6 g sodium and 4 000 IU vitamin A (Burgstaller, 1975).

Regarding the farm structure in Germany, the fattening of small or medium numbers of animals in barns, or of medium-sized groups in loose housing systems, is common. Feedlot systems on large farms are an exception. Therefore one will find most feeding systems based on hand feeding, using special transport­ation and / or mixing trailers and food troughs.

OUTLOOK

The breeding of new varieties with better adaptation and/or higher yields, or with .modified quality (lysine, net energy.

165 digestible fibre) demonstrates progress in seed testing programmes around the country. Research activities, particularly in the north-west, show possibilities of maize production which will soon be taken up by farmers because of certain advantages of this crop.

Interest by farmers is high, as well as a readiness for on-farm experimentation in plant production, protection, harvesting and conservation techniques, utilisation and feeding.

This complements many research activities in State and Federal institutions, from which one may consider maize in Germany as a crop which still has a big future.

REFERENCES

Anonymous 1976. Zur Sortenwahl bei Mais Ztschr. Mais, 1976, No. 1, 16-18. BML 1975. Statistisches Jahrbuch über Ernährung, Landwirtschaft und

Forsten, Paul Parey Verlag. Bundessortenamt, 1974. Beschreibende Sortenliste A. Strothe Verlag

Hannover. Burgstaller, G., 1974. Silomais - Bullenmast Ztschr. Mais, 1974, No.4, 3-4. Haas, G„, 1976. Deutsches Maiskomitee, persönliche information. Honig, H. and Zimmer, E., 1975. Experiments on the use of Prosil as an NPN-

additive for maize silages, (als Manuskript veröffentlicht) Report given at the Second Annual Silage Conference, July, 1975, Ann Arbor, USA.

Zimmer, E., 1973. Nährwert von Mais im frischen, silierten ung getrockneten Zustand (als Manuskript veröffentlicht) Report given at the European Association for Animal Production, Vienna, Sept. 1973.

Zscheischler, J., 1976. Früher reifende Sorten machen den Maisanbau sicherer. Bayr'. ldw. Wochenblatt, No. 6, 7. Febr. 1976.

Animal Feed Science and Technology, 1 (1976) 167­175 167 Hisevier Scientific Publishing Company, Amsterdam ­ Printed in The Netherlands

SURVEY OF THE USE OF MAIZE FOR LIVESTOCK FEEDING IN BELGIUM

B.G. COTTYN. CH.V. BOUCQUE and F.X. BUYSSE National Institute for Animal Nutrition, Scheideweg 12, B­9231 Gontrode, Belgium.

AREA OF MAIZE GROWN IN BELGIUM

The use of maize as a basic feedstuff in ruminant feeding has increased very rapidly in Belgium in recent years. Accord­ing to statistics supplied by NIS Brussels (1975) and LEI Brussels (1975) , the area of dough­dent maize harvested together with the production of maize grain over the last 10 years in Belgium shows the following picture (Table 1).

TABLE 1 AREAS AND YIELDS OF MAIZE IN BELGIUM ( 1 9 6 5 ­ 7 6 )

1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 19 76

Maize area

Forage

5 358 5 913 6 345 6 716 10 655 17 828 24 748 33 287 40 397 49 483 66 018

Grain

450 504 560 7O0 865

1 954 3 265 4 558 4 222 4 879 6 369

— ' —1 (ha)

Total

5 808 6 417 6 905 7 416 11 520 19 782 28 013 37 845 44 619 54 362 72 387 80 000

Maize as

Total forage area

16.3 17.4 18.9 22.8 34.1 52.6 63.6 72.9 80.1 86.2 92.8

percent of

Forage area + leys

2.0 2.2 2.4 2.7 4.3 7.0 10.0 13.8 16.5 20.6 ­

Yield (t/ha)

Total grain crops

1.1 1.3 1.4 1.5 2.4

• 4.3 6.2 8.2 9.3 12.6 ­

Forage

47.3 52.3 53.7 52.6 54.5 52.8 51.0 45.0 43.8 48.0 50.1

Grain

4.46 4.42 4.67 4.50 4.78 5.18 5.63 4.04 6.29 5.Ol 5.88

In 1965. the t o t a l maize product ion (maize forage + maize grain) amounted t o 5 808 ha, by 1970 t h i s area had increased

Communication RW ΛΓ 354 of the above Institute.

168

to 19 782 ha (χ 3.4) and by 1975, maize production had increased to 72 387 ha (x 3.7).

Since the development of precocious hybrids, all Belgian agriculture districts, with probably the plateaus of the Ard­ennes excepted, are suitable for dough­dent maize production.

From the 1.48 million ha of agricultural land in Belgium in 1975, 847 471 ha was destined for direct forage production, 575 892 ha for arable land, 50 454 ha for horticulture and 6 456 ha for other uses. The principal change compared with 1974 concerns the production of dough­dent maize which increased from 3.3% of the total area in 1974 to 4.5% in 1975.

Increased herd size, limited land resources, efficient integral mechanisation from sowing to feeding and high levels of production, undoubtedly promoted maize expansion. Moreover, cattle feeders have become increasingly aware of the excellent forage characteristics of maize silage and its high energy value for ruminant rations. Maize, used as whole plant silage, has a greater energy content than any other forage, fodder beet ex­cepted. When properly ensiled, maize silage is a highly palatable feed which gives high levels of intake by beef and dairy cattle.

As shown in Table 1, maize as a proportion of total forage production (maize, clover, lucerne, fodder rye and kale) increased very sharply from 16.3% in 1965 to 52.6% in 1970 and 92.8% in 1975. Comparing the total area of maize with the total forage area + temporary grassland (leys) we find an increase from 2.0% in 1965 to 20.6% in 1974. The proportion of maize in the total grain crops (maize included) increased from 1.1% in 1965 to 12.6% in 1974.

The change in yield per ha of maize forage and maize grain during the same period (1965­75) is presented in Table 1.

QUANTITIES USED FOR DIFFERENT TYPES OF ANIMALS

Maize can be used in three different forms as a basic feed for dairy and beef cattle: maize silage, dehydrated whole maize plant pellets and high moisture maize grain. We can estimate the amount of high moisture grain given as a high energy basic feed to beef cattle in 1975 as only about 100 ha (588 t) at the most.

169 From the c 66 000 ha forage maize harvested in 1975, only

about 300 ha (15 0O0 t) was dehydrated and pelleted. The great­est quantity, about 3 300 000 t, was therefore ensiled.

In the Flemish country, closely linked with dairy production c 80% of this maize silage is given to dairy cattle and young heifers and only 20% to beef cattle. In the middle and south of Belgium, with its larger farms, 55% of maize silage is, how­ever, given to dairy cattle, while 45% is given to beef cattle. Maize silage is mainly produced on the farms where beef production is carried out. In Belgium, maize silage for dairy production is not exclusively reserved as a basic feed for winter rations. Supplementing dairy cattle at pasture with maize silage, espec­ially in dry summer seasons, is common.

For non-ruminants, high moisture maize grain and crushed maize ears are given to fattening pigs and sows, while maize silage is given to sows. In 1975, about 5 000 ha of milled high moisture maize grain was given to fattening pigs and sows, while 300 ha provided crushed ears for fattening pigs. Only restricted amounts of maize silage are given to sows.

VARIETIES GROWN AND CONSERVATION METHODS

Table 2 presents a survey of the different varieties grown in Belgium in 1975 and 1976. For 1976, the data are based on the quantities of seed sold.

The varieties shown in Table 2 have been tested during the last 3 years for precocity and resistance against lodging (on a scale of 1 to 9) by NDALTP Brussels (1976). All varieties tested are registered on the Belgische Nationale Rassencatalogus (1975) except for the simple hybrid Anjou 196 which is registered on the Europese Rassenlijst (1976) and has not been tested.

As shown in Table 2, the LG, Primeur, Anjou group will con­stitute more than 80% of the land area in 1976.

For maize destined for grain production or to be harvested as crushed ears, LG7 was the most preferred variety. High ker­nel yield, precocity and good resistance against lodging will determine the choice of variety.

For maize destined for ensiling, climatic factors and soil conditions must be taken into account. In the coastal regions,

170 attention is particularly paid to resistance against lodging, whilst on the more dry and warm Campine north east regions, resistance to maize smut fungi (Ustilago maydis) is an important factor. Although no variety is resistant, we must distinguish between sensitive varieties such as Anjou 210, and especially Inra 258, and less sensitive varieties such as LG11 and Dekalb 202.

TABLE 2 VARIETIES OF MAIZE GROWN IN 1975 AND 1976

Variety 1975

ha

LG7 27 LG11 9 Cargill Primeur 170 8 Anjou 210 5 Inra 258 20 Anjou 196 But 234 Fronica

Others* 1

000 500

600

790

270

2 50

000

% of total area

37.3 13.1

11.9

8

28

0.4

1.3

1976

ha

29 12

11

8

7

5 3 3

1

000 000

000

000

000

000 750 500

000

% of total area

36.1 15

13.7

10

8.7

6.2 4.7 4.4

1.2

Preco­city

8 6

7.4

5.4

4.6

early 5.8 5.7

Character!

Resistance against lodging

8.7 8.7

8.4

8.4

8.7

8.3 8.1

sties

Dry matter yield

++ +++

++

++

+

++ ++ +++

* Maris Carmine, Inra 200, Dekalb 202, Leopard, Capella, Prestor.

On the small mixed farms of the Flanders area, the system of growing Italian rye-grass or winter rye before maize is fre­quently applied.

Forage maize is mainly conserved in clamp or trench silos, after chopping in the field to a maximum length of 2 cm, and without additive. The Belgian farmer has been allowed to use NPN sources such as urea and biuret for silage making since February 1974. Price conditions of protein concentrates vs non-protein nitrogen are determining the use of these NPN sources.

171

In 1975 only about 20 airtight silos (Harvestore type) of 500 m were used for ensiling maize. About half were used for ensiling maize forage (14 ha χ 50 t/ha = 700 t/silo); the other half were destined to conserve high moisture maize grain (45 ha χ 6 t/ha = 270 t/silo). In total about 7 000 t of forage maize and about 2 700 t of high moisture maize grain were therefore ensiled in airtight silos. As mentioned before, only about 300 ha (15 000 t) compared with a total quantity of 3 300 000 t of maize silage are dehydrated and pelleted.

QUANTITIES OF MAIZE GRAIN IMPORTED

The direct import of maize from non­EEC countries decreased from c 700 000 t in 1969 to 350 000 t in 1973 (Table 3).

TABLE 3 TOTAL IMPORTATION OF GRAIN AND MAIZE INTO BELGIUM (1 000 t) *

Year

1969 1970 1971 1972 1973

Total importation

Total grain

3 115 4 043 3 866 3 927 4 278

Maize

1 139 1 362 1 504 1 490 1 451

Importation from the EEC

Total grain

1 626 2 252 2 272 3 030 3 372

Maize

450 560 826

1 084 1 107

* Mahieu (1976)

However, 188 000 t imported from non­EEC countries was sup­plied by the Netherlands in 1973. The importation of maize from non­EEC countries, therefore, amounted to c 540 000 t. Besides the Netherlands, France was a major supplier from within the EEC. There has evidently been, for all grains without exception, a great increase of importation from other countries within the Community.

BEEF PRODUCTION SYSTEMS

Maize forage has two important advantages compared with other

172 forages in an intensive beef production system, namely a reason­ably constant digestibility, coupled with increasing dry matter intake with increasing stage of maturity. With other forages, however, harvested as hay or conserved as silage, a decline in digestibility and dry matter intake occurs with advancing mat­urity.

Beef production systems in Belgium with maize as the basic feed are shown in Table 4. There has been a strong tendency towards higher live weights at slaughter over the past few years. The high purchase prices of new-born calves and store cattle, together with better selling prices for heavier animals, of higher meat quality,are responsible for the increased slaughter weight. The production of young intensively fed bulls (baby-beef) with a market weight of 480 - 525 kg therefore remains rather limited.

In the category of fattening bulls, the production of ani­mals with a live weight at slaughter of 525 - 575 kg in 15 - 18 months, is the most common system for larger farms in the middle and south of Belgium. This system is characterised by a period of moderate gain on pasture (4 months) after the initial rearing period. The finishing period starts at 200 - 250 kg live weight.

The production of fattening bulls with a market weight of 575 - 650 kg after 20 - 22 months is more usual on the small mixed farms of Flanders. It differs from the previous system in having a longer pasture period ( 6 - 7 months); the finishing period starts therefore only at 300 - 350 kg.

More details concerning beef production systems in Belgium with other categories of animals are reported by Buysse and Boucque" (1975) .

Fattening bulls in the three systems described, (Table 4) can be fed during the finishing period with either maize sil­age ad libitum, dehydrated maize pellets or high moisture maize grain.

As mentioned before, the use of high moisture maize grain conserved with propionic acid, or of dehydrated whole maize plant pellets, remains rather limited.

Maize is always supplemented with protein rich concentrates at a level of 0.75 or 1% of the live weight depending on the production system used (Table 4).

173 TABLE 4 BEEF PRODUCTION SYSTEMS WITH MAIZE AS THE BASIC FEED

Production system

1. Young bulls (baby-beef) (intensive system)

2.Fattening bulls (semi-intensive)

3. Fattening bulls (semi-intensive)

4. Young steers

Market weight (kg)

480-525

525-575

575-650

c 600

Age (months)

12-13

15-18

20-22

c 24

Basic feed

1.

1. 2.

3.

1. 2.

3.

1.

Rearing period: Maize silage Maize pellets High moisture maize grain Rearing period Pasture period (4 mos.) From 200 - 250 kg Maize silage Maize pellets Hioh moisture maize grain Rearing period Pasture period (6-7 mos.) From 300-350 kg: Maize silage Maize pellets High moisture maize grain Wintering ration: all types of silage incl. maize silage

Concentrates

1% LW (protein rich) NPN-sources

0.75 or 1% LW (protein-rich) NPN-sources

0.75% LW (protein-r ich) NPN-sources

1 kg/day (protein-rich)

In the two semi-intensive systems with fattening bulls, the concentrate can also be limited to 2 kg per day, but consequently maize silage is supplemented with 2 - 4 kg dried sugar beet pulp pellets per day.

The concentrate can also be replaced by urea-N. Ordinarily, 1% of a commercial mixture composed of 50% urea and 50% minerals is added to the maize forage at ensiling.

Maize choppers are sometimes equipped with an apparatus to add the product during chopping in the field.

In 1975 c 1 000 t r.umipec (commercial mixture of 50% urea

174

and 50% minerals) was used by farmers to enrich c 2 000 ha maize silage for its deficiencies of nitrogen and minerals.

The performance of fattening bulls fed on maize silage, de­hydrated whole maize plant pellets or high moisture maize grain is presented in Table 5.

TABLE 5

PERFORMANCE OF BULLS FED WITH MAIZE SILAGE, DEHYDRATED WHOLE PLANT MAIZE PELLETS OR HIGH MOISTURE MAIZE GRAIN

Basic feed

Concentrate level (protein­rich)(%LW)

Number of bulls Initial weight (kg) Final weight (kg) Daily gain (g) Daily feed intake (kg) Concentrate Maize silage Maize pellets High moisture maize

(55% DM)

Feed conversion (kg) Concentrate (7.5 BF*) Maize silage (0.7 BF) Maize pellets (4.75 BF) High moisture maize

(4 BF)

Feed cost per kg gain (BF)

Maize

0.75

• 62 289 572

1 094

3.1 19.3 ­

­

2.8 17.6 ­

­

33.3

silage

1

78 278 566

1 183

4.1 17.7 ­

­

3.4 14.9 ­

­

36.1

Maize pellets

1

72 278 567

1 184

4.1 ­

5.4

­

3.45 ­

4.6

­

47.7

High moisture maize

1

26 277 571

1 408

3.8 ­

­

7.1

2.7 ­

­

5.1

40.7

♦Belgian Francs Beef p r o d u c t i o n r e s u l t s w i t h maize as t h e b a s i c feed a r e

p r e s e n t e d i n more d e t a i l by Poucqué e t a l . ( 1 9 7 6 ) .

175

REFERENCES

Boucqué, Ch. V., Cottyn, B.G. and Buysse,· F.Χ. 1976. Maize silage without or with NPN, dehydrated whole­crop maize pellets or high moisture corn for finishing bulls. In: J.C. Tayler and J.M. Wilkinson (Editors) Maize as a basic feed for beef production. Animal Feed Science and Technology

Buysse, F.X. and Boucqué, Ch. V. 1975. Present and future beef production systems in Belgium. In: J.C. Tayler and J.M. Wilkinson (Editors) Improving the nutritional efficiency of beef production. Commission of the European Communities, Luxembourg.

Gemeenschappelijke rassenlijst voor Landbouwgewassen. 1976. Tweede vol­ledige uitgave. Publikatieblad van de Europese Gemeenschappen. 19° jaargang nr C65 ­ 20 maart 1976.

LEI ­ Statistieken 1975. Landbouw Economisch Instituut, Ministerie van Landbouw, Brussel.

Mahieu, A. 1976. In ­ en uitvoer van plantaardige produkten. Landbouw­

tijdschrift 29:33. Nationale Rassencatalogus voor Landbouwgewassen. 1975. Ministerie van

Landbouw, Brussel. NDALTP. 1976 Nationale Dienst voor Afzet van Land­ en Tuinbouwprodukten.

Ministerie van Landbouw, Brussel NIS. 1975. Landbouwstatistieken. Nationaal Instituut voor de Statistiek.

Ministerie van Economische Zaken, Brussel.

Animal Feed Science and Technology, 1(1976) 177­181 tlscvier Scientific Publishing Company, Amsterdam ­ Printed in The Netherlands

USE OF MAIZE FOR LIVESTOCK FEEDING IN THE NETHERLANDS 177

F. de BOER Institute for Animal Feeding and Nutrition Research "HOORN" Postbus 67, Keern 33, NL ­ Hoorn, The Netherlands.

HISTORY AND AREA

The production of maize in the Netherlands started about 130 years ago. However, results were inconsistent and so the area cropped with maize remained small. A new interest grew some years before and during World War 2. A total area of about 4 500 ha was sown with maize at that time. The main purpose was the production of maize as a grain crop, but occasionally, because of frequently poor harvest conditions, farmers had to make maize silage. Favourable maize­grain prices pushed the area up to about 14 000 ha in 1952. Subsequently a substantial decline in grain prices resulted in the area shrinking down very quickly to about 4 500 ha and at the same time the switch from grain to maize silage began. New strains of maize, modern harvesting and ensiling equipment, more efficient cropping systems caused a re­markable increase in the area sown to maize in the Netherlands from about 1970 until now as is shown in Table 1.

TABLE 1 AREA (ha) OF MAIZE IN THE NETHERLANDS

For maize silage For grain Area for arable crops χ 1 000 ha Maize area as %

1969

4 200 60

720

of arable crops 0.6

1970

6 40O 1 000

686

1

1971

13 200 2 300

679

2

1972

29 5O0 3 800

685

*

| 1973 1

¡50 O0O I 2 900 i i 675

! 8

J.974

73 500 1 900

675­

11

1975

77 500 1 400

675

12

As a result of this spectacular change maize now covers about 12% of the area used for arable crops in the Netherlands and ranks in fourth place after potatoes, wheat and sugarbeet.

178 About 90% of the total maize area is concentrated in the

sandy soil region of the country (mainly in the south and east). Table 1 clearly shows that maize grain production in the Nether­lands ranks far behind the maize silage production, although the increase in grain production has been relatively greater.

VARIETIES AND HARVESTING METHODS

The most popular variety of maize cultivated in the Nether­lands at the moment is LG 11 (1975: 53%) with Capella (1975: 36%) in the second place (Capella was called formerly Caldera 535). Some years ago the variety called Leopard was fairly im­portant.

Only a small percentage of the maize crop is fed fresh, main­ly in emergency situations. The big bulk is harvested and made into silage in the last half of September and the first half of October. There has been a slight interest some years ago in artificial drying of fresh and ensiled maize, but because of ex­cessively high production costs it did not gain popularity.

Fresh maize is cut at the stage of maturity, characterised by the grain being from dough to hard dough stage of ripeness. At that point the most favourable combination of factors, such as dry matter output, content of feed energy (SE), average digestibility, suitability for the ensiling process and for maximum feed intake by cattle, appears to be available. Farmers always try very hard to have maize ensiled with a dry matter content of at least 25%. Of course 30% or higher is preferable. However, climatic conditions sometimes prevent these levels being attained, resulting in a substantial loss of effluent, and consequently loss of feed. Feed­tables from the Dutch Bureau for Livestock Feeding show data for the feeding value of maize silage, (Table 2).

TABLE 2 FEEDING VALUE OF DUTCH MAIZE SILAGE

DM Nutrients in dry matter (g/kg) (g/kg) SE dep Ca Ρ Mg Na

Maize silage 260 600 55 2.5 2.5 1.3 0.2

179 UTILISATION OF MAIZE

Most of the maize silage produced in the Netherlands is fed to dairy cattle. From a rough calculation one may conclude that 90 - 95% of the annual production of maize silage is fed to dairy cows and the remainder to fattening cattle, mainly young bulls.

The gradual, but continual, increase in the size of dairy farms in our country has led to a discrepancy between herd-size and roughage-producing area on the farm. High application rates of fertilisers, very efficient pasture-utilisation etc. allowed many dairy farmers to raise the number of dairy cows per ha up to about 3. Having attained that stage the roughage-part in the winter ration approaches the minimum.

This has led quite a number of (mainly small) farmers on mixed farms (pasture and arable crops) to increase the acreage of maize at the cost of grain crops such as rye and oats. In fact, the area of these two grains, comprising about 150 000 ha in 1969/70 shrunk down to about 50 000 ha in 1974.

Secondly quite a number of farmers have specialised their animal production in such a way (pigs, poultry) that crops from their farm area are not needed for their own enterprise.

A third group of farmers stopped farming (with financial support of the government) but made their agricultural area available for maize cropping.

Especially these two groups of "farmers" sell their maize crop on contract to dairy farmers with large herds of cattle.

There has been a substitution of pasture by maize, but this is restricted to those lots that are located at considerable distance from the farm and its main land-concentration. Pasturing is in such circumstances technically not feasible and so it was decided quite often to grow maize on that area. Moreover, it requires only a minimal amount of farm-labour because in general a contractor will handle the crop completely from seeding through to harvesting.

As mentioned already, maize growing for grain production is relatively unimportant in the Netherlands. Still the amount of maize-grain fed in animal husbandry in our country is large. It is by far the most important grain in the compound feed industry, which produces over 10 500 000 t per year. Maize comprises about

180

23% of this bulk, viz. 2 500 000 t. Assuming an average yield of maize grain of 5 t per ha, this means that the Netherlands are utilising the maize output from 500 000 ha elsewhere (mainly in USA and France) to feed its poultry, pigs and cattle.

FEEDING

Dairy cattle need a fairly high content of protein in relation to energy during lactation. If energy is expressed in starch equivalent the optimal SE/dcp ratio should be about 5 : 1 . In maize silage this ratio is extremely high (12 : 1) requiring special measures in dairy cattle feeding. Therefore the feeding of maize silage as the sole basal diet with concentrates to dry cows, and cows giving less than 10 kg milk per day, is avoided. In these conditions (existing only on a relatively small number of farms) part of the roughage ration has to be grass hay and/or grass silage. These roughages, containing a relatively high protein content, alleviate the extreme energy-protein ratio in the ration and prevent the cows from putting on too much fat. For cows producing more milk, a combination hay/grass silage and maize silage is strongly advised, for the same reasons, and to allow the farmer to use only one type of compound concentrate, with dcp content of about 18%.

In rations for dairy cattle, maize silage is generally fed together with at least 2 kg dry matter from hay or (wilted) grass silage, to prevent low milk fat contents and feed refusals.

Young fattening bulls are increasingly being fed on maize silage as the most important part of their ration after 3 months of age. In general it is still a combination of grass hay and/or grass silage with maize silage, supplied with increasing amounts of a compound feed as the end of the fattening period approaches. However, utilisation of maize silage as the only feed for young fattening bulls is increasing. About 25kg maize silage and 2-4 kg concentrates, rising during fattening can serve as an average example of a ration which enables young bulls to gain about 1 100 g daily. In fact the specialised bull fattening units are based on maize growing and maize silage feeding. The bulls are slaughtered at about 15 - 16 months of age.

181 Utilisation of maize silage as a roughage for breeding sows

is gaining more interest nowadays in the Netherlands. Large sow units combine two advantages in this way: they economise on the purchase of concentrates and they alleviate their problems of pig manure production by fertilising the maize crop heavily with the manure. In this way large-scale pig farming can, at least, partly avoid the risk of being a potential polluter.

The necessity to supplement maize, because of its very low content of protein (and mineral), with protein-rich concentrates has led to much research work to find alternative sources of supplementary Ν for ruminants. So urea is fed occasionally in the Netherlands, especially when protein prices are high, as they were a few years ago. If it is applied it will be fed mainly to fattening young bulls, while protein-rich conserved feeds from pasture will remain important in dairy cattle rations.

Some experience has been gathered by applying a urea-mineral mixture, added mechanically to the maize while being harvested (about 1 000 ha). The percentage of urea added was about 0.5% per kg fresh maize. The results obtained in feeding this type of "high-N" maize silage were promising. However, recent research results in fattening trials suggest that protein requirements of young fattening bulls are substantially lower than was assumed until now. So the need for urea in the Netherlands seems to be smaller than that indicated by the former feeding standards.

Animal Feed Science and Technology. HÌ916) 183-186 183 Elsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands

MAIZE AS A FORAGE CROP IN DENMARK

KR. G. MØLLE Statens Forsøgsstation, Ødum, DK 8370 Hadsten, Denmark

ABSTRACT

Owing to climatic conditions, grass, legumes and root crops have for years constituted the basic forage plants in Denmark. Maize growing has often been attempted, but even now, after the development of several new cultivars, crops of silage maize can only be grown satisfactorily in some southern and eastern parts of the country.

INTRODUCTION

For a very long time, legumes, grass and different root crops have been grown and utilised as basic forage plants. In the course of the last 3 to 4 decades, fodder sugar beet has become the most important forage root crop.

These forage crops are rather well suited to the climatic conditions of Denmark. In order to examine the possibilities of other forage plants, The Danish State Research Institute in Plant and Soil Sciences has carried out trials with new culti­vars of maize. The extension service working with research organisations also has, at intervals, done experimental work to elucidate whether or not maize could be grown successfully in Denmark. Farmers, too, have occasionally tried to grow maize.

Since about 1970 the interest in growing maize has been in­creasing, and the experimental work has correspondingly inten­sified.

MAIZE AREA

The acreage of maize in Denmark is negligible. Estimated on the base of seed sold, about 1 500 ha of silage maize may be grown in 1976. For comparison, data are given in Table 1 of the areas of other crops in Denmark.

184

TABLE 1 CROPS GROWN IN DENMARK

Crop

Barley Other cereals and pulses Root crops Potatoes Grass and green fodder in rotation Permanent pasture Seeds, other crops and fallow

Total arable area of farms (1974)

1 000 ha

1 437 303 248 33

469 277 138

2 905

Percent of total

49 10 9 1 16 IO 5

100

Source: Danmarks Statistik, 1975.

In years with an exceptionally mild and favourable growth season, it has been possible to obtain nearly ripe maize in the south-eastern part of Denmark. However, if maize has a real chance in this country, only maize grown for silage or green fod­der could reasonably be taken into consideration.

YIELD OF MAIZE

At present the Danish State Research Institute in Plant and Soil Science annually tests 15 - 20 cultivars of maize and 4 cultivare were registered in the Danish List of Cultivars of Agricultural Crops 1975. Table 2 shows average results from trials carried out over the period 1972/74.

The variations in yield from year to year and between local­ities demonstrate that the northern limit for successful pro­duction of silo maize passes through Denmark.

By comparison, the normal dry matter yield of grass adequately fertilised with nitrogen for the years 1972 - 74 averaged 12.8 and 10.6 t at Rønhave and Ødum respectively.

As a whole, the yield levels shown in Table 2 are not unequivocally higher than the yield level obtained in trials carried out with other maize cultivars 15 - 20 years ago, apart from the locality Ødum where the climate is cooler than that of Rønhave.

18S TABLE 2 YIELD OF DRY MATTER (t/ha)

Year or locality

1972 1973 1974 Average: 1972 - 74 Rønhave (Southern Jutland) Ødum (Eastern Jutland)

Cultivar

Anjou 210

9.4 12.2 8.0 9.8 11.4 7.9

LG 7

9.3 12.6 8.0 10.0 11.5 8.1

LG 11

9.9 12.9 9.1 10.6 12.1 8.5

CapeIle

9.4 13.4 8.4 10.4 12.3 8.4

Reference: Pedersen, 1975

MAIZE VARIETIES

Until now the goal for attempting maize growing has been to achieve a crop with a dry matter content of about 30% in order to produce silage of high quality and without effluent loss. This dry matter content presupposes a rather well developed ear, and the goal is seldom reached. Very often the dry matter con­tent of the whole crop lies between 20% and 25%.

Of the cultivars mentioned in Table 2, Anjou 210 and LG 11 have received most attention, but this year the cultivar Fronica has been especially in demand.

As mentioned, maize has until now been regarded as a silage crop. However, trials have been initiated to elucidate whether maize could be advantageously grown and utilised as a stall-fed forage crop from early August. For this purpose the dry matter level would be relatively unimportant and the most important question is whether or not the crop can attain a reasonably high yield of dry matter, the quality of which, when harvested day by day over a period of 1 to 2 months, is high and uniform. It is an open question whether there is likely to be a demand for maize for silage and maize for stall-feeding in the future. If there is, then two types of maize will be required in Denmark, a type giving a relatively well developed ear, and a type pro­ducing a high yield of vegetative mass.

186

IMPORTATION OF MAIZE

The main proportion of imported maize comes from North Amer­ica. The yearly imported quantities are small, and chiefly used in feed mixtures for chickens. The total amounts of cereals and of maize used for livestock feeding are illustrated in Table 3.

TABLE 3 CEREALS GIVEN TO LIVESTOCK, 1964 ­ 1974

Five­year period

1964/65 ­ 1968/69, 1969/70 ­ 1973/74,

average average

1 000 t

Cereals, total

5 393 5 801

Maize

170 232

Maize as percent of

total

3.1 4.0

Source: Danmarks Statistik, 1968­75.

REFERENCES

Pedersen, Κ.E., 1975. Sorter af majs til grr/nhi/st. 1237. meddelelse fra Statens Forsøgsvirksomhed i Plantekultur.

Danmarks Statistik, 1968­75.

Animal Feed Science and Technology, 1 (1976) 187-193 187 Elsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands

PROSPECTS OF GROWING MAIZE IN FINLAND

S. PULLI, E. POUTIAINEN and LIISA SYRJALA Department of Animal Husbandry, University of Helsinki, 00710 - Helsinki 71, Finland.

Maize has been studied in Finland during several periods. Virtanen (1938) worked with maize in the 1930's. His experience was positive and encouraging. At the Agricultural Research Centre in Tikkurila near Helsinki, results obtained in the 1950's were disappointing, owing to drought and early autumn frosts. In 1962, rainy and cold weather did not favour the growth of maize and research workers concluded that maize was not a suitable crop for Finnish growing conditions (Yllo, 1962).

Maize research received a new impetus from the spectacular results of Mr. G. Brüninghaus on his private farm in South West Finland. In 1974 the Finnish Maize Committee was founded to sponsor maize research in Finland once more. The new start of maize research was also spurred on by the new, high yielding varieties and new cultivation techniques developed in maize growing countries.

At the moment, the cultivated area occupied by maize in Finland is tiny. Maize cultivation is mostly confined to South West Finland and is practised on beef cattle farms. The cultivated area is 40 - 50 ha.

MAIZE AND SOLAR RADIATION IN FINLAND

The amount of available radiation is very important for the growth of maize. At the beginning and in the middle of the summer, the maximum value of the light intensity in Southern Finland is about 100 000 lux and in August is still 85 000 lux. These values show that the amount of light is not the limiting factor for the growth of maize.

TEMPERATURE CONDITIONS IN FINLAND

The factor limiting the growth of plants in Finland is

temperature rather than light. Eritish research results show that forage maize needs 728 accumulated degrees Centigrade to give economic returns,· this figure being the number of degrees above 10 C aggregated over the growing seasons. Grain maize needs an average of 762 accumulated degrees over the same period to produce mature grain at 40% moisture. These values are reached in only a few parts of Finland, and then not in every year. For instance, the 197 4 - 75 average for the accumulated degrees from May to September in Tikkurila were 594 C. However, in Finland the long summer days can compensate for the low temperature sum. Maize is supposed to require about 900 hours of light for matured grain, and we have 1200 -1300 light hours available during the growing season.

In Southern Finland, the growing season is 175 - 180 days long. The mean temperature of the whole growing season is 12.6 C. The mean temperature from June to August is 15.7 C, enough for the succesful growth of maize. The most critical factors are the spring and autumn frosts. The spring frost can be avoided if seeding is delayed until May 15 to 25. August frosts are very rare, but the occurrence of frost in September is 20 - 30%.

THE WATER REQUIREMENTS OF MAIZE

The most severely limiting factor for maize growth in Finland is lack of water during the early summer. The results of various studies show that 450 litres of water are needed for every 1 kg of dry matter produced. In the United States, for instance, this corresponds to 400 - 625 mm rainfall per month. The lower mean temperatures in Finland cause lower water requirements here. The objective, however, is 100 mm rainfall per month, which is not achieved in Finland. In Tikkurila, for instance, the average rainfall for 1971 - 74 during the growing season was 272 mm and the distribution of the rainfall was not the best possible.

In Finland, the usual 25 - 50 mm of rain during the flowering period of maize is inadequate, since over this period the plant uses almost half of the water required for its entire growth and development. The dry period in the

TABLE 1 MAIZE VARIETIES IN SOUTHERN FINLAND IN 1975 (280 VARIETIES IN THE TRIALS)

Variety

Limagrain 775007 672508 LG 5

" LG 11 LG 7

Inra 176 Cargil 170 Princus

Height (cm)

260 275 265 250 250 205 205

2 Plants/m

6.8 6.6 7.4 6.5 6.5 4.0 4.0

DM (%)

26.4 28.0 27.4 25.5 27.2 26.3 23.3

Whole crop DM (kg/ha)

10 041 11 026 11 485 11 419 10 209 5 780 8 657

Matured grain yield (kg/ha; 15% moisture)

4828 4955 5550 5580 4660 3280 3930

Protein (% of DM)

Average of seven varieties

Whole plant

8.4

Leaves and stalk

7.8

Whole ear

9.4

Grain

11.3

190 early summer in Finland means that maize must be irrigated.

PRELIMINARY RESULTS WITH MAIZE AND SORGHUM

The Finnish Maize Committee conducted preliminary trials with sweet corn and sorghum in 1974. In 1975, the trials were broadened to include maize, sweet corn and sorghum. The main part of the trials was run in Viurila, South West Finland, where 280 maize varieties, 30 sweet corn varieties and 14 sorghum varieties were grown and several experiments made to determine the appropriate management techniques. Maize trials

In Viurila, 40 varieties out of 280 produced completely matured seed in 1975. The year was extremely dry but a little warmer than usual. In late May, the crop experienced a rare -8 C frost. The autumn was warm and long, and favoured the growth of maize until the beginning of October. In Table 1 results for some of the best varieties in the trial are presented. In the preliminary trials, the French varieties appear to be best adapted to our growing conditions, although some Hungarian, Yugoslavian and Russian varieties are also promising. However,Dutch and British varieties seem to have difficulties in adapting to our continental growing conditions. Sweet corn for silage

Sweet corn has a relatively short growing time, and under our long day conditions it seems quite able to produce not only a good ear yield, but also a good stalk and leaf yield for silage. In Table 2, the results of sweet corn trials are shown for 1974 - 75. Varieties such as North Star and Spring Gold with a long vegetative phase have a relatively high silage dry matter yield and a low matured ear yield. Golden Beauty seems to have both yield components in satisfactory measure. Also the protein yield of sweet corn silage has considerable feeding value. Sorghum varieties in the trials

Sorghum has been tested during 1974 - 75. The preliminary results show that most of the varieties tested have a good dry matter yielding ability. Although the protein content of all the varieties is relatively low, the protein yield per unit

191

area is high, because the dry matter yields are high. The sorghum-sudan hybrid Grazer shows the best ability to grow in Finland (Table 3 ) . Beefbuilder is clearly too late under our growing conditions. Sorghum cannot produce matured seed in Finland.

TABLE 2 SWEET CORN VARIETIES IN 1974-75 IN SOUTHERN FINLAND

Variety

Buttervee Seneca - 60 Golden Beauty Sunnyvee Spring Gold Early Alberta North Star

Matured ear yield (kg/ha)

7 974 7 717 7 547 6 943 5 127 3 220 3 298

Matured ears (%)

77.7 89.6 69.4 86.4 56.8 49.1 42.1

Stalk and leaves DM (kg/ha)

4 70O 5 490 6 631 4 545 7 007 5 670 6 886

DM (%)

16.9 15.7 17.8 17.1 19.0 17.0 17.0

Protein (% DM)

11.9 12.1 12.9 12.3 11.7 11.8 12.1

TABLE 3 SORGHUM VARIETIES IN 1974-75 IN SOUTHERN FINLAND

Variety

Beefbuilder

Grazer

Astro

Seeding rate (kg/ha)

20 30 40 20 30 40 20 30 40

DM yield (kg/ha)

9 600 10 640 11 850 12 440 12 890 14 850 10 540 11 830 12 370

DM (%)

19.1 19.8 20.6 20.8 21.1 22.1 22.5 22.6 22.6

Protein (% DM)

11.0 10.6 9.8 10.1 9.9 8.7 9.6 9.6 10.0

192 MAIZE SILAGE FEEDING TRIAL

A preliminary feeding trial in farm conditions was arranged in 1976. It lasted two months and consisted of 60 beef animals, age 4.5 - 5.5 months at the beginning of the trial. The growth rate of the Ayrshire bulls before the trial was 700 g per day. Animals received maize silage ad libitum and an additional amount of concentrates containing 1.5 feed units with 218 g of digestible crude protein per feed unit. Dry hay was given at the rate of 0.2 FU per day. During the first feeding month, the 60 animals gained at an average rate of about 490 g per day and during the second month at about 650 g per day (Table 4) The average growth rate per animal during the whole test period was about 570 g per day. This relatively low value for the daily growth rate can be explained by the cold weather during the test period, as the animals were kept in a barn without walls. The other reason was the low proportion of ears in the silage dry matter caused by too dense a population and a relatively late seeding time.

TABLE 4 MAIZE SILAGE FEEDING TRIAL

Weight class

- 120 kg 121 - 140 kg 141 - 160 kg 161 - kg

Number of animals

14 22 14 10 60

Daily growth rate (g/day/animal) Dec 30 - Jan 30

431 434 566 597

Ave. 491

Jan 31 - March 1

578 651 655 723 647

Ave.

504 539 612 631 568

CONCLUSION

Maize and sorghum are sub-tropical C-4 plants with a high dry matter yielding ability. Maize is relatively well adapted to southern and central Europe. In preliminary tests in Finland, from 1974 -75, the results have been successful and

193

encouraging. Maize for silage can be grown in Southern Finland in relative safety in years free from August frost. There is a need for vigorous maize varieties adapted to more continental growing conditions. Sorghum has produced high dry matter yields and shown a good ability to utilise our growing season. If the spring start of the growth of maize and sorghum could be hastened by irrigation and other management practices, these species would produce higher dry matter and FU yields than other grasses and with relatively high security.

REFERENCES

Virtanen, A.I. 1938. Kokemuksia maissin ja maissi-peluskin viljelyksestä maassamme. Karjatalous: 8

Y11Ö, L. 1962. Maissin viljelykokeista Suomessa. Maatalous ja koetoiminta XVI: 101 - 110.

FURTHER INFORMATION MAY BE OBTAINED FROM:

Leonard, W.H. and Martin, J.H. 1963. Cereal crops. McMillan Company. New York, USA.

Owen, F.C. 1967. Factors affecting nutritive value of corn and sorghum silage. Journal of Dairy Science 50: 404 - 416.

Thomson, A.J. and Rogers, H.H. 1968. Yield and quality components in maize grown for silage. Journal of Agricultural Science, Cambridge 71: 393 - 403.

Voldeng, H.D. 1971. Factors affecting the growth of Zea mays. L.D. Phil. Thesis. Oxford University, England.

Animal Feed Science and Technology, 1(1976) 195-198 195 Elsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands

THE CURRENT SITUATION REGARDING THE USE OF MAIZE IN IRELAND

F.J. HARTE The Agricultural Institute, Grange, Dunsany, Co. Meath, Ireland

ABSTRACT

In Ireland, maize growing on a commercial scale started in 1970 though there were various attempts to grow it experiment­ally before that time. The area used for maize production rose to a maximum of 1 200 hectares in 1973 but has now apparently stabilised at approximately 400 hectares. Low temperatures have militated against consistent yields and it is felt that most of the country is unsuitable for growing the present varieties of maize. Maize, therefore, will not make any worthwhile contri­bution to cattle production in Ireland unless a variety can be found that will grow at lower temperatures (in May and September) than those now available. This is a challenge to the plant breeders.

AREA SOWN

The area of maize grown in Ireland is now approximately 400 ha per year and maize growing only started on a commercial scale in 1970. There were 1 200 hectares in 1972 and the de­cline in area seems to have been due mainly to the failure to get consistently good production results each year. The total area of forage crops is approximately one million ha while the area under grain crops is 240 000 ha. The total land area under crops and pasture is 4.85 million ha and the total cow population (dairy and beef) at present is approximately 2 million. I list cow numbers because they are the basis of our cattle production, and since we are capable of producing maize silage only, it must be utilised by ruminants.

Our Institute started a comprehensive maize programme in 1971 which is now nearing completion (Neenan, 1976). Over 40 varieties have been examined at our Research Centre at Oakpark, and all of them are sensitive to early and late season low temp­eratures. About 50% of the commercial maize grown is Cargill

196 Primeria 170, 40% is from the varieties Anjou 210 and LG 11, and 10% is Caldera 535. However, maize varieties used are often influenced by commercial pressures particularly when the level of interest in the crop is not high. It was also found we needed higher plant densities than those recommended in countries with warmer climates.

YIELDS

The yield has varied very much with season from 6.0 to 12.5 t DM/ha. The crictical point in degree days appears to be 550, and as an indication of our varying temperature, the degree days figure for 1972 was 527, while last year it was well above 800. It is interesting to note that in the growing season, the highest temperature in Ireland is equal to the lowest temperature in Holland, where we know there has been a great expansion in maize production. In Ireland, there is a 10% chance of frost occurring in May and again in early October.

MAIZE FOR SILAGE

The minimum dry matter concentration for ensiling maize is 20%. In Ireland, maize increases in DM content about 1% in every 10 days from September onwards but maximum dry matter production is achieved by September. No maize is grown to maturity. Harvesting can be a problem in late autumn owing to wet soil conditions. In good years, the ear contributes 40 -50% to total DM. There always has been, as might be expected, a close relationship between DM content of the plant and total DM production in any one year.

BIRD PROBLEM

It should be mentioned that birds, mainly rooks (Corvus frugilegus) are a great problem at sowing time, and of course if the seed is taken by birds, the land cannot be used for other crops that season because of the type of weed control used for the maize crop. No really effective bird control system has been devised.

197 FEEDING EXPERIMENTS

Maize silage has been given almost exclusively to beef cattle. Feeding experiments have been carried out by our Institute to investigate

a) the performance of cattle on maize silage, b) the effects of adding different sources of nitrogen, c) the relative value of maize and grass silages. The mineral content, particularly sodium, is sub-normal

and supplementation is needed. Supplementation with a protein source is necessary and here soyabean meal gave the best results.

When grass silage and maize silage were compared (and it will be appreciated that it is difficult to make a direct comparison), the results shown in Table 1 were obtained.

TABLE 1 COMPOSITION OF MAIZE AND GRASS SILAGE, AND PERFORMANCE OF CATTLE

Silage

Maize Grass

Composition Crude DMD

protein (%) (%)

8.8 69.0 10.3 77.1

DM Intake (kg/day)

8.23 8.88

Performance Average

dally gain (kg)

0.66 0.84

PRESENT RESEARCH AND THE FUTURE OF MAIZE

With the exception of a very small area on the south and south west coasts, the climate in Ireland is not suitable to ensure satisfactory production each year from maize. The situation could readily change if a maize variety were produced which would grow satisfactorily at 2°C lower (i.e. 8°C) than is at present available. It is estimated that maize would need to be consistently capable of producing 12 t DM/ha annually to ensure its competitiveness with grass and fodder beet. Further research on production, and feeding experiments on maize are now suspended until a suitable variety for our climate becomes available.

198

REFERENCE

Neenan, M. (ed) 1976. Fodder Maize, A Status Report, Agricultural Institute, Dublin, Ireland.

Animal Feed Science and Technology, UW b) 199-214 199 Elsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands

THE USE OF MAIZE FOR LIVESTOCK FEEDING IN THE UNITED KINGDOM

J.B. KILKENNY Meat & Livestock Commission, Queensway House, Bletchley, Milton Keynes, Buckinghamshire, U.K.

ABSTRACT

The area of grain maize grown in Britain is insignificant at about 1 000 ha and, in fact, has declined slightly over recent years; there is unlikely to be much of an increase in this area in the foreseeable future. Conversely, the area grown for silage has increased by 700% since 1971 and is now around 27 000 ha. The area suitable for growing maize silage includes the south and east of England, much of the midlands and sheltered sites in Wales and the south west. Two thirds of the maize area is in the south east and east of England. The yield of energy per ha is 107% higher than for barley grain and there are approximately 1 million ha of barley in the south east and south west of England that could potentially be replaced by maize silage.

The average yield in Britain is about 10 t dry matter (DM) per ha (at a DM content of 24%) . The average farm area grown for maize silage is about 10 ha. A high proportion of the crop is harvested by contractors and the most popular varieties are LG11, Dekalb 202 and Caldera 535.

Most of the maize silage produced so far has been given to dairy cows, although the recent trend is for more to be given to beef cattle. Because of the small farm areas of maize, in many cases the maize silage has been fed in combination with other feeds. Even in mixed rations maize silage has significantly reduced the cost of feed per kg of gain compared with more traditional feeds.

Maize silage can be fitted into a whole range of beef systems in Britain. Much of the beef in Britain is produced from grass/cereal systems with cattle slaughtered between 18 months and 2 years of age, and the average concentrate require­ment over the animal's life is about 0.9 tonnes, much of which is in the form of barley which could be replaced by maize silage. Maize silage could be given in the winter in combination

200 with grass silage or hay. Development work is required in this field to consider the implications of reducing the requirement for grass conservation on the overall grazing management system for beef cattle.

The most exciting prospects are, however, where maize silage is used as the main feed for indoor systems of beef production. The two most likely applications in Britain are a feedlot system starting with the reared dairy-bred calf (i.e. a replacement for barley beef) and the winter finishing of suckled calves and stores (i.e. a replacement for traditional feeding based on hay, straw and concentrates).

INTRODUCTION

In the UK, livestock account for 65 - 70% of the total value of agricultural output. Most farms with beef cattle and sheep have a fairly high degree of self sufficiency in feeding-stuffs, but dairy, pig and poultry production depend very heavily on purchased feeds. Since the 1960s there has been a substantial increase in the number of stock, and particularly, of beef cows (104%).

Grass and forage account for approximately 82% of ruminant feed. The proportion varies from 67% for dairy cows to over 90% for beef cows, store cattle and sheep.

Manufactured compound feeds represent about 55% of farmers' total usage of concentrates. The difference represents home grown cereals, mainly barley, which are retained for use on farms.

Of the 2\ million tonnes of grains imported into the UK for feeding,approximately 2 million tonnes are grain maize. In addition a further 800 000 tonnes of grain maize are imported for starch and glucose production and 700 000 tonnes for whisky distilling. Thus the growing of more grain maize in the UK would have a direct import saving role. The development of earlier varieties means that the south and east of England can be considered to be just inside the northern limit of the crop for grain. The area suitable for silage maize is, however, much wider.

201

Newcastle . . „

Grain and ground ear maize

\ ^ \ Silage maize

Silage maize if sheltered

■55" Ν

54' Ν

53 Ν

52 Ν

51 Ν Ashford

0 miles

Figure 1 Areas suitable for grain and silage maize in Britain Compiled by the Meteorological Office. Source: Wye College Maize Unit 1975

Maize Grower's Handbook

TABLE 1 AREA SOWN TO MAIZE IN ENGLAND AND WALES (ha)

Silage Grain

Total

Silage as % of total

1971

2 047 1 250

3 297

62

1972

3 559 2 137

5 695

62

1973

6 674 1 097

7 771

86

1974 .

15 948 1 057

17 005

94

1975

26 020 893

26 913

97

Source: Agricultural Statistics. Ministry of Agriculture, Fisheries and Food

202

AREA AND RELATIVE YIELD

The map shown in Figure 1 indicates areas suitable in Britain for grain, ground ear maize and silage maize.

Although the areas on the map are those likely to be the most successful sites, Ministry of Agriculture returns show that maize silage is grown in almost all counties in England. The breakdown of the silage area by regions is as follows:

South east 28% South west 14% Eastern 35% East midlands 5% West midlands 5% Yorkshire S Lancashire 8% Northern 3% Wales 2% Table 1 gives the total area sown to maize since 1971 (700%

increase). The figures clearly show that the expansion of the maize

area in the UK is entirely due to maize for silage. Despite the rapid expansion, maize as a forage crop is still

in its infancy in the UK. However, results obtained over the past 10 years encourage the belief that consistently high yields can be obtained over considerable areas in England. As the crop is extended into cooler areas the risks must increase and yields will be less than those obtained in southern parts of the country, though careful site selection can compensate for increase in latitude. Whether or not these lower yields of wetter material are acceptable will depend on the alternative feeds and their relative costs. Table 2 gives some details of average yields and costs of feeds in Britain.

The area sown to grain maize has declined after the except­ionally poor growing season in 1972 and is likely to be confined to the most favourable areas of south east England until earlier varieties become available. Ground ear maize and corn-cob mix are possible alternative methods of harvesting the crop in the areas suitable for grain maize production.

The bulk of the UK maize crop is grown for ruminant feeding. For most ruminant stock the yield of energy/ha is generally

TABLE 2 APPROXIMATE YIELD AND COSTS OF VARIOUS FEEDS IN THE UK0

Barley Swedes Turnips Grass silage (average quality) Hay (average quality) Dried grass Grass for grazing Maize silage Mineralised urea Extracted soya bean meal Decorticated groundnut cake Linseed cake Fishmeal

Yield (t/ha)

4.3 60.5 58.0

33.0

6.5 12.5

37. ld

44.0

--

---

Yield of DM (t/ha)

3.7 7.3 5.2

7.4

5.5 11.3

7.4 9.7

--

---

Yield of ME° (MJ/ha)

50 690 93 440 58 240

66 600

46 750 119 780

87 320 104 760

--

---

Costs Variable costs

1.0O 0.52 0.59

0.66

0.70 1.64

0.40 0.68

--

---

(E/1000 MJ ME) Costs of production

2.50 1.14 1.30

2.90

1.40 5.77

0.50 2.12

--

---

Market price

5.40 4.63 -

5.60 7.50

2.00e

-

--

---

Digestible crude protein

(kg/ha)

303.4 664.3 379.6

754.8

214.5 1 536.5

1 369.0 679.0

— -

---

Costs (£ Variable costs

0.17 0.07 0.15

0.06

0.15 0.11

0.03 0.10

--

---

per kg of protein) Costs of production

0.42 0.16 0.20

0.26

0.31 0.39

0.03 0.33

— -

1v— --

Market price

O.90 0.65 -

.

1.30 0.51

0.12 -

0.05

0.28

0.31 0.46 0.29

a Figures are averages for two years 1974 and 1975. Yields and costs of feeds based on MLC records plus published information from ADAS, Universities, MMB. b Metabolisable energy, a Variable cost plus fixed costs but excluding rent of land. d Based on the number of livestock unit grazing days in MLC Grassland Recording Scheme. e Cost of renting grassland.

204 the most important economic factor in a comparison of alternative feeds. It is for this reason that maize silage is increasing in popularity, since it produces 107% more energy per ha on average than barley grain, and 57% more than grass silage (Table 2). Additionally, the yield of energy as livestock feed per ha decreases as the proportion of the crop ensiled decreases (Fig.2).

αϊ en

a o

c"0/,v

>*/:

u 111 4J JJ 111

fi >. M

Ρ

riP

t i C Cl) 4J C O υ

CKOIINI) KAR ΜΛΙ7.Η 30 H.r. 40

1 I L_ I M N - C U I I MIX 41) 4.Ί

_ | L 4(1 4 5

_J l_

10 20

SKI'TKMHF.R 111 211

OCTOHF.K

Figure 2 Dry matter yields and relative maturity dates for different maize products. Source: Wye College Maize Unit 1975. Maize Grower's Handbook.

205 WHAT CROP DOES MAIZE SILAGE REPLACE?

This decision at the farm level can only be made after detailed planning of the whole farm system. Nevertheless the replacement of barley grain by maize silage has a significant effect on the true stocking requirements of livestock systems and profitability. The average 18 month beef animal consumes 760 kg of barley grain in its life time and thus requires approx­imately 0.2 ha of arable land per head in addition to the grass­land stocking rate. The equivalent amount of energy could be produced by 0.08 ha of maize silage. Further comparisons between barley grain and maize silage costs and yields are given in Table 2, and a comparison between feedlot systems for beef production based on barley grain or maize silage is shown in Table 3. Such comparisons need, of course, to be treated with caution but it can be seen that only a modest yield of maize silage (4.2 t DM/ha) is required to 'break even' in terms of physical output with barley grain.

TABLE 3 DIFFERENCES BETWEEN MAIZE SILAGE AND BARLEY GRAIN IN A FEEDLOT SYSTEM OF PRODUCTION

Feed conversion ratio (kg DM/kg LWG) Age at slaughter (months) Crop yield (t DM/ha) Liveweight gain (kg/ha) Stocking rate (animals/ha at 410 kg slaughter weight)

Maize silage

5.7 14 9.7 1702

4.6

Barley grain

5.4* 12 3.7 685

1.9

MLC top third results

The choice between grass or maize silage is more complex. For any particular farm there will be advantages or disadvantages of growing one or the other. In areas of cooler temperatures and with no lack of rainfall, grass will be the normal choice, and in areas of higher temperature and where low rainfall restricts grass production, maize will be attractive. Undoubtedly, maize

206 is an easier crop to ensile and it is much less variable in quality than is grass silage. Good grass silage is as good as average maize silage but too few British farmers make good grass silage. Clearly there are areas where a combination of grass and maize for silage will be appropriate and indeed for some situations this will be a better solution than exclusively growing maize or grass for silage. In the case of beef cattle, however, the reduced requirements for grass silage in the winter can complicate grazing management. Most grass silage has more than sufficient protein for finishing beef cattle but is deficient in energy, (i.e. the opposite to maize silage which is low in protein but is a high energy feed).

Much of the increase in area of maize silage has been, and will tend to occur, in arable areas where the crop can also be used as an effective break crop in the arable rotation. There are approximately 1 million ha of barley in the south east and south west of England that could be used to grow maize silage.

The importance of yield has already been mentioned and the relationship between yield, stocking rate and liveweight gain per ha is shown in Table 4.

TABLE 4 THE EFFECT OF YIELD OF MAIZE SILAGE ON STOCKING RATE AND LIVEWEIGHT GAIN PEK HA AND ON COSTS OF PRODUCTION

Yield of maize silage (t DM/ha)

8 9 10 11 12 13

Liveweight (kq/ha)

FCRa 5.7 : 1

1403 1579 1754 1930 2105 2281

gain

6.7 : 1

1194 1343 1493 1642 1791 1940

Stocking rate animals/ha

5.7 : 1 6.7 : 1

4.5 3.9 5.1 4.3 5.7 4.8 6.2 5.3 6.8 5.8 7.4 6.3

Costs (E/1000 MJ ME)

Variable Cost of* costs production

0.83 2.57 0.74 2.28 0.66 2.06 0.61 1.87 0.56 1.71 j 0.51 1.58 !

a Feed conversion ratio b Variable costs plus fixed costs but excluding rent of land.

207 Yield is also important in relation to the unit costs of

feed. Table 2 shows the cost of maize silage at an average yield of 44 t/ha and Table 4 also shows the effect of different yields on the cost of maize silage. Maize silage is an expensive crop, and recent work has looked at ways of reducing the cost of production. An important development has been the use of slurry to replace inorganic fertilisers, which reduces the variable costs of growing the crop by about a quarter.

SILAGE MAKING IN BRITAIN

The average area grown for maize silage on British farms is about 10 ha. This represents a marked increase over the last five years as more producers have become committed to the crop. There is still a very wide range in the area grown on individual farms, ranging from small plots of less than 2 ha where farmers are 'experimenting' with the crop, to individual farmers who have been growing the crop for 10 years or so with areas in excess of 40 ha.

As digestibility remains constant for a long period (Figure 2) the crop is ideal for contract harvesting. A recent survey recorded that 40% of the surveyed crops were harvested by a contractor; the area of maize grown on these farms was less than half the area on farms where the farmer used his own machinery.

Nearly all the maize silage made in Britain is put into bunker type silos. In the ICI/MDA survey* about two thirds of all crops were ensiled in bunkers, and buckraking was the most common handling method. Although maize silage can be easily handled in or out of tower silos the dry matter content of much of the silage (Table 5) is too low to be suitable for towers because of the high quantity of effluent produced. This is in addition to considerations based on the relative costs of tower and bunker silos.

Table 5 gives details of average yields and composition of typical maize silage in Britain and some indication of the very wide variation in yields and composition is also given. Import­ant reasons for the wide variation in yields are site, seed bed preparation, plant population and variety. *Survey of 166 farms carried out jointly by Imperial Chemical Industries Ltd. (ICI) and the Maize Development Association (MDA) in 1975.

208

TABLE 5 TYPICAL YIELDS AND COMPOSITION OF BRITISH MAIZE SILAGE

Yield, fresh weight (t/ha) Dry matter (%) Dry matter yield (t/ha) Digestible organic matter (% DM) Metabolisable energy (MJ/kg DM) Crude protein (% DM)

Average

40 24.0 9.7

68.0 10.8 9.0

Typical between

22 -20 -5.5 -

65.0 -9.9 -8 -

range farms

55 30* 14.0 72.0 11.8 11

* Large year to year variation, e.g. 1974 average 21.4%, 1975 27.3%

The varieties of forage maize recommended by the National Institute for Agricultural Botany (NIAB) are shown in Table 6. The most popular forage varieties are LG11 DeKalb 202 and Caldera 535.

Most of the maize silage produced to date in Britain has been given to dairy cows rather than beef cattle, although the trend indicates that a higher proportion is now being given to beef cattle. This is partly a reflection of the areas in which most of the maize silage has been grown until now and the relative profitability of beef and dairy production, particularly when capital investment is necessary.

MAIZE SILAGE FOR BEEF PRODUCTION IN BRITAIN

Most of the maize silage given to beef cattle up to date has been given in conjunction with other feeds. This reflects partly the need to establish confidence in the feed by individual farmers and also many of the farmers initially have grown only limited areas of maize silage in relation to their requirements for cattle feed.

The main nutrient deficiency in maize silage for beef cattle is that of protein. Alternative methods of protein supplementation of maize silage for beef cattle are available and there is scope for reducing the costs of the ration by using non-protein nitrogen (NPN). Protein supplementation of maize silage can be achieved in three ways:

TABLE 6 RECOMMENDED VARIETIES

Varieties"1"

*PS *S

Ρ G

G Ρ

0 Ρ G Ρ Ρ

G 0

Ρ G

0

Sprint Julia

Cistron LG 11

DeKalb 202 Campo

DeKalb 204 Kapio Anjou 210 Fronica Pioneer 131

Caldera 535 Anjou 196

Onyx 95 Orla 264

Austria 290 Mean

Origin

France Netherlands

Netherlands France

France Netherlands

France Germany France Netherlands Netherlands

Netherlands France

Netherlands Switzerland

Austria

OF

C] 9 0

FORAGE MAIZE

ass = very early ■ very late

9 9

8 8

7 7

6 6 6 6 6

5 5

4 4

3 -

(BASED ON DATA FROM TRIALS 1973 - 1975)

Dry matter at harvest (%)

28.4 28.4

27.1 26.6

26.4 26.3

25.4 25.3 24.7 24.7 24.7

24.4 24.2

23.2 23.0

23.4 -

Days to tasselling

83 83

87 90

87 88

90 89 87 89 89

89 86

90 90

92 -

Relative yield of dry matter

90 90

104 103

1O0 106

96 10O 10O 110 96

104 98

101 101

99 10O

(=11.6 t/ha)

Early vigour 9 = good 0 = poor

7 7

8 7

6 8

5 7 7 8 6

7 7

6 8

7 7

Resistance to lodging 9 = good 0 = poor

7 8

8 9

7 8

7 8 7 8 7

8 6

8 7

β 8

Height (cm)

175 174

186 182

188 189

179 188 186 185 177

190 191

188 193

204 186

+ Varieties classified for: General use G, Special use S, Provisional recommendation P, Becoming out-classed * Julia is recommended where a high dry matter content is especially important and Sprint is provisionally recommended for this purpose.

0.

210

a) addition of NPN at the time of ensiling b) addition of NPN at the time of feeding c) provision of a separate protein supplement, with or without NPN. There does not appear to be any difference in the efficiency

of protein usage by the animal between these three methods. A recent survey (ICI/MDA) showed that only 15% of crops had additives applied and most of these were applied after ensiling.

The advantage of adding NPN at the time of ensiling is that the maize becomes a complete feed and this simplifies the feeding system if only one type of ration is required. If the maize is to be given to different classes of stock with different protein requirements, then flexibility is lost. Either the protein in the maize is at the level required by the animals with the highest requirement for protein, in which case protein will be wasted by other classes of stock, or alternatively, the protein level is set at the requirement for the lowest level of protein and the silage has to be supplemented for those stock with more critical requirements and the advantage of a simple feeding system is lost.

A further point is that commercially available NPN products in Britain do not always provide the cheapest source of 'protein'. Prices per unit of protein vary markedly between different products and at different times (Table 2). The advice to beef producers is for them to check the relative prices before deciding on the method of supplementing the maize.

Cattle respond in rate of growth to the supplementation of maize silage with additional energy. Young cattle cannot eat sufficient maize silage to gain at satisfactory rates unless the silage is of very high dry matter content. It is at this stage that supplementary energy in the form of concentrates is partic­ularly worthwhile. A young calf of 150 kg live weight given maize silage and urea without any concentrates cannot be expected to gain at much more than 0.5 kg/d. The 'feeding of concentrates at 1 kg per head per day raises the performance to approximately 0.7 kg/d and increasing this level to 2 kg increases the perform­ance to approximately 0.9 kg/d.

The growth potential of the animal must be high in order to derive the maximum benefit from energy supplementation in the later stages of life, since excess energy is then reflected in

211 an increase in the fat content of carcass gain. Additional energy supplementation in the finishing stages is justified in some circumstances when it is necessary to increase the rate of finishing to meet trade requirements. This is particularly so with the late maturing breeds and crosses, such as Charoláis χ Friesian, and also with bulls.

In Britain, maize silage varies to a marked extent in dry matter content depending upon the season. Cattle fed on the wet material produced in 1974 had lower daily gains but these were still generally acceptable for the particular systems of pro­duction. Nevertheless, a high dry matter content is important because of the effect on intake, particularly with younger cattle. About 1 to 1^ kg of barley grain must be given with the lower dry matter silages to achieve the same performance as with the drier silages.

The performance of different types of cattle in different systems is shown in Table 7. Also shown for comparison are the results for feeding systems based on grass silage and hay. There was a consistent performance advantage to the maize silage units of nearly 0.1 kg/d. The slaughter weights and carcass characteristics of the maize silage cattle were typical of the production systems concerned.

TABLE 7 AVERAGE PERFORMANCE OF CATTLE ON MAIZE SILAGE

Overall daily gain (kg/d)

Friesian steers Hereford χ Friesian steers Large beef breed cross steers Other beef breed cross steers Beef cross heifers Slaughter ­ Live weight (kg)

­ Dead weight (kg)

Finishing suckled calves

Maize silage

0.8

­

­

0.9 0.8 0.7 417 229

Other feeds

0.7

­

­

0.8 0.7 0.6 414 228

Finishing store 'cattle

Maize silage

0.9

­

­

0.9 0.9 0.7 428 237

Other feeds

0.8

­

­

0.8 0.8 0.7 427 235

Finishing 13 month beef

Maize silage

0.9

0.9 0.9 ­

­

­

493 271

Other feeds

0.9

0.9 0.8 ­

­

­

480 264

212 Table 8 sets out the average rations for the three systems

of production.

TABLE 8 DETAILS OF MAIZE SILAGE DIETS

Feeds (kg/head/d)

Maize silage Cereals Protein concentrates Other feeds

Concentrate costs (p/d)* Concentrate costs (p/kg gain)*

Finishing suckled calves

21.8 0.7 1.4 3.1

Maize silage

13.4

17.3

Other feeding systems

23.8

32.7

Finishing store cattle

25.9 0.7 1.5 3.5

Maize silage

16.4

20.1

Other feeding systems

24.2

31.4

Finishing 18 month beef

22.7 0.6 1.6 3.9

Maize silage

17.1

19.9

Other feeding systems

24.7

32.1

Maize silage - concentrates at £75 per tonne, other feeding system concentrates at £70 per tonne.

In all cases maize silage resulted in a lower feed cost per kg of gain, mainly by saving concentrates (a 60% lower concentrate cost per kg of gain). The saving in feed costs is not the complete story since this does not take account of the difference in output per ha of maize silage compared to many other feeds (Table 4).

Maize silage can be fitted into a whole range of beef systems but the most exciting prospects are for the arable farm where maize silage is used as the main feed for an indoor system of beef production. The two most likely applications in Britain are a feedlot system starting with the reared dairy-bred calf and the winter finishing of suckled calves and stores.

213 FEEDLOT BEEF

Feedlot beef on the lines of the Italian and Bavarian units has applications in Britain. Production experience is limited but production targets are given in Table 9.

TABLE 9 PRODUCTION TARGETS FOR MAIZE SILAGE BEEF FROM FRIESIAN CALVES

Overall daily gain (kg) Slaughter age (days) Slaughter weight (kg) Protein concentrate (kg) Silage dry matter (t) Cattle per ha (at 9.7 t silage DM/ha)

Steers

0.95 420 445 460 1.65 5.9

Bulls

1.05 420 490 460 1.75 5.5

It is probable that to achieve the fat cover on the carcass demanded by the market and the standards required for fatstock certification, the diet for bulls may need supplement­ation with 150 kg of rolled barley during the final finishing period. Financially, such a system at spring 1976 prices pro­duces a gross margin of £100 per head and £490 per ha.

The equivalent gross margins per head and per ha for Friesian bulls sold at the same time from cereal beef units would be in the region of £48 and £130 respectively.

WINTER FINISHING SUCKLED CALVES AND STORES

One of the special attractions of maize silage for the winter finishing of suckled calves and stores is that'the quantity of maize silage available and its likely feeding value are known in advance of cattle purchases. This creates the opportunity for careful forward planning.

Production targets for Hereford crosses are shown in Table 10. Such a system would have produced a gross margin per head of about £65 compared with E30 per head for traditionally-fed cattle over the winter of 1975 to 1976.

214

TABLE 10 PRODUCTION TARGETS FOR WINTER FINISHING OF SUCKLED CALVES AND STORES ON MAIZE SILAGE

Live weight at purchase (kg) Feeding period (days) Slaughter weight (kg) Daily gain (kg) Protein concentrate (kg) Silage dry matter (t) Animals per ha (at 9.7 t silage DM)

Hereford cross steers Suckled calves

270 175 430 0.9 200 1.2 8.0

Store cattle

390 125 500 0.9 150 0.9 10.8

Animal Feed Science and Technology. 1 (1976) 215-226 215 Elsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands

DISCUSSION ON SESSION I

J.M. Wilkinson UK

It is obvious that there are very large effects of climate and of size of country on both the area of maize grown and the yield of maize per hectare. By comparison with the United States of America we have something like 8 million hectares currently grown in the countries represented at this conference. This compares with something just under 30 million hectares in the United States and a comparable area in Russia. We import nearly 20 million tons of maize each year and, of the countries here, only France is a significant exporter of maize grain. So this means that Western Europe is something like 50% self sufficient from what we can gather from projections of utilisation of maize by animals.

What I want you to do now, rather than discuss issues that will come up in later sessions, is to try to give some indication of how you see the situation developing in the future. For ex­ample , one or two speakers have made reference already to the yield of maize, in particular in the paper from Spain, and the paper from Portugal, the very large effect of irrigation. Yugo­slavia has a tremendous potential for maize production and it would be very interesting to hear how Dr. Sreckovic and his col­leagues see the area of maize developing in the future; for ex­ample, it may well be that Yugoslavia becomes a very large ex­porter of grain.

Where is that grain likely to go? Is it likely to come into Europe and replace American grain? Are we likely to see an increase in the proportion of maize grown for forage at the ex­pense of maize grown for grain or, as we heard from several countries, is the area of grain likely to stay about the same and the area of forage increase? Are we likely to see an im­provement, or an increase, in the proportion of maize silage in the diets of our beef cattle and, if so, will this release grain for feeding to pigs and to poultry?

I think these are the sort of things we should be consider­ing and I am wondering whether, for our host country, Dr. Sreckovic would like to say a few words about how he sees maize production

216 in the future. Would you like to do that to start or would you prefer to wait?

A. Sreckovic Yugoslavia

A little later.

J.M. Wilkinson

OK. Anybody wish to say a little about how they see the maize situation changing in the future?

J.S. da Costa Portugal

In my country I believe that we can improve the yield per hectare in the south because at the moment we are constructing some reservoirs which can help us to increase the production per hectare if we wish to produce more feed than before. It is my opinion that for the EEC the utilisation of maize silage would be best and that we should increase the output of grain in our country. This is what I assume will be the case for my country over the next four or five years.

J.M. Wilkinson

It is interesting that one of the very large producers in Europe is West Germany where, in contrast to France, a very large proportion of the maize area is now occupied by maize grown for silage. Yet, Germany imports a lot of maize for its large pop­ulation of non-ruminants. I wonder if they would like to comment on how things might develop in the future.

E. Zimmer West Germany

I can do it in a few words. We expect that maize for silage will be grown more in the north than it has been up to now because, as I said, two-thirds of the maize for silage is still in the south and this is going north. Maize for grain has already reached a peak and this is because of the limitations

217 of the available varieties. We don't think that we will increase our area of grain continuously in the future. Therefore, there is not a change of use from pigs to ruminants but it is a change in the rotations in the north and south of the country from grasses to maize, to have a higher yield potential. This is the problem in the northern part of Germany. In the southern parts we think we have a fairly stable situation. There is a com­pletely different question; we are not sure whether we have the right philosophy in breeding. I would raise this question to the auditorium. Normally we breed our maize for grain but we use it as a whole crop, or as we would a grass, for forage, and we are not sure whether this is the right philosophy of breeding - whether we have the right parameters or not, if we are intending to feed whole crop maize to ruminants.

Maybe we can get some answers from other countries.

J . Z s c h e i s c h l e r West Germany

Mr. Chairman, may I give some additional figures about the aspects of maize growing in Germany?

J.M. Wilkinson

Yes, in a very short time please.

J. Zscheischler

You see from the graph (Fig. la) that the area of maize for grain is going down. We had a peak, as Dr. Zimmer has told you, but in maize for silage the line goes straight upwards (Fig. lb). What we can expect in future years up to 1985 is that we could have, especially in Bavaria, up to 330 000 hectares. In Bavaria we have about 50% of the whole crop from Germany. I can say from our standpoint in Bavaria, maize for silage and also for green products, just to take this maize fresh, will be going on especially in the south of our country.

218

Gr<-iph 1 fl

1000 ha 110 r

90 -

70 -

50 -

30

DEVELOPMENT OF MAIZE PRODUCTION IN WEST GEKMANY 116 / S^li 1964-75

toe

I i 1 L 1964 66 68 70

Graph l b

1000ha 400

350

300

250

200

150

100

50

Φ 74 1975

DEVELOPMENT OF MAIZE SILAGE IN WEST GERMANY 1964-75 420

0U

381

I I I J I 1964 66 68 70 72 74 1975

F i g u r e 1 LfALB

219

J . L . Blanco Spain

I think one of the possibilities of maize will be to use the whole plant more efficiently. What I have presented in my paper is to have the whole crop, grain plus green plant, but with mature grain, i.e. 37 - 30% moisture in the grain, as the raw material for the paper industry that separates each com­ponent in relation to its chemical composition. For example, 40% can be for feeding beef cattle; 17% for paper production; 41% will be rich in the amino acids of the grain and will be for human or animal consumption. This is the hypothesis of our presentation this afternoon. We think that if this emphasis can be built up, incomes per hectare will be twice what we have today. With this doubling of the incomes of the farmer it will probably increase the area devoted to maize in the country.

J.M; Wilkinson

Are you aiming to increase the area or the yield by using more irrigation?

J.L. Blanco

Both. If we can give the farmer more money per hectare we can improve the system of cultivation and also it will increase production and an increase in production will increase the area of cultivation.

Refsgaard Andersen Denmark

We are especially looking at what goes on in Germany and this moving north. It was mentioned in the paper this morning from Denmark that we have a very small area at the moment but farmers are interested in this. The problem is really that which was mentioned by Ireland - the big difference in yield.

I would like to put a question to the Germans. Were the figures in Dr. Zimmer's paper, Table 2, for yield per hectare typical of the whole of Germany? In Denmark, as in Ireland, we have from 6 to 12 tons per hectare, this was mentioned by Mølle

220

this morning. On the next page of Zimmer's paper there is a table of Yield and Nutritive Value in Different Regions. You show that in the Netherlands there is a lower DM content of the maize crop than in other countries. Is that the correct picture of the factors for maize in different countries or what is the explanation because that is our problem in Denmark, this low dry matter content and the problem of getting enough DM intake. It has been mentioned in the Danish paper that we have our root crop where we can get 7 000 or 8 000 units SE/ha with the top or with a high amount of protein and also the grass he mentions, that could be in that area. So these two could compete in Den­mark and we look at those conditions before we make a decision.

E. Zimmer

Regarding your first question, this standard deviation of 7.3 was over the six year period and over all the regions of Germany. It is the published estimation of the yield from testing stations.

The second question - as you saw from the Table, I gave the authors and the year of their publication. Of course, this was the situation in the different countries in the different years, for example, the Netherlands' figures were published in 1971. I think Dr. Dijkstra took his samples in the previous years. I know from colleagues in the Netherlands that the situation was changing in the same way as it changed in the northern part of Germany, towards a higher and a more stable DM content over the years, so maybe now we are, in the northern parts, nearer 24% or 25% as an average over the years. I think this is the situation now in Northern Germany.

D. Oostendorp The fi ether lands

That is correct for the Netherlands. I think now the average would be around 25% - between 25% and 30% DM.

C. Lelong France

In France the grain maize acreage is at a ceiling and it is

221 quite unlikely to exceed 2 million ha of grain but only the yield can greatly increase now. For forage, if we have new varieties it is possible to increase the area mainly in the southern mountains below 500 to 700 metres. The area can surpass 1 million ha but probably will be very irregular because the climate of the last two or three years was very difficult for harvesting. We are developing wheat very quickly for beef feeding or cattle feeding in general.

J.M. Wilkinson

This is wheat as a forage crop?

C. Lelonq

Wheat as grain for animals, not for human consumption; also perhaps wheat as forage but for small farmers.

F. de Boer The Netherlands

I would like to refer to a remark made by Dr.. Zimmer and I think the remark was made by Dr. Kilkenny too, about the com­parison of maize silage output against grass output. Dr. Zimmer's remark was that in the northern part of his country maize silage was gaining in area because it had a higher output per ha than grass. This has been stated very frequently in our country too, but we have the impression that the comparison is not always correct, but sometimes false, because one is comparing the out­put of maize as silage and not when it has been passed through the cow so it is not really the net output. When you measure net output of maize silage per ha then grass output and maize output seem to be about equal. So the reasons, in our country, that maize silage is still gaining in area are a little differ­ent from just this false comparison of maize silage output and grass output.

R.J. Wilkins UK

There seems to be rather an odd feature here in thinking

222 about the spread of maize silage and of maize grain, particularly to areas further north in Europe, in that, as Dr. Zimmer men­tioned just now, most of the breeding effort in the maize crop, in Europe, is in relation to grain production and there is, cer­tainly in the more northern countries, tremendous stress in this programme to increasing earliness, making the maize crop more suitable to move further north ­ the maize crop for grain. How­

ever, in reviewing this situation we have not really identified any country in the north of Europe, and Γ don't think in the south of Europe, where we are projecting further increases in areas of grain maize although the breeding stress is in that direction. This seems to me to be very odd. Dr. Lelong has suggested that we have had in the last few years ­ two years perhaps ­ a case where the climate has been particularly hard for grain maize. I am wondering whether we, in this room, are being rather pessimistic in our view on the potential for in­creased grain maize production further north in Europe and that we are being influenced by a couple of years of not very good climate. Why, if the plant breeders are breeding the grain maize and breeding for earliness, are we saying in effect that they are not going to get their results?

R.K. Phipps UK

I think part of the answer to Wilkins' statement is that many plant breeders still consider that the best grain varieties are also the most useful ones for forage. I will not go any further than to say that at the present time but I think that answers part of the question raised by Dr. Wilkins.

J.C. Tayler UK

In comparing the yield of grass with maize I think we must not ignore the difference in fertiliser input. Very often com­parisons are made in terms of yield where maize is getting 150 kg of nitrogen per ha and grass will respond up to 300 or more kg of nitrogen per ha. I think in making this comparison we should be quite clear that there is a potential saving of the energy input as fertiliser with maize as compared with grass,

223

in situations where we are able to compare the two in similar sorts of climate.

W. Kaufmann West Germany

If we compare nitrogen fertiliser we have to consider the animal too, and there is a higher protein intake from grass which is wilted and on the other hand we should not only look at the energy/hectare but at the intake of other ruminants. Comparing maize silage with grass silages in the northern parts of Europe maize silage has too low a DM content and the intake is lower than the intake of very good grass silages.

J.B. Kilkenny UK

In Britain, when we are considering beef cattle as opposed to dairy cattle, we should be concentrating, not on the com­petitive elements of grass silage and maize silage, but on the fact that they are very complementary. The protein requirements of beef cattle are more than produced in grass silage but the intake and the growth of cattle is often disappointing. So we see grass silage and maize silage as being, in fact, complementary feeds suitable to be fed together.

J.M. Wilkinson

I wonder if our Belgian colleagues have any comments on the role of maize silage and its future development.

Ch. V. Boucqué Belgium

In Belgium there are still possibilities for increasing our area. Up to now it was beet which was replaced by maize silage. We had some 100 000 ha of fodder beet some ten years ago and now we have only 56 000 ha. With maize we have risen from zero up to about 80 000 ha. Why? The reason relates to the mechan­isation problems. Fodder beet still gives a bigger yield of DM and net energy than maize but the labour requirement is higher for the fodder beet compared with maize. In any case, with our

224 varieties we have some fodder beet. It's not the same in Den­mark where they have half sugar beet which can be mechanised very well. That is the reason why the area of fodder beet de­creased.

Concerning the intake mentioned by Dr. Kaufmann, v/e did a lot of experiments with dairy cattle on the intake of different roughages and even when the DM of the maize silage was about 24%, it varied between 24% and 30%, we always obtained the highest DM intake per kg of bodyweight compared with every kind of grass. Very good young calves were fed on the silage and they came up to the same level but maize silage was always among the greatest intake levels. Even in 1972, when DM was only 20%, we found 12 kg DM intake per covi-very, very high. In the comparison with grass that Dr. de Boer mentioned, I think that we should not compare the output with freshly eaten grass but when those forages are used for silage. Then we have also to take into ac­count the conservation losses with grass because they are larger than for maize.

F. de Boer

That's what I wanted to express but when we talk in Dutch we can make it much clearer probably! The reason is that when you have the net output of a hectare of grass and you compare it with the net output of energy from a hectare of maize, then the difference is not as much as is suggested many times when you read the literature or when you hear people talking about the comparison of maize and grass.

A. Sreckovic

For us in Yugoslavia it is very difficult for us to discuss this problem, comparing grass and maize, because we only produce maize. That is why the only possibility for us is to increase production by increasing the yield. That is why our main aim and official plan is to increase maize grain production within five years up to 12 million tons, reducing the total area by 300 000 ha, which means an increase of 25% in yield and a reduction of 13% of the area. That is a real possibility in our country.

225 Another possibility is to increase the total area under

maize for forage because we still do not produce enough of that form of maize.

Yet another possibility is that as suggested by Dr. Savie -to produce very soon some hybrids and varieties with a much higher protein content and even oil and especially lysine, in­creasing maize grain production and increasing protein production. That is our plan.

J.M. Wilkinson

Is the object to export this maize grain or to feed it to livestock?

A. Sreckovié

Yes, we export already. We export some commercial maize grain - 2 million tons - and we export a great deal of seed to different countries all over the world. We hope, of course, that this trade will increase in the future.

J.M. Wilkinson

Can I have a comment from Dr. Vetter on the likely change, if any, on the output of maize grain from the United States? We do depend very heavily, as we have seen from the papers al­ready, on imported grain from the United States. What are the trends?

R.L. V e t t e r United States of America

Concerning the comment on the effect of silage varieties versus grain varieties, the common consensus of opinion in the States is that we go for grain production in our silage because we are looking for energy in the silage also. In comparisons, we seldom see a good silage variety out-yielding in total energy per acre our grain varieties, but that's under harder conditions.

Secondly, the feeling is that we have probably reached near optimum yields considering our yields and area in production.

226

New land areas going in, unless under irrigation, will be much lower yielding, as we saw in these last two years particularly in Iowa where we were breaking up land. Parts of Iowa and Illinois could consider irrigation but do not have the water supply available without very high cost.

The general consensus is that irrigation would only be in much more restricted areas. So, I would think that we are near our production potentials unless we see an all-out effort made.

There is the strong possibility that we could see a shift in the areas of milo or grain sorghum production now which are under irrigation, we could see a shift to maize for grain pro­duction fairly easily. If the price goes high enough then I think we would see that shift taking place.

J.M. Wilkinson

We have come to the end of the time and it seems to be gen­erally accepted that an increase in either yield or the area or both, of maize, is desirable, and, in some countries, absolutely necessary in order to maintain desirable levels of livestock population and also to try and reduce dependence on imported supplies. There is the unresolved problem of suitability of varieties which we can possibly discuss again in the next ses­sion. There is also the unresolved question of the desirability of feeding ruminants on large quantities o£ maize grain, which no doubt we will also discuss in later sessions.

227

SESSION I I

THE EFFECT OF AGRONOMIC FACTORS ON THE YIELD AND COMPOSITION OF

THE MAIZE CROP, CONSIDERED IN RELATION TO THE METHOD OF USE OF

THE CROP

Choice of va r ie t y i n r e l a t i o n to s o i l , c l imate and e levat ions j s o i l c u l t i v a t i o n ; sowing methods and p lant populat ions! f e r t i l i s e r s and manure; con t ro l of weeds and pests¡ i r r i g a t i o n ; double cropping and crop ro ta t i ons .

Animal Feed Science and Technology, 1 (1976) 229-236 2 2 9 Elsevier Sdentine Publishing Company. Amsterdam - Printed in The Netherlands

THE USE OF TECHNIQUES OF MAIZE CULTIVATION TO MAXIMISE FEED FOR BEEF PRODUCTION

R. SAVIC Faculty of Agriculture, Novi Sad, Yugoslavia.

Maize and cattle production have many points in common. This is confirmed by the fact that the regions with a large-scale production of maize are also important cattle producers. In practice, the entire maize plant, minimally supplemented with other feeds and ingredients, is quite suitable for the nutrition of young as well as mature animals.

The following facts should be considered: a) Maize stalks gathered from 1 ha are sufficient feed

for one animal because this quantity, according to its starch value, equals 0.6 ha of hay or 0.3 ha of alfalfa.

b) Grain, cobs and stalks with leaves provide feed the value of which ranges between 8 000 and 12 000 starch units. The above figures are for the Danube valley, with normal agro-technical measures applied on unirrigated plots in a normal year.

c) Maize production, particularly grain production, can be relatively easily increased through breeding for new hybrids and the improvement of the present agro-technical measures.

d) Maize breeding develops cultivare suitable for mechanised production, with improved qualities of grain and stalks, i.e. with higher contents of sugar, oil, protein, lysine, amylopectin, etc.

If the above facts are taken into consideration, it can be concluded that maize is a rather valuable crop and that efforts to maximise the production of maize for cattle feed deserve our full attention. However, there are still open questions regarding the directions of work on both maize breeding and maize agro-techniques.

ECONOMY OF PRODUCTION AND UTILISATION OF MAIZE

The present-day maize hybrids have the ratio, grain:other plant parts, 1:0.8-1. The total dry matter ranges from

230

15 - 16 000 to 20 - 25 000 kg. The objective of maize production is to produce more

in a better, simpler and cheaper way. However, this problem is modified by the extent to which intensification depends on the maize producer and how much it depends on the supply of agricultural machinery, fertilisers, chemicals and fuel, on taxes and other costs which cannot be controlled by maize producers.

In terms of cattle feeding, the problems stem from the different ways in which maize can be used viz: 1. whole plant either fresh, dehydrated or ensiled; 2. ground, fresh or dried grain and cobs; 3. ground, fresh or dried grain; 4. ground dry cobs; 5. ensiled or dehydrated stalks without ears; or other combinations, depending on habits and technical capabilities of maize and cattle producers and on the purpose of cattle production.

However, changes in the methods of production and in the nutrition of cattle require a change in habits and new, and frequently high, investments in machinery and buildings.

Research into new techniques is undoubtedly necessary. However, progress is in most cases, a function of the economic effects of production since the economics of maize production are not directly correlated with yield - it is rather a correlation between finances expended and the prices achieved for the product.

In modern maize production (Gyorfi, 1975) 1 kcal of energy invested into production brings 2 kcal of grain (around 11:22 million kcal). The efficiency of utilisation of invested energy is obvious and rather high. However, there is a disproportion between the price of each kcal used and the price of each kcal produced, particularly if the fact is observed that about 20% of the total energy is used for drying, a further 25% is used by field machines and for transportation, while 45% is used for mineral fertilisation.

Beeson (1962) drew attention to the fact that 40% of the total digestible nutrients of the maize crop is contained in the cobs and stalks. He calculated that 1.5 acres (0.6 ha) would provide sufficient cob and stalle silage to maintain a beef cow producing one calf per year, and also drew attention

231

to the value of the fibre in cobs and stalks included in diets for cattle fattened in feedlots.

If, in cattle nutrition, the use of costly dried grain, which is frequently of decreased nutritional value, becomes prevalent over other plant parts, or these parts are entirely omitted, neither the best agro-technical measures nor the highest yielding hybrids can lead to profitable maize production, nor can the maize be regarded as the major component in nutrition for cattle production. There is a simple question - what type of production can be profitable if about 40% of usable products are thrown away?

TECHNOLOGY OF MAIZE PRODUCTION (GRAIN AND SILAGE)

Maize production in conditons without irrigation still largely depends on the climatic conditions of the year of growing. In all regions with average precipitation levels under 250-350 mm during the period of growth of maize, production is unstable and risky, particularly in the case of an irregular pattern of precipitation, in spite of sufficient reserves of winter moisture.

In such conditions, only an early planting of maize as the main crop is secure whereas second or additional plantings are largely uncertain.

This is why the producers who grow maize in unirrigated plots in arid or more favourable regions should strictly follow agro-technical recommendations in order to secure high and stable yields. These recommendations include the following items: ploughing time and depth, fertiliser type and quantity, planting time and density, weed and pest control.

Maize production in the Vojvodina plain can be used as an example. The plain, which has variable soils and a semi-arid climate, is the most important maize-producing region in Yugoslavia. In the period from 1948 - 1966, the mean yearly precipitation level was 601 mm, the mean yearly temperature 10.9°C. In the period from 1950 - 1970, the average precipitation level for the period of maize growth (April -

232

September) was 341 mm. In 1971, however, there were only 198 mm of rain; in 1975, on the other hand, 534 mm. It should be pointed out that in these two years there were considerable variations in precipitation in different parts of this relatively small region.

Ploughing time and depth: Two ploughings are usually performed. The first, shallow one, includes the ploughing in of the remains of the preceding crop, the second, a deeper basic one, follows. Basic ploughing for maize ranges from 30 - 35 cm. A depth of 25 cm is also satisfactory provided that ploughing for the preceding crop was deep.

The time of ploughing is an exceptionally important factor in the level and economics of maize production. According to Pavlovié et al. (1975), at the agro-industrial complex PIK "Tamia", Pancevo, in the period from 1971 - 1974, the grain yields of all maize hybrids examined decreased regularly and steadily with delay of the basic soil cultivation (Table 1). This finding applies to the entire maize production in Vojvodina, with understandable exceptions in certain months and years.

TABLE 1 EFFECT OF DATE OF CULTIVATION ON YIELD OF MAIZE GRAIN

Month of basic cultivation

July August September October November December January February March April May

Mean

Area (ha)

148.0 2 045.0 5 090.0 2 070.4 5 393.2 4 816.3 339.0 40.0 22.0 30.0 10.0

-

Grain yield (t/ha)

7.61 6.67 6.31 6.10 6.00 6.49 5.49 5.79 4.95 5.36 6.70

6.28

233

Fertiliser .type and quantity: The application of the most suitable quantity and kind of fertilisers is a regional question and it depends on the type of soil in the area planned for maize production and its content of minerals.

According to long-term examinations and the resulting experience (Drezgic and Markovic, 1975), it was concluded that on normally cultivated and fertilised soils, the production of about 10.0 t/ha of grain and 8.0 - 10.0 t/ha of air-dry stalks can be secured in Vojvodina with the application of 300 kg of pure nutrients in the ratio NPK = 1.0:0.8:0.6. The common procedure is to apply larger portions of phosphorus and potassium and a smaller portion of nitrogen before the basic cultivation. After that the nutrients in the ratio 1:1:1 are applied at the time of planting. Finally, one top dressing with pure nitrogen is performed at the stage of 7 - 9 leaves. There is a tendency to decrease the number of fertiliser applications to two, or even one, which would be performed before the basic cultivation.

Planting time and density: One of the important conditions for successful production is the earliest possible planting. Contemporary maize breeding is aimed at the development of genotypes suitable for particular agro-ecological conditions. In colder and usually humid regions of Europe, the seed should germinate and sprout in cold and moist soils and should bring, at the desired time, the highest possible grain yield or green forage and grain for silage.

In warmer and drier regions the seed should sprout in the soil which is frequently cold and dry but should be tolerant to high temperatures and drought in the course of vegetative growth.

As a relatively large number of hybrids with different lengths of growing period is presently used, it is necessary to learn as much as possible of their optimal planting density. The problems of optimal density and the maintenance of the desired number of plants per area unit until harvest are the final factors of grain and green forage yields.

In Vojvodina, for example, because of variability in its climate, it is recommended to plant 5 5 - 6 5 000 plants/ha for early hybrids (FAO 300 - 500) and 45 - 55 000 plants /ha for

234 late hybrids (FAO 600 - 800) for the production of grain and silage. Between 10 and 15% more viable seed should be planted in order to make up for possible but undefined losses in seed or plants which may occur during sprouting and growth. For the production of green forage, it is recommended that the figures given above should be increased by 20 - 25%. Equal planting density is recommended for the planting of maize as a first and a second crop.

The data for the period 1971 - 1974 gathered at the agro-industrial complex PIK "Sirmium", Sremska Mitrovica, by Stanisavljev et al. (1975), show the dependence of grain yields on the density at the time of harvest (Table 2).

TABLE 2 EFFECT OF PLANT DENSITY ON YIELD OF MAIZE GRAIN

Plants/ha

37 500 40 200 45 400 48 900 50 100

Mean

Area (ha)

3 901 11 013 14 146 4 632 2 036

-

Grain (t/ha)

4.66 5.81 7.03 7.92 9.03

6.62

Profitable maize production can be achieved through the planting of so-called full season maize. In view of climatic conditions it means that hybrids FAO 100 - 200 are full season maize in certain regions while hybrids FAO 700 - 800 are full season hybrids in others (Savie et al., 1975).

On the other hand, the complaint that late hybrids are a bad preceding crop because of late harvest, that the drying of grain with a high percentage of moisture is expensive, and that there is about 80% of water in the green parts of these hybrids transported for silage, can hardly be even partially justifiable in view of the present knowledge of cattle nutrition and the present technical possibilities.

235

Proper grain drying in a well organised maize harvest and transportation is carried out at a grain moisture of 35 - 40%, at which point the higher level of production makes up for the somewhat higher expense of drying.

When entire maize plants (grain, cobs, stalks) or only cobs and stalks are intended for silage, and stalks are cut 35 - 50 cm above the ground, the lower plant parts which contain the highest amounts of water (over 80%) and the lowest amounts of digestible constituents are left in the fields to be ploughed in.

In the production of concentrated silage (whole plant cut 35 - 50 cm above the ground) with 30 - 35% of dry matter at the time of ensiling (Palusek and Jerkan, 1975), nearly 50% of the total dry matter produced is in the form of grain (a yield of 7.2 t/ha). This means that pure grain has approximately the same nutritive value as 40 - 50 000 kg/ha of silage produced in densely planted plots with maize stalks cut to the ground, i.e. the silage made of reduced maize plants (the stalks cut 35-50 cm above the ground) with natural moisture contain about 38% more nutritive units than silage made in the normal way with higher planting density.

The possibility of using whole-crop maize for cattle nutrition means an increased utilisation of yields even if the present grain yields are not increased (Mutic, 1975).

CONCLUSION

Maize plants are abundant providers of quality cattle feed, i.e. they are first-rate feeds for both young and mature animals. In unirrigated plots, entire maize plants can yield between 8 000 and 12 000 or more starch units per ha.

In order to make the production of maize and cattle as economic and nutritious as possible, whole maize plants should be used for cattle nutrition in the form of concentrated silage because the production of dried or dehydrated grain is more expensive, while artificial drying may reduce grain quality.

In the production of silage from full season maize, the highest possible quality and cheaper yield of grain, cobs and stalks are obtained if the density is the same as for grain production and if maize stalks are cut 35 - 50 cm above the

236

ground. At the same time such production enables an easier and timely soil preparation for the following crop.

REFERENCES

Beeson,W.M­, 1962. Production and nutritional developments in beef cattle. Report at the National Beef Cattle Conference, Ames, Iowa, USA.

Drezgic, P. and Markovic, Z., 1975. Maize agro­techniques ­ present results and prospects of further development. Report at the Consultations on Maize in Vojvodina, November 1975, Duboka, "poljoprivrednik", Novi Sad, pp 29 ­ 34.

Györfi, Β., 1975. A kukorica korszerü agrotehnikája (manuscript) (Contemporary maize agro­techniques). Report at the Bajai Kukoricatermelisi Rendszer, Budapest.

Mutic, Ζ., 1975. Technology and technique of contemporary maize picking, preservation, and utilisation for cattle nutrition. Report at the Consultations on Maize in Vojvodina, November 1975, Duboka, "Poljoprivrednik", Novi Sad, pp 67 ­ 75.

Palusek, I. and Jerkan, Μ., 1975. Experiences in preparation and utilisation of concentrated silage for force­fed cattle nutrition. Report at the Consultations on Maize in Vojvodina, November 1975, Duboka, "Poljoprivrednik", Novi Sad, pp 77 ­ 80.

Pavlovic, I., Stojkovic, D. and Djordjevic, Μ., 1975. Characteristics of maize production at PIK "Tamis" in the period 1971 ­ 1974. Report at the Consultations on Maize in Vojvodina, November 1975, Duboka, "Poljoprivrednik", Novi Sad, pp 113 ­ 121.

Stanisavljevic, D., Petrov, P., Vasic, V., Zunkovic, P., Stepanovic, V. and Milosevic, M., 1975. Production of maize at PIK "Sirmium" and in co­operation. Report at the Consultations on Maize in Vojvodina, November 1975, Duboka, "Poljoprivrednik", Novi Sad, pp 123 ­ 137.

Savie, R., Vidojevic, Z., Saric, T., Jakovljevic, L., Gajic,M. and Sultan, Μ., 1975. The role and prospects of breeding in the improvement of maize production. Report at the Consultations on Maize in Vojvodina, November 1975, Duboka, "Poljoprivrednik", Novi Sad, pp 9 ­ 12.

Animat Feed Science and Technology. 1 (1976) 237-243 237 Elsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands

CULTIVATION OF MAIZE IN IRRIGATED AREAS FOR SILAGE AND GRAIN PRODUCTION AND THEIR USE BY RUMINANTS

A. MONTEAGUDO Department of Cereals,INIA, FINCA EL ENCIN, Box 127, Aleóla de Henares, Madrid. (Spain)

The increase in yields in recent years in Spain is due to diverse factors. Not only was the use of hybrids concerned in the maximum production of maize, but also irrigation and other cultural practices were involved. The importation of maize grain mainly for the feed industry, has also increased, ranging between 3.5 and 4.5 million tonnes. The total yield of grain on the other hand, remains at over 2 million tonnes per year.

At present, 60% of the total area used for grain production is irrigated. With an irrigated agriculture, the farmer can fertilise, plant and plan with confidence for a maximum prod­uction. The summary of yields in the trials on grain production during three years in every Spanish region indicates that it is possible to increase the level of production (Table 1). The regions with the greatest area of irrigation are Ebro, Andalucía and Extremadura, where the normal yield represents only 60% of the yields of the trials. Many problems are involved in incr­easing these yields; although we know a great deal about it, much remains to be learned.

Water is the most important factor in maize production. Irrigation allows man to control this factor of production to varying degrees. The yields are related to efficient irrigation. This irrigation efficiency might be defined as the relationship of the water retained in the root zone from irrigation to that delivered to the field. The water losses which occur are from evaporation (water surface), deep percolation and runoff from irrigation.

On sandy soils with high intake rates and low water holding capacities, most of the water loss is due to deep percolation. On clay soils, low intake rates, and runoff, are the major problems because the water must be kept in the furrows during a period of many hours, in order to get water to penetrate the soil.

238

TABLE 1 YIELDS IN t/ha OF THE TRIALS FOR GRAIN PRODUCTION DURING THREE YEARS IN COMPARISON WITH THE NORMAL YIELD IN SPAIN

Zone

Cantábrico Ebro Cataluña Duero Centro Levante Extremadura Andalucía

Mean

Annual mean

Yield (t/ha)

6.42 7.05 7.93 7.43 7.67 8.68 9.29 8.30

7.85

Number of trials

4 3 . 3 3 4 2 3 4

3.3

Maize irrigated

Area (000 ha)

21.1 81.8 31.9 17.9 18.5 21.2 49.6 51.0

36.6

Yield (t/ha)

4.00 5.71 6.58 4.15 5.61 4.88 4.00 5.07

5.09

TABLE 2 YIELDS OF MAIZE GRAIN (t/ha) WITH TWO PLANT DENSITIES AND THREE FREQUENCIES OF IRRIGATION

Number of applications of irrigation (a)

3 6 12

Mean LSD (0.05)=0.47

Density (b) plants/ha

30 000

4.58 5.56 6.65

5.60

60 000

4.86 7.00 8.60

6.82

Mean LSD (0.05)=0.84

4.72 6.28 7.62

6.21

CV (a) = 11.9% CV (b) = 10.5% Number of irrigations = HS Density = HS Interaction

Two densities at same number of irrigations LSD (0.05) = 0.82 Two 'number of irrigation' means at same density LSD (0.05) = 1.13

239 In order to obtain uniform water penetration on all parts of

a field, the field should have a uniform grade or slope. Land grading is required on most fields to get this uniformity of slope. This not only provides the slope desired but also prov­ides good surface drainage. Drainage is just as important for high production as irrigation. Efficient irrigation may allow 3 for the production of 100 kg of corn for 60 m of water, while inefficient irrigation may require 120 - 150 m of water to produce the same amount of corn. (Fischbach, 1959)

Water is removed from the soil by evaporation from the soil surface and by transpiration through the leaves of the plants. Most of the water that is used by transpiration through the leaves occurs from the rapid growth stage through the milk stage for maize. Optimum soil moisture within the root zone at.these stages is important for high yields. A good method of determining the available moisture in the soil is with the tensiometer. The tensiometer evaluates the water use, the moisture in any soil, and the penetration of water and the tensiometer tells when to irrigate and when to stop irrigating.

Robins and Domingo (1953) investigated the effect on corn yields of allowing plants to deplete the soil water to the perm­anent wilting point at certain stages of development. A soil water deficit maintained for one or two days during tasseling or silking reduced grain yields 22%, and soil water deficit for 6 - 8 days during this period reduced yields 50%. Denmead and Shaw (1960) also found that soil water stress at silking was more harmful to grain yield than stress at any other time.

The number of applications of irrigation during the different stages of development of maize has been found to affect yields (Table 2). With only three applications there was little yield difference between stands of 30 000 and 60 000 plants/ha. However, with a greater number of applications (6 or 12) plant density was of great importance and unless density was increased the benefit of this higher water supply was not sufficiently utilised. In other words, if it is dry, there is no advantage of higher population, but if moisture conditions are more favour­able (12 irrigations), one can expect considerable benefit from higher plant density.

240

TABLE 3 YIELDS OF MAIZE GRAIN, t/ha, WITH TWO PLANT DENSITIES AND FIVE TYPES OF PLANTING

Number of plants per hill (a)

1 1.5 2 3 4

Mean LSD (0.05) = 5.1

Density (b) plants/ha

30 000

8.41 7.80 8.51 8.26 7.94

8.18

60 000

9.67 8.55 9.70 9.54 10.16

9.52

Mean

9.04 8.18 9.11 8.90 9.00

8.85

Number of plants per hill = NS Density = HS Interaction = NS Two density means at same number of plants per hill: LSD (0.05) = 1.13

TABLE 4 YIELDS OF MAIZE GRAIN, t/ha, WITH TWO CLASSES OF MATURITY AND THREE PLANT DENSITIES

Class of maturity (FAO) (a)

400 800

Mean LSD (0.05) = 0.55

Density (b) plants/ha

30 000

6.47 9.00

7.73

60 000

9.27 9.96

9.61

90 000

7.95 9.70

8.82

Mean LSD (0.05) = 0.29

7.90 9.55

8.72

CV (a) = 3.9% CV (b) = 5.8% Hybrid maturity = HS Density Interaction = ΗΞ Two density means at same hybrid maturity LSD (O.05) = 0.82 Two classes of maturity at same density LSD (0.05) = 1.13

241 Yield increases with population until competitive effects

become important. Yield per plant then begins to decrease but yield per ha continues to increase until the competition is such that grain yield per ha 1-egins to decline. The optimum plant population level may vary markedly according to changes in agro-climatic conditions or in variety. In Spain, in the irrigated zone, the optimum plant density lies betweeen 40 000 and 80 000 plants per ha.

The desired plant population may be obtained with a large number of combinations of between-row spacings, within-row spacing and number of plants per hill. The trials made to find the influence of the check row did not give significant results (Table 3). In general, the highest yields are obtained with one or two plants per hill in all densities with a late hybrid (FAO 800) .

Early hybrids many times approach the yield of later matu­ring hybrids when planted at a heavier rate, but it has not been true for all early hybrids. The yields of two classes of matu­rity (early and late) at different densities were similar at 60 000 plants per ha but for early hybrids yield decreased at the lov; population and over all (Table 4). There was no assoc­iation between the average yielding ability of a hybrid and its response to increased plant population. The ability to give a larger response to increased population tended to be a variety characteristic to some extent. The interaction between maturity and population was highly significant in our trial.

The quality of grain is important, because the maize crop is primarily grown for food, feed and fodder. The percentage of protein in the grain is different in several single crosses, but we find a significant correlation (r=0.417**) between "class of grain" and protein content. The class of grain was measured with a classification of 1 to 5 for dent to flint. (Table 5). In the flint group, we can obtain hybrids with a percentage of protein near to 15%. The percentage of protein in the grain decreases with the yield and with the increase in plant population, but increases with the application of nitrogen. Actually with the use of the infra red analyser we can more easily increase the percentage of protein by breeding in new hybrids.

242

TABLE 5 PROTEIN AND LIPIDS FRACTION OF MAIZE GRAIN IN DIFFERENT SINGLE CROSSES IN RELATION TO TYPE OF GRAIN (% DM)

Class of grain Type

Dent Semiflint Flint

Total

Classification

1.5 - 2.5 3.0 - 3.5 4.0 - 5.0

1.5 - 5.0

Single crosses (No.)

21 17 34

72

Protein (%)

Mean

11.22 11.33 12.44

11.81

Deviation*

9.15-13.29 9.85-12.81 9.65-15.23

9.25-14.37

Lipid (%)

Mean

5.71 6.09 6.81

6.33

Deviation*

4.59-6.83 4.88-7.30 5.61-8.01

4.81-7.85

Correlation between class of grain: protein = 0.417** and lipids = 0.628** * Deviation values: (m - 25) to (m + 25)

TABLE 6 FORAGE PRODUCTION FROM CROPS OF DIFFERENT CLASSES OF MATURITY

Class of maturity (FAO)

600 700 800

Mean

Yields of forage (t/ha)

69.14 73.30 83.60

75.34

Yields of dry matter Total plant

(t/ha)

17.70 16.20 16.47

16.79

Ears (t/ha)

6.27 5.07 2.91

4.75

Dry matter (%) Total plant

25.6 22.1 19.7

22.5

Ears

29.1 24.4 18.5

24.0

Relation of ears/total plant (%) (dry matter)

35.42 31.30 17.67

28.13

TABLE 7 CHEMICAL COMPOSITION OF FORAGE OF DIFFERENT CLASSES OF MATURITY (% DM)

Class of maturity (FAO)

600 700 800

Mean

Dry matter

25.6 22.1 19.7

22.5

Protein

8.68 8.97 9.05

8.90

Lipid

2.36 2.09 1.68

2.04

Starch

62.16 60.96 57.16

60.09

Fibre

22.86 24.06 27.95

24.96

Ash

3.94 3.92 4.16

4.01

243

In Spain more than 100 000 ha are sown for maize silage which is normally consumed by ruminants, t'aize for silage can be harvested after silking but the dry matter yield, TDN and total protein yield are higher if the crop is harvested when the grain has reached the dough stage. The yield of forage is higher in the later hybrids (FAO 800), but the dry matter yields in the trials are the same in all the hybrids with different classes of maturity (Table 6). The proportion of ears in the total plant dry matter also decreased with later classes of maturity. The chemical composition of the forage indicates more dry matter in the earlier hybrids (FAO 600) but no greater content of protein (probably an effect of the characteristic of every hybrid) more ether extract and less crude fibre (Table 7). Maize has no competitor among the silages, not because it presents a better nutrient spectrum, but because of crop yield and the little attention required to make good silage. Under normal conditions, the maize will ordinarily yield more dry matter per unit of land than will the other silage crops.

REFERENCES

Denmead, O.T. and Shaw, R.T. 1960. Effect on corn yields of moisture stress at different stages of growth on the development and yield of corn. Agron. J. 52: 272-274.

Fischbach, P.E. 1959. Efficient use of irrigation water. Proceedings of fourteenth annual hybrid corn industry research conference: 85-93.

Robins, J.S. and Domingo, C.E. 1953. Some effects of severe soil moisture deficits at specific growth stages in corn. Agron. J. 45: 618-621.

Animal Feed Science ami Technology. 1 (19761 245-250 245 Llscvier Scientific Publishing Company. Amsterdam - Primed in The Netherlands

SELECTION OBJECTIVES FOR MAXIMUM YIELDS OF FEED WITH HYBRID MAIZE

J.L. BLANCO Departamento de Investigaciones Antropológicas y Genéticas de Barcelona, Consejo Superior de Investigaciones Cientificas, Zona Universitaria de Pedralbes, Barcelona 14, Spain.

To optimise feed production and cost, the research under way at the Department of "Investigaciones Antropológicas y Genéticas" points out the following objectives:

a) Inheritance and breeding for character directly related to photosynthetic capacity per plant, as a way to increase photosynthesis per hectare,

b) Breeding for high sugar content in the stalk at maturity, and essential amino acids of the grain,

c) Industrial processing of the total maize crop to reduce the cost of the feed for cattle, versus ensilage.

a) To increase photosynthesis per plant and per ha, we are studying the effect on the magnitude of the total surface of the plant leaves of the genetic complex that we call "decussate" because the plants with this character have opposite leaves (and opposite ears) and in two crossed directions, alternately along the stem. This genetic complex has other effects (some are defects and we are eliminating them by selection). Its effect on the total magnitude of the leaves per plant varies, depending on the interaction with the genetic background; in some stocks it increases the total surface of leaves per plant by only 50%, while in others this increase reaches 100% of that of the original normal stock.

The inheritance of this character is very complex; at least it is multifactorial, with some genes dominant and others recessives.

246

We are expecting through this character to increase the capacity of synthesis per plant for a better economy of its carbohydrates, to the benefit of the proportion of production of starch and sugars per unit of dry matter, per plant and per ha.

The last step of this part of research should be to compare the performance of normal hybrids and their corresponding "decussate" versions, in different degrees in plant populations, but there remains a great deal of work ahead in research and breeding.

b) At the 1956 FAO Maize Meeting for European and Mediterranean Countries, held in Cairo, we presented the first results of selection for high sugar in the stalk at grain maturity, (Blanco and Blanco, 1956). We have already developed several hybrids of different periods (from 300 to 800 FAO). The sugar in the stalk at maturity in these hybrids is around 31% of the dry matter. The amount of sugars per ha from these hybrids when cultivated in good conditions, under irrigation, in Spain, amounts to more that 3 500 kg/ha. Nevertheless, we think that better results can be achieved. Research and breeding should be intensified (Blanco et al., 1957) because the net energy of these sugars, as a feed for ruminants, is equivalent to 1/3 of the net energy of the grain and, in relation to the net energy of the whole plant of maize, (grain plus straw) it is an increase of 21%.

The use of these hybrids for silage has the advantage over the standard hybrids that they remain green, and the stalk contains plenty of juice, when the grain is matured: the dis­solved solids of the stalk juice range from 10% to 18% when the grain contains between 37% and 30% moisture.

When ensiling standard hybrids (at the doughy-hard stage) there is a sacrifice of 10% to 15% of the starch of the grain, but with high sugar hybrids the harvesting for ensiling can be delayed until full maturity and this loss is avoided.

We did not find any negative correlation between high sugar in the stalk at maturity and grain yield; on the contrary, there is evidence that selection for high sugar content in the stalk increases the capacity for total dry matter synthesis and adaptability (Blanco, 1972). In fact, the hybrid "España 22",

247

with high sugar in the stalk, achieved the greatest yield in all the trials we carried out in Spain during more than 10 years, in many factorial combinations, including different populations (ranging from 50 000 to 100 000 plants per ha). Top yields achieved were of 17 500 kg of dry grain per ha with a population of 75 000 plants per ha, under irrigation; and the highest green matter yield at maturity was 113 t/ha.

Research and selection for high lysine and trytophane looks very promising. Several researchers are finding inter­actions that compensate the losses in yield of the "Opaque 2" gene (Paez et al., 1969). We found such interactions too, and in some stocks we found interactions that triple the lysine (while the normal effect of "Opaque 2" is to double lysine in relation to the normal maize (Nelson, 1969)). We are intro­ducing the high lysine character into our high sugar hybrids. The relationship of this breeding programme with beef production depends firstly on the feeding value of high lysine maize to feed weaners and secondly to save the grain for monogastric animals and men and to feed cattle with the cheaper part of the plant. When ruminants are fed with maize grain we use feed suitable for monogastric animals. If maize grain is rich in lysine it should be saved for human nutrition.

Beef production should become cheaper if ruminants are fed only with the plants of maize while the grain is kept for more specialised uses. The question depends mainly on the limits for dry matter and fibre ingestion per ration, in relation to the needs for net energy, Total Digestible Nutrients and palatability for optimal economic production.

To discuss this we shall consider the standard limits and needs of the ration to feed calves of 272 kg and one year old, for beef production (Morrison, 1949):

Maximum dry matter, 8 kg. Minimum net energy, 9.7 Meal Minimum Total Digestible Nutrients (TDN), 4.9 kg. Then, the minimum energy per kg of DM is 1.21 Meal and

the minimum TDN per kg of DM is 0.61 kg. If we consider the composition of maize straw plus cob

(no sugar or grain) of standard hybrids, the concentration of the net energy is 0.78 Mcal/kg and 0.57 kg TDN/kg of dry matter.

248

For the high sugar hybrids we estimate that the net energy is 1.09 Meal and 0.72 kg TDN/kg of dry matter of the crop. To feed calves with the stover of the standard hybrids, and for the limit of 8 kg of dry matter in the ration, there would be a deficit of 7% TDN and 35% of net energy. With the plants rich in sugar in the stalk (but without grain) for the same limit of 8 kg of dry matter in the ration, there would be an excess of 18% of TDN and a deficit of net energy of 10%. On the basis of a yield of 8 000 kg/ha of maize grain, at 15% moisture, and considering the corresponding yield and compos­ition of plants/ha this means that to compensate for the deficit of energy, in the first case it is necessary to add to the straw and cobs of one ha, 4 564 kg of grain, but in the second case only 1 503 kg of grain is required. The difference is 3 061 kg of grain that can be saved per ha, or, for the 1 797 rations that can be supplied with the straw of one ha of standard hybrid it should be 3 433 kg of grain to obtain the same beef production with any one of both rations.

c) To make cheaper the feed for ruminants there is yet one other alternative.

The vascular bundles are around 60% of the weight of the stalk. These fibres are the component of the stalk which has the lowest feeding value but provides a good raw material for paper production. If this fibre were separated in the proportion of 55% of the dry matter of the stalk, the rest of the stalk, (sugar, pulp, etc.) plus the leaves, etc., would have per kg of dry matter, 0.73 kg TDN per kg (this has an excess of 19%), and the net energy is 1.23 Meal per kg, then, there will be no deficit in net energy and with such feed all the grain would be saved. For this calculation we give to the remaining part of the stalk (the pulp) 1.04 Mcal/kg and to the fibre the same value as to the straw of wheat, 0.22 Mcal/kg (Morrison, 1949). This needs to be investigated experimentally.

Stalk fibre for paper production has a price that is equal or superior to many fodders, although there are different values in different countries. Different combinations of the components of maize plants and grain can also be made to get different relations of net energy to dry matter and to add protein or non-protein nitrogen to the feed.

249

On the basis of a yield of 8 000 kg/ha of grain with the hybrid "Espana 22", we calculated a production of:

Feed for beef production of 1.23 Mcal/kg 7 795 kg = 40.8% Fibre for paper 3 355 kg = 17.5% Grain, rich in amino acids for men or for monogastric animals 8 000 kg = 41.7%

Total 19 150 kg = 100%

Several questions remain to be investigated for optimal industrialisation of hybrid maize rich in essential amino acids in the grain and sugar in the stalk at maturity, to optimise the cost of the ruminant product. For example:

a) Which is the optimum of fibre extraction in relation to actual and net energy production of this fibre, and in relation to the price of the cellulose for paper?

b) Different alternatives of harvesting, drying and processing the matured and green crop of maize with high sugar.

c) Cost of financing, operating, etc. of such processes. On the basis of Spanish prices we estimate that a cheap

feed for ruminants can be produced with such transformation and that the added values per ha of all the products equal the value of the grain per ha. Which part of this extra value will be consumed by the industrial process and which part will be saved in benefit of the price of feed for cattle? This question should be answered with experience of nutrition and of pilot industrial processing of the whole maize crop.

REFERENCES

Blanco, J.L. and Blanco, Μ., 1956. Maize hybrids with high sugar content in the stalk at grain maturity. Ninth FAO Hybrid Maize Meeting. Cairo, Egypt. October 1956. No. FAO/56/11/8537. p.10 Mimeo.

Blanco, M., Blanco, J.L. and Veiguinha, A.S. 1957. Obtención de híbridos de maiz de tallo azucarado, de doble aprovechamiento - grano y planta -y estudio comparativo, de su valor industrial, agricola y económico. Genet. Iber. 9:1-101.

250

Blanco, Μ., 1972 Estudio de la posibilidad de modificación en el contenido de azúcar y otros componentes del maiz para la mejora de su calidad. Tesis Doctoral. Universidad de Zaragoza.

Paez, Α.V., Helm, J.L., Zuber, M.S. 1969 Lysine content of "Opaque 2" maize kernels having different phenotypes. Crop Science, 9, 261 - 262.

Nelson, O.E. 1969- Genetic modification of protein quality in plants. Adv. Agron., 21, 171 - 194.

Morrison, F.B. 1949. Feeds and Feeding, Abridged VIII Ed. The Morrison Pub. Co., Ithaca, N.Y.

Animal Feed Science and Technology, 1(1976) 251-261 251 Elsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands

EFFECT OF AGRONOMIC FACTORS ON THE YIELD OF MAIZE AND ON ITS COMPOSITION IN RELATION TO ITS USE BY RUMINANTS

R.H. PHIPPS and R.F. VÎELLER National Institute for Research in Dairying, Reading, U.K.

ABSTRACT

The paper reviews work on how both air and soil temperatures can be modified by careful site selection and how this can, in the cooler northern regions of Europe, affect both yield and dry matter content of forage maize. Other important agronomic factors such as inorganic fertiliser, organic manure, plant density, genotype and date of harvest are discussed in relation to the quantity of forage produced. The effect of these factors on the development of plant components and their effect on chemically measured quality parameters are reviewed.

INTRODUCTION

In the cooler regions of Northern Europe there has been in recent years a rapid expansion in the area of forage maize (Bunting and Gunn, 1973). This revival of interest may be attributed to the advent of early maturing genotypes, selective herbicides and efficient harvesting machinery. The reasons for the farming community adopting forage maize are that it often outyields grass, has a high energy content and provides a valuable green feed during dry summers, its quality stays constant over a 5 to 6 week harvesting period and its reliabil­ity from year to year cannot be matched by other forage crops.

The present paper examines some of the agronomic factors affecting yield and discusses the effect of these on the quality of forage maize.

ENVIRONMENTAL FACTORS

Early maturing genotypes require approximately 660°C days to reach a dry matter content of 25% (Hough, 1975; Phipps et al., 1975). Hough (1975) stated that in order to exceed this

252 value in 9 out of 10 years in the UK a locality must receive on average 728°C days. These figures were used to define areas suitable for forage maize production: this area could be greatly increased by careful site selection, since well sheltered fields often receive a further 50°C days between May and October. Additional factors such as slope, aspect, cultivations and soil colour also influenced soil temperature and thus affected the rate of emergence, flowering date and final crop yields (Ludwig et al., 1957; Ludwig and Harper, 1958; Schmidt, 1973 and Phipps and Cockrane, 1975). The marked effect of site selection on final crop yields has been demonstrated clearly by Carr (1975). He noted that whole-crop dry matter yields increased from 9.5 t/ha on an exposed north facing chalk outcrop, to 16 t/ha on a well sheltered south facing brickearth. The crop at the well sheltered site also had a dry matter content 6% units higher than that on the exposed site. This would have allowed appreciably earlier harvesting of the crop, an important point in the cooler northern regions of Europe.

INORGANIC FERTILISER AND ORGANIC MANURE

In organic fertiliser Previous cropping, soil type, climate and organic manures

are all factors which affect the response to inorganic fertiliser.

In the USA and most of Europe, responses in forage maize dry matter yields have been recorded when up to 200 kg N/ha are applied (Kroth and Colyer, 1967; Doss et al·., 1970: Cummins, 1972; Allen et al., 1974; Maize Development Association, 1972, 1973, 1974) . The levels of phosphate and potash used were in few cases less than 100 kg/ha.

This situation differs markedly from that of the UK as only small increases in dry matter yield have been recorded when more than 80 kg N/ha have been used (Phipps and Pain, 1975; Pain et al., 1976). Responses to phosphate and potash have also been difficult to obtain. The smaller response obtained in the cooler northern maize growing areas may be due to their lower soil/root temperatures in the spring which could restrict nutrient uptake.

253 Organic manure

The escalating cost of inorganic fertiliser has resulted in renewed interest in the utilisation of organic manures. The application of 50­70 t/ha of slurry has produced crops of com­parable dry matter yield and dry matter content to those given inorganic fertiliser (Pain et al., 1976). However, high levels of slurry ( >105 t/ha) and inorganic nitrogen ( > 4 0 kg/ha) depressed yields mainly through the production of a less mature crop.

The use of slurry to grow forage maize not only doubled the energy output/input ratio but also reduced the problems of serious mineral imbalances and herbage rejection that occurred when it was applied to grassland (Pain and Phipps, 1975) . Table 1 shows that even very high rates of slurry had no marked effect on either digestibility or mineral composition of forage maize. TABLE 1 EFFECT OF SLURRY ON DIGESTIBILITY AND MINERAL COMPOSITION OF FORAGE MAIZE

% of DM Ν Ρ Κ Mg Ca Si02

Μη(ppm) Cu(ppm)

In vitro DÖMD

* Inorganic fertiliser

Control*

1.26 0.21 1.13 0.10 0.18 0.60 20.80 2.80 73

applied per ha

Level 125

1.22 0.20 1.90 0.08 0.26 1.30 25.00 2.20 68

134 kg N,

of slurry 250

1.34 0.22 1.45 0.07 0.21 1.30 35.OO 2.40 67

94 kg P205

(t/ha) 500

1.41 0.25 1.30 0.08 0.43 1.30 26.00 2.00 69

and 94 kg K20

PL/ANT DENSITY

In the UK the recommended plant density for forage maize is 10 to 15 plants/m^ and is based on the extensive work of Bunting (1971). This density ensures near maximum dry matter yields but ignores the fact that as density increases the proportion

254 of ear in the crop declines while that of the stem increases (Bunting and Willey, 1959; Rutger and Crowder, 1967; Thomson and Rogers, 1968; Cummins and Dobson, 1973; Allen et al., 1974 and Phipps, 1975). It also assumes no relationship between ear content and quality of the crop.

In the rest of Western Europe and the USA maximum dry matter yields are not achieved as plant density is restricted in order to obtain forage maize with a high proportion of ear (Bloc, 1971; Allen et al., 1974). This restriction in plant density and its subsequent sacrifice of dry matter yield has occurred because the quality of forage maize is often linked to ear and grain content. It is assumed that the best grain pro­ducing genotypes are also the most suitable for forage production (Chesneau, 1971; Demarquilly et al., 1971; Demarquilly, 1973). The outcome of this has been that most countries in Northern Europe assess genotypes solely on their grain producing ability, and that the UK is the exception in having a breeding programme for forage hybrids.

The link between forage quality and grain content is tenuous (Bunting and Gunn, 1973; Gunn, 1975) and may originate from Morrison (1956) who stated that the leaf, stem and ear had digestibility values of 61, 48, and 86% respectively. Thus it v/as thought that with the ear providing over 60% of the total digestible nutrients an increase in the proportion of ear and grain in the forage improved the feeding quality. These single component digestibility values do not take into account the translocation of nutrients from the stem to the ear. The same criticism can be levelled at trials comparing the quality of forages which had either been enhanced with additional ear material or had had the ear component removed (Andrieu and Demarquilly, 1974). Gunn (1975) in a recent review stated that "None of the experimental results provided convincing evidence to support the widely held belief that selection for high ear content will improve feeding quality". This sentiment is also shared by workers in Canada (Daynard and Hunter, 1975). The mineral content of maize is lov; but an increase in plant density from 4.9 to 16.7 plants/m2 had no practical effect on mineral content despite fairly large differences in grain component (Table 2).

255 TABLE 2 MINERAL CONTENT OF FORAGE MAIZE GROWN AT 4.9, 11.0 AND 16.7 PLANTS/m2

% in DM

Nitrogen Calcium Magnesium Phosphorus Potassium Sulphur mg/kg Zinc Manganese Copper Iron

4.9

1.31 0.24 0.13 0.20 1.80 0.11

25.00 26.30 3.90

114.30

Density (plants/m2) 11.0

1.26 0.23 0.14 0.18 1.67 0.11

33.30 24.20 3.70

112.30

16.7

1.25 0.23 0.14 0.17 1.72 0.11

23.50 22.30 3.60

110.80

Source: Phipps, 1975

Further work at the National Institute for Research in Dairying using a density-sensitive genotype (Anjou 210) planted at 5.0 and 15.0 plants/m^, produced forages of similar dry matter contents but containing 50 and 25% grain respectively (Phipps, 1976). Routine analyses showed the ΓΙΕ and DCP values of the high and lov; grain forages to be respectively 10.9 HJ/kg DM and 47g/kg DM and 10.6 MJ/kg DK'. and 56g/kg DM. These differences are small and it is conceivable that the levels of animal production achieved using these forages would also be similar. Although the energy values were similar, McAllan and Phipps (1976) showed that there were considerable differences in the carbohydrate components of the two crops (Table 3). These differences may be sufficiently large to produce . variation in animal performance.

The analyses in Table 3 show fundamental differences in the carbohydrate content of the crops which the DOMD values failed to indicate. Thus chemical analyses designed basically to measure the quality of grasses may have to be modified or altered when considering forage maize.

256 TABLE 3 WHOLE CROP CARBOHYDRATE CONTENT (g/kg DM). (PRELIMINARY RESULTS)

High grain Low grain

High grain Low grain

High grain Low grain

Sucrose 22.7 15.6

Mannose trace nil

Soluble sugars Fructose Glucose Mannose 18.1 22.0

Galactose 10.9 14.4

Starch 311.4 228.9

27.0 0.6 27.7 0.3

Hemicelluloses Arabinose

29.1 35.9

Total

Galactose 0.8 nil

Xylose 118.9 137.2

carbohydrates 689.5 631.7

Total 69.2 65.3

Total 158.9 187.5

GENOTYPE AND DATE OF HARVEST

In thé UK and France a large number of genotypes with different maturity ratings have been studied at various stages of development (Harris, 1965; Demarquilly et al., 1971). Analyses showed that the in vitro DOMD value of the whole crop was not markedly altered by either harvest date or genotype (Table 4 ) . TABLE 4 EFFECT OF HARVEST DATE AND GENOTYPE ON THE QUALITY OF FORAGE MAIZE

Caldera 20 18 21

LG 11 20 18 21

535 Aug Sept Oct

Aug Sept Oct

Whole crop % DOMD 72.1 72.4 71.1

72.8 70.4 69.2

% Ear 19 46 55

27 52 62

DM % 16 20 24

17 24 29

Source: Phipps, 1975

257

The constant whole crop DOf'-D value occurred because the dry matter yield and DOMD value of the leaf and stem declined, while the yield of ear increased and its D0I1D value remained constant (Tables 4 and 5). TABLE 5 QUALITY OF PLANT COMPONENTS

Caldera 535 20 Aug 18 Sept 21 Oct

DOMD (%) Leaf

65.6 63.6 60.7

Sten

' 71.3 67.8 61.2

Ear

82.3 79.1 79.4

Whole crop

72.1 72.4 71.1

Source: Phipps, 1975

The fall in DOMD value of the leaf and stem indicated that a substantial quantity of carbohydrates was translocated to the ear.

Wilkinson and Osbourn (1975) drew attention to the effect of dry matter content on silage fermentation characteristics. They considered that it was an important quality parameter, but pointed out that in the cooler northern regions of Europe it was difficult to achieve dry matter contents in excess of 25% at the end of the growing season. Kith dry matter contents below 25%, nutrients could be lost, effluent and the resultant danger of pollution could occur and intakes would be depressed (Fisher et al., 1968; Vérité et al., 1971). If, however, harvest date is delayed in order to obtain a higher dry matter content harvesting problems will be encountered and problems over future cropping patterns will be created. Thus, growers in these cooler northern regions must have early maturing genotypes with both high dry matter yields and high dry matter contents. Wilkinson and Osbourn (1975) considered the best way of achieving these objectives was to produce early maturing genotypes with a high ear content (starch) as there was a positive relationship between starch and dry matter content.

Comparisons between isogenic sterile and fertile plants

258 (Marten and Westerberg, 1972) , at densities commonly used for silage in northern Europe, showed little difference in dry matter yield, dry matter content, crude protein or in vitro DOKD. This led Bunting (1975) to state that "The importance attached to high grain content as an essential requirement for yield and quality in forage maize is exaggerated".

Gunn (1975) reviewed the literature on early and late maturing genotypes, normal and dwarf genotypes, tillered and non-tillered genotypes, and found no conclusive evidence to suggest that maximising the ear to stover ratio would enhance markedly the nutritive value of forage maize. However, a marked improvement in quality has been noted when the brown mid-rib mutant gene was incorporated in forage hybrids.

CONCLUSIONS

In the cooler northern regions dry matter yield and dry matter content can be increased greatly by careful site selection. In certain areas dry matter yield is sacrificed in order to produce forage with a high ear content. However, chemical analyses have not provided convincing evidence that a high ear content is mandatory for good quality forage. The effect of ear content must also be considered in relation to the effect of plant components on silage fermentation character­istics, volatile fatty acid production in the rumen and finally, but most important of all, on animal performance. These studies must be carried out with materials of similar dry matter content and must permit the normal movement of nutrients within the entire plant. The answer will have a profound effect on breeding programmes.

If the grain content is vital in producing good quality forage then genotypes which are not sensitive to density will be produced, thus coupling high dry matter yield and high grain content. However, if the grain content is not a vital component plant breeders would be able to use a much wider range of genetic material in the production of new forage maize genotypes.

259

REFERENCES

Allen, M., Ellzey, H.D., Nelson, B.D. and Montgomery, CR. 1974. Effect of nitrogen, population and hybrid on the yield and quality of irrigated corn for silage on Providence soil. Louisiana Agricultural Experimental Station, Bulletin No.676.

Andrieu, J. and Demarquilly, C. 1974. Chemical composition, digestibility and voluntary intake of fresh and ensiled male sterile maize. Annales de Zootechnie. 23, 1-25.

Bloc, D. 1971. La production du mais fourrage. Bulletin Technique d'Information No.264, 979-986.

Bunting, E.S. 1971. Plant density and yield of shoot dry material in maize in England. Journal of Agricultural Science, Cambridge, 77, 175-185.

Bunting, E.S. 1976. The question of grain content and forage quality in maize: comparisons between isogenic fertile and sterile plants. Journal of Agricultural Science, Cambridge, 85, 455-463.

Bunting, E.S. and Willey, L.A. 1959. The cultivation of maize for fodder and ensilage. 2. The effect of changes in plant density. Journal of Agricultural Science, Cambridge, 52, 313-319.

Bunting, E.S. and Gunn, R.E. 1973. Maize in Britain - a survey of research and breeding. Plant Breeding Institute. Annual Report.

Carr, M.K.U. 1975. The 1974 maize season in perspective. Maize Development Association Bulletin No.73.

Chesneau, J.C. 1971. Pour bien réussir la culture du mais-ensilage. Cultivar, No. 28, 1-5.

Cummins, D.G. 1972. Yield and quality of corn for silage grown under different fertiliser regimes. Georgia Agricultural Experimental Station, Bulletin No.105.

Cummins, D.G. and McCullough, M.E. 1971. Comparison of male sterile and male fertile corn for silage. Journal of Agronomy, 63, 46-47.

Cummins, D.G. and Dobson, J.W. 1973. Corn for silage as influenced by hybrid maturity, row spacing, plant population and climate. Journal of Agronomy, 65_, 240-243.

Daynard, T.B. and Hunter, R.B. 1975. Relationships among whole-plant moisture, grain moisture, dry matter yield and quality of whole plant corn silage. Canadian Journal of Plant Science, 55, 77-84

Demarquilly, C. 1973. Composition chimique, valeur nutritive et ingestibilité pour le ruminant des différentes formes de mais. L'Elevage, Numero hors série Le Mais 146-147

260

Demarquilly, C , Haurez, P., Journet, M., Lelong, C. and Malterre, C. 1971. Le ma'í.s plante entière: composition, valeur alimentaire, utilisation par les bovins. Bulletins Technique d'Information 264, 1OO1-1O10.

Doss, B.D., King, A. and Patterson, R.M. 1970. Yield components and water use by silage corn with irrigation, plastic mulch, nitrogen fertilisation and plant spacing. Journal of Agronomy, 62, 541-544.

Fisher, L.J., Logan, V.A., Donovan, L.S. and Carson, R.B. 1968, Factors influencing dry matter intake and utilisation of corn silage by lactating cows. Canadian Journal of Animal Science, 48, 207-214

Gunn, R.E. 1975. Breeding maize for forage production. Proceedings 8th Congress of Eucarpia, Versailles, 1975.

Hough, M.N. 1975 Mapping areas of Britain suitable for maize on the basis of temperature. Agricultural Development and Advisory Service, Quarterly Review, 18, 64-72.

Kroth, E.M. and Colyer, D. 1967 Response of corn to nitrogen fertilisation and plant population. Missouri Agricultural Experimental Station, Special Report 76.

Ludwig, J.W., Bunting, E.S. and Harper, J.L. 1957 The influence of environment on seed and seedling mortality. 3. The influence of aspect on maize germination. Journal of Ecology, 45, 205-224.

Ludwig, J.W. and Harper, J.L. 1958. The influence of environment on seed and seedling mortality. 8. The influence of soil colour. Journal of Ecology, 46, 381-389.

Maize Development Association 1972. Bulletin No. 46 Maize Development Association 1973. Bulletin No. 51 Maize Development Association 1974. Bulletin No. 69 Morrison, F.B. 1956 Feeds and Feeding. New York: Ithaca. McAllan, A.B. and Phipps, R.H. 1976 Unpublished data. Pain, B.F. and Phipps R.H. 1974 The effect of heavy dressings of slurry

on forage maize. Journal of the British Grassland Society, 29, 263-267.

Pain, B.F. and Phipps, R.H. 1974. The energy to grow maize. New Scientist, 66_, 394-396.

Pain, B.F., Phipps, R.H. and Richardson, S.J. 1976 The effects of inorganic nitrogen fertiliser and cattle slurry on forage maize. In press.

Phipps, R.H. 1976. Unpublished data.

261

Phipps, R.H. 1975. A note on the effect of genotype, density and row width on the yield and quality of forage maize. Journal of Agricultural Science, Cambridge, 85, 567-569.

Phipps, R.H., Fulford, Rosemary J. and Crofts, F.C. 1975. Relationships between the production of forage maize and accumulated temperature. Ontario Heat Units and solar radiation.. Agricultural Meteorology, 14, 385-397.

Phipps, R.H. and Cockrane, J. 1975. The production of forage maize and the effect of bitumen mulch on soil temperature. Agricultural Meteorology, 14_, 399-404.

Phipps, R.H. and Pain, B.F. 1975. Levels of fertiliser for forage maize. Agricultural Development and Advisory Service, Quarterly Review, 1£, 49-54.

Rutger, J.N. and Crowder, L.V. 1967. Effect of high plant density on silage and grain yields of six corn hybrids. Crop Science, T_, 182-184.

Schmidt, 0. (1973) The effect of bitumen emulsions on soil temperature and plant yield. Herbage Abstracts, 44_, 1539.

Thomson, A.J. and Rogers, H.H. 1968. Yield and quality components in maize grown for silage. Journal of Agricultural Science, Cambridge, 71, 393-403.

M

Vérité, R., Hoden, A. and Journet, M. 1971. Avec un bon ensilage de mais les vaches laitières consomment moins d'aliment concentré. L'Elevage, numero hors série Le Mais, 157-163.

Wilkinson, J.M. and Osbourn, D.F. 1975. Objectives in breeding forage maize for improved nutritive value. Proceedings 8th Congress of Eucarpia, Versailles, 1975.

Animal Feed Science and Technology. 1 (1976) 263-271 263

Elsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands

AGRONOMIC FACTORS AFFECTING THE GROWTH AND COMPOSITION OF THE MAIZE PLANT

J. ANDRIEU

Institut National de la Recherche Agronomique, Centre de Recherches Zootechniques et Vétérinaires, Theix, 63110 Beaumont, France.

INTRODUCTION

As French results during the last five years have shown very clearly, the dry matter yield of forage maize and the composition of the plant at harvest can be very variable. In France, early varieties, bred for grain yield and often with a common ancestor, INRA 258, are generally used for forage maize production. In these conditions, it could be suggested that the great variability in the results obtained was due more to environmental conditions than to the varieties used. In the light of results both in the bibliography and those obtained in France by the Institut National de la Recherche Agronomique (INRA), by the Institut Technique des Céréales et des Fourrages (ITCF) and by the Association Générale des Producteurs de Mais (AGPM), we shall examine the importance of different environmental factors on plant productivity and composition. Since the subject is very wide, we shall consider only early and very early varieties (FAO index below 300) during the stage of growth when they can be ensiled, that is from the late milk stage (about 25% of. dry matter in the plant) to the early glaze stage (about 35% dry matter).

INFLUENCE OF AGRONOMIC TECHNIQUES

Plant density From many trials in different parts of the world (Crossman,

1968; Eddowes, 1969; Rutger and Crowder, 1967), it appears that the dry matter production of the whole plant increases up to a certain density and levels off. Maximum production is attained at varying densities, but generally increases with favourable conditions and early date of harvest (when the effects of lodging and of competition between plants are less noticeable).

TABLE 1 EFFECT OF PLANT DENSITY ON DRY MATTER YIELDS OF FORAGE MAIZE (ITCF and AGPM trials)

YEAR

REGION

Earliness group

Plant density (thousands/ha )

Number of trials

Dry matter content (%)

Dry matter yield (t/ha)

Ears in total dry matter (%)*

1970 to 1972

West - East -North - Centre

Groups 0 and 1

85.7 100.4

50

30.2

14.5

-

29.8

15.1

-

Centre

Beginning of Group 1

74.1 88.2

14

35o6

14.4

-

35.2

14.7

-

1 9 7 4

All regions

Group 1

74.1 93.4 113.5 130.1.

12

27.4

11.0

55.0

26.3

11.8

50.5

26.3

12.4

49.5

25.6

12.1

46.0

1 9 7 5

Cantal - Cote du Nord - Vendée

Beginning of Group 1

74.2 89.8 112.5 125,2

16

31.7

12.5

64.5

30.5

12.8

62.5

29.7

13.3

59.0

29.1

13.6

57.5

"ears" - grain, rachis, husks and ear shank.

265 In addition, it is generally considered that a maize destined for silage can be sown more densely than grain maize.

Trials carried out by the Technical Institutes (ITCF and AGPM; Table 1) indicate that the optimum density for the harvest of plants containing about 30% dry matter (late dough, early glaze, stage) is 15 ­ 20% greater than that considered optimum for grain production. In French conditions densities of 90 000 ­ 110 000 plants/ha are recommended for very early varieties and 75 000 ­ 90 000 plants/ha for early varieties. Increase in density results in an average increase of 0.5 t of DM/ha (range, from O ­ 1.5 t) and in a slight reduction in percentage of ear (with its husks) in the dry matter (2.5 percentage units on average). Similarly, trials carried out in our laboratory (Andrieu and Demarquilly, 1974) show (Table 2) that the reductions in ash, crude fibre and more especially in crude protein content associated with increasing plant density are small. » Fertilisers

The influence of level of fertiliser on the production of forage maize has not been the object of any systematic studies in France. Most often fertiliser rates are comparable with those advised for grain maize: 150 units of Ρ,Ο­ and K_0 and 100 ­ 150 units of N/ha depending on whether or not manure is provided.

As Harshbarger et al. (1954) showed, nitrogen fertilisation does not alter the morphological composition of the plant (notably the percentage of ear in the whole plant dry matter) at least, under good environmental conditions. In contrast, it generally increases the crude protein content of the plant, although to a variable extent ( 7 ­ 86%) (Alexander et al. , 1963; Jahn, 1961; Nandpuri, 1964). Essentially, this increase results from an increase in the crude protein content of stems and leaves (Genter,1960). In our trials (Andrieu and Demarquilly, 1974), the crude protein content of maize which has received 100 ­ 150 units N/ha, varies from 7.5 ­ 10.0% of the dry matter but can fall to 5% in the case of maize suffering from excess soil moisture at emergence and thereafter from a considerable summer drought (Table 2).

TABLE 2 INFLUENCE OF PLANT DENSITY ON FORAGE MAIZE COMPOSITION

YEAR

Place

Plant density (thousands/ha)

Number of comparisons

Harvest date (1)

DM content (%)

COMPOSITION (% DM)

Ash

Crude protein

Crude fibre

1 9 7 0

MONTOLDRE (2) (4)

62.2

3

58 + 3

29.3 + 1.1

5.2 + 0.3

5.5 + 0.7

22.0 + 1.4

79.9

3

57 + 5

27.6 + 1.0

6.0 + o;3

5.4 + 0.3

21.7 + 1.2

MALINTRAT (2)

74.5

3

4 1 + 3

32.1 + 1.6

5.8 + 0.4

9.7 + 0.2

17.7 + 1.6

93.7

3

43 + 2

31.4 + 2.2

6.3 + 0.6

9.3 + 0.2

19.6 + 1.4

1 9 7 3

CHANONAT (3)

86.6

8

44 + 4

36.8 + 4.0

5.6 + 0.3

3.0 + 0.5

21.0 + 0.8

109.6

8

4 5 + 4

36.9 + 4.2

5.9 + 0.3

8.0 + 0.6

22.5 + 1.8

(1) Harvest date expressed as days after female flowering; (2) Composition of silage; (3) Composition at ensiling; (4) Drought-stricken maize.

267 Sowing date

It is well known that the influence of date of sowing on the production and composition of forage maize can be very variable, depending on the earliness of the variety and environ­mental conditions. It also depends considerably on the date of harvest when the environment is favourable (Table 3, 1st and 2nd sowing dates). In regions of France where only early or very early varieties will reach 30% dry matter (north and west of France), the trials carried out by AGPM (1972 - 75) show that for a given harvest date (imposed by climatic conditions at the end of the growing season), later sowing gives poorer results than earlier sowing, both in terms of dry matter production and percentage of ear in the plant. With later sowing, temperatures are too low during the phase of grain maturation and limit grain development (Table 3, 3rd sowing date). Thus sowing as early as possible, about 15th April, is advised.

In regions where late varieties reach 30% dry matter (south west of France, for example), the influence of sowing date has been little studied with early varieties, although these may provide a useful catch crop. According to work by Kiesselbach (1950) and Van Dobben (1962) later sowing would give taller plants with a reduced percentage of ear, possibly owing to longer day length and higher daily temperatures during the first few weeks after emergence.

INFLUENCE OF CLIMATIC FACTORS

As the results we have obtained with INRA 258 'indicate (Table 4), climatic conditions are by far the most important factors affecting forage maize production and composition. In good growing conditions early varieties harvested at a satis­factory dry matter content of 30 - 35% (early glaze stage) give production levels of 12 - 14 t/ha of dry matter of which 60 -65% is in the ear and husk.

In contrast, the trials we carried out in 1970 at Montoldre (Table 4) illustrate the very unfavourable effect of drought during flowering in maize crops grown on a poorly drained clay soil. Similarly, many authors have shown the great importance of temperature during and after flowering on grain development

TABLE 3 EFFECT OF DATE OF SOWING ON COMPOSITION AND YIELD OF FORAGE MAIZE (Trial carried out by AGPM at Boigneville - 1972Ί' - Average of three varieties)

Date of sowing

Date of harvest

15 Sept 26 Sept 5 Oct 17 Oct 27 Oct 8 Nov

Dry matter content (%)

25 April

23.9 27.4 31.0 35.6 36.8 41.5

19 May

20.3 22.8 25.7 30.7 34.2 36.0

12 June

15.6 17.7 19.6 22.6 23.9 23.4

Dry matter yields (t/ha)

25 April

13.4 13.9 15.5 14.8 14.5 14.2

19 May

12.2 13.3 13.7 14.8 14.2 13.9

12 June

9.4 10.5 12.2 13.3 12.9 11.3

Contribution of ear in total dry matter

(%)

25 April

55.9 58.4 60.6 62.4 63.4 67.3

19 May

47.8 54.0 56.6 60.6 62.7 65.2

12 June

28.9 36.9 43.5 48.1 48.9 52.2

(1) The seasons during which this experiment was in progress were highly favourable.

TABLE 4 EFFECT OF YEAR AND CLIMATIC FACTORS ON THE COMPOSITION AND YIELD OF VARIETY INRA 258 (2)

Year

1968 1969 1969 1970 1970 1972 1972

1973

Seasons

Favourable Favourable Favourable Drought at flowering Favourable Low temperature Low temperature and frost (1) Drought at dough stage

Plant density (thousands /ha)

71 50 65 75 70 104

104 84

Dates of

sowing

19 April 15 May 13 May 4 May 5 May

22 May

22 May 22 May

Days after flower­ing (3)

65 61 54 42 59 66

85 49

Composition of forage at ensiling

Ears (% of DM)

65.0 68.5 66.6 56.3 61.0 48.0

52.9 62.5

Dry matter content (%)

33.0 33.7 30.8 29.9 33.9 21.2

23.6 41.8

Ash (% of DM)

4.7 4.1 5.0 6.3 5.7 6.1

6.2 5.7

Crude protein (% of DM)

6.3 7.6 6.8 5.3

10.1 10.2

9.1 7.6

Crude fibre (% of DM)

17.3 17.8 17.7 19.6 18.5 20.5

21.5 21.0

Starch (% of DM)

26.6 30.0 28.9 15.3 22.5 5.9

12.0 23.5

Yields (t/ha)

-9.9 10.7 6.0 14.2 9.8

10.5 10.8

(1) Leaves were burnt by frost between two harvest dates. (2) All these trials have been carried out in the Massif-Central n.ear Clermont-Ferrand. (3) Harvest date expressed as days after female flowering.

270 and thus on the increase of dry matter content in the ear and in the whole plant. Two years of trials with the variety INRA 260 by Bloc and Gouet (1973) have shown that a close cor­relation exists between the sum of the average daily temperature after flowering (X, base 7 C) and the dry matter content of the ear (Y ) and of the plant (Y ):

Υχ = 0.26 + 0.073 X ; r = 0.96 Y2 = 4.88 + 0.045 X ; r = 0.95

According to these results, about 560°C (calculated with a base of 7°C) after the point of female flowering (silking) is necessary for development to 30% dry matter in the plant. In Northern France where accumulated temperatures rarely reach 450°C, the very early varieties, although harvested long after flowering, give only 8 ­ 10 t DM/ha since their grain is not developed. Their case is well illustrated by the trial we carried out in 1972, a particularly cold year in the Massif­Central (Table 4).

CONCLUSION

During recent years the area under forage maize cultivation in France and in Europe as a whole, has increased spectacularly. The principal reasons for this extension are the following:

a) the maize crop can be completely mechanised and with the use of hybrid varieties, is capable of giving high yields, b) there are numerous possibilities for using maize in animal feeds, particularly for ruminants. The variation in potential utilisation method is much appreciated by farmers. However, results obtained during the last five years show

that yield amd plant composition can be very variable, particul­arly in relation to climatic conditions. This is in part due to an extension of the crop on to hill land and in to more northern zones. Knowledge of accumulated temperatures, of the frequency of early frost and of the incidence of drought appear necessary prerequisites to the introduction of the crop into a given region· This is especially important since, as we shall show in another publication (Andrieu, 1976), the nutritive value of silage may be low in unfavourable climatic conditions.

271

REFERENCES

Alexander, R.A., Hentges, J.F., Robertson, W.K., Barden, G.A., Mc Call, J.T. 1963 Composition and digestibility of corn as affected by fertilizer

rate and plant population. J. Anim. Sci., 22, 5-8. Andrieu J. and Demarquilly, C., 1974 Valeur alimentaire du mais-fourrage

11 - Influence du stade de végétation, de la variété, du peuplement, de l'enrichissement en épis et de l'addition d'urée sur la digestibilité et l'ingestibilité de l'ensilage de maïs. Ann. Zootech., 23, 1 - 25.

Bloc, D. and Gouet, J.P. 1973 Influence des sommes de température sur la maturité du maïs. Docum. ITCF - AGPM.

Crossman, G. 1968 Plant density and dry matter production in maize. Field Crop Abstr., 21, p. 116.

Eddowes, M. 1969 Physiological studies of competition in zea mays 1, 11, 111. J. agrie. Sci-, Camb., 72, 185 - 215.

Genter, C.F. 1960 Corn and other crops for silage in Virginia. Virginia Agr. Expt. Sta., Bull. 516.

Harshbarger, K.E., Nevens, W.B., Touchberry, R.W., Lang, A.L. and Dungan, G.H. 1954 The yield and protein content of silage corn as influenced by fertilization. J. Dairy Sci., 37, 976 - 981.

Jahn, S.V. 1961 Feeding value of maize for silage treated with different amounts of fertilizer. Herbage Abstracts, 34, 233.

Kiesselbach, T.A. 1950 Progressive development and seasonal variations in the corn crop. Nebraska Agr. Exp. Sta. Res. Bull., 24, 2 - 49.

Nandpuri, K.S. 1964 Effect of different plant populations and nitrogen levels on the yield and protein content of corn silage. Herbage Abstracts, 34, 13.

Rutger, J.N. and Crowder, L.V. 1967 Effect of population and row width on corn silage yields. Agron. J., 59, 475 - 476.

Van Dobben, W.H. 1962 Influence of temperature and light conditions on dry matter distribution, development rate and yield in arable crops. Neth. J. agrie. Sci., 10, 377 - 389.

Compte rendus d'expérimentation ITCF et AGPM, années 1972, 1974 et 1975. Comparaisons pluriannuelles des caractéristiques fourragères des variétés

de maïs. Mise à jour 1972. ITCF - AGPM. Andrieu, J. 1976 Factors influencing the composition and the nutritive

value of ensiled whole crop maize. In: J.C. Tayler and J.M. Wilkinson (Editors), The Maize Crop as a Basic Feed for Beef Production. Animal Feed Science and Technology.

Animal Feed Science and Technology, 1 ( 1976) 273 -286 273 Elsevier Scientific Publishing Company. Amsterdam - Printed in The Netherlands

DISCUSSION ON SESSION 2

R.J. Wilkins UK

We have 35 minutes for discussion on these five papers. There has been much material presented that is of extreme interest to us and I am sure that each one of these papers is really worthy of the entire discussion period that we have. Let me pick out two or three themes or aspects that came up on more than one occasion before making the discussion period open.

Firstly, there was a tremendous accent in all the contri­butions we had on using the whole crop. This was the case in the contribution from Yugoslavia and from Spain, countries which, we were told earlier today,have been primarily growing maize as a grain crop. So I think we would see, as Savio' pointed out in his paper, "What is the point of growing it and then leaving 40% or so of the potential energy, dry matter that you have produced, in the field"? So, our speakers on crop production here were very concerned with the ways in which we could utilise all that they could grow. We had our eyes opened by Professor Blanco, to the possibility of mechanical fractionation of the stover of the crop. Later on in the conference we shall be coming back to these themes as to how, as nutritionists, we can use what is grown. Possibilities for alkali treatment and up­grading the stover, will, I am sure, feature in our later discus­sion this week. So, we are wanting to use as much of the crop as we can.

A second aspect is one of climate in relation to yield and quality. Here, not unnaturally, there were different problems highlighted as being the most important by our different speakers. We heard in Savie's and Monteagudo's papers about problems of drought stress and tolerance, moisture relations, in relation to growth. We did not really hear what the plant breeders thought they could do about improving the performance of maize under very dry conditions although there were indic­ations given from Savie that we really needed 250 - 350 mm of rain during the growing season. Ïhere was a suggestion from Spain that we could use a tensiometer to help us plan when we could inject more water into the system and therefore make

274 more efficient use of water in growing maize. These are aspects that we should come back to in discussion.

The speakers from further north in Europe were concerned more with growth at low temperatures and speed to ripening and maturation of the crop. We did not really hear of any progress being made or any activity in trying to identify maize genotypes that would grow at lower temperatures. This is something that we might, again, want to explore in this discussion. We did hear about the ways in which we could help in identifying areas suitable for growing maize and in more than one paper we were talking about accumulated temperatures, in Centigrade degrees, I believe, above a 70° minimum as a climatic index for growing maize. This is something on which there has been quite a lot of research activity and we may also want to spend more time thinking about growth in the early part of the life of the maize crop. One aspect that we have not begun to discuss is the relation between climate and the composition of the crop. Phipps was showing slides with in vitro "digestible organic matter in the DM", a very clumsy expression which we use in the UK a lot, values of 70 - 72. This means an organic matter digestibility of 75 for a whole crop of maize. We have felt for quite a long time that the digestibility of our whole crops, despite having a rather low grain content, tends to be higher than those grown in much of the United States and in southern Europe and it would be helpful to hear, particularly from people in southern Europe, as to what figure we are talking about for digestibility of whole crops of maize.

Turning now to other aspects of agronomy, the two things that we have clearly, and not surprisingly, spent time on - the questions of plant density and response to nitrogen fertiliser. In relation to plant density there does not really seem to have been any major agreement; we say that if we have got more water available for growth we can increase the plant population, if we are going to utilise the crop as a whole crop for silage rather than for grain, we will further increase level of population, and the highest figures that we were talking about were something in the order of 100 000 plants per ha. We may perhaps note that if we are saying that for growing for silage we increase plant population, we know that we are then

275 going to reduce the ear content, and this is perhaps implying some acceptance of a point that maximisation of grain content is not of the first importance in relation to silage crops.

Nitrogen fertilisers - there was an interesting point brought up by Savie this morning in talking about nitrogen fertiliser application with plants at the six to nine weeks stage. He was saying that nitrogen fertilising policy was being simplified, perhaps, in Yugoslavia; Phipps talked about the very low nitrogen fertiliser responses that have been obtained in Britain - they were really not much different from the figures that Andrieu suggested. So I would appreciate comments in a few minutes about the pattern of nitrogen fertiliser application in relation to the growth of maize. This is just trying to bring your minds back to points that we had brought to our attention in these papers.

I would now like to make the discussion open but I will suggest that we should be concerned here with climate, agronomy, genotypes in relation to yield and chemical and morphological composition (perhaps in vitro digestibility) but questions on the overall animal productive value of the crop and aspects specifically related to conservation will be better dealt with in later sessions.

D. O o s t e n d o r p Netherlands

May I comment on the question of nitrogen fertilisation and fertilisation in general in maize, the figures mentioned by Dr. Phipps, about 80kg of nitrogen, are very low by our standards and ideals since in relation to yields and content of nitrogen a good crop of maize in Holland requires about 180 - 220 kg of N/ha and the same refers to the UK. It is very important to take account of the soil content of nitrogen in relation to the amount of fertiliser that is needed. It is also important, of course, to consider the amount of other nutrients that are given in the form of slurry. In Holland for instance, for each tonne of slurry we calculate 2 kg of N, 2 kg of Ρ2°5

a n d 5 k9 of K_0,

so there are more factors involved than just the level of fertiliser.

276 R.J. Wilkins

Yes, do you have any observations on late application of fertiliser nitrogen, that is, summer applications to the growing crop in the way that Savie was describing?

D. Oostendorp

Yes, this amount, say 200 - 225 kg N/ha, is often given in two dressings.

R.J. Wilkins

The point made there is a very good one, that if you have got a crop - and in Britain we will be taking out at least 150 kg of nitrogen per ha with the crop - then that nitrogen has got to be supplied from somewhere. Do we have any more observations in relation to nitrogen fertiliser of the crop? Are there any countries where it is common to apply 200 kg of nitrogen to maize?

D. Lanari Italy

I am not an agronomist, but I know that in our country, to produce maize either for grain or silage production, we use a very high amount of nitrogen. We use up to 2 50 or 300 kg of nitrogen, this is done on fields where maize is cultivated year after year for up to 5, 6, and 7 years.

R.J. Wilkins

That's a situation where your soil nitrogen supply would be very small.

D. Lanari

Yes, so. I am a bit surprised that the figures mentioned are not higher.

277 R.J. Wilkins

Dr. Savie, I believe you referred to about 18Ö kg or some­thing of that order?

R. S a v i e Yugoslavia

Altogether we supply here for good high mature yield, about 300 kg of fertiliser nutrients. The ratio of N:P:K is 1.0:0.8: 0.6. that means 120 - 140 kg N/ha.

R.J. Wilkins

Just a clarification of that; by nutrients you mean P 30_ and K 20?

Yes.

R.H. Phipps UK

I will agree that there are obviously major differences in the fertiliser recommendations and the slide I showed was a summary of 17 separate fertiliser trials carried out in the UK from 1958 - 1974. I think only one had been published and I think the reason why the others had not been published is that the authors were expecting a big response to nitrogen under UK conditions - they did not get it and they thought there was something wrong with the experiment. However, when you add 17 experiments together and still come up with the same result then I think there are obviously factors which are at variance between the UK and other regions. Possibly one explanation maybe our lower soil temperatures in the spring which could restrict nutrient uptake of the NPK during the early stages of development with the maize crop. The other, possibly, may be that the inherent fertility of the UK soils may be higher but in one particular field which has grown 12 consecutive crops of barley, we could only show a response of up to 80 kg of nitrogen per ha when we grew maize. We just cannot get

278

experimental evidence to justify using more than about 80 kg of nitrogen per ha.

R.J. Wilkins

I think Oostendorp was right in drawing our attention to the balance between nitrogen in the crop and the total supply.

R.H. Phipps

Oh indeed, mineralisation of nitrogen from our soils would contribute up to 50 kg of nitrogen per ha which takes that up to a total of 130.

R.J. Wilkins

Thank you. Let us move on from nitrogen to another major input affecting the crop. This is water - irrigation. When you were talking about a tensiometer, were you thinking about an experimental technique or something that could be used practically?

A. Monteagudo Spain

Nobody uses it practically but, sometimes, we need the tensiometer for experiments; it depends on the class of soil.

R.J. Wilkins

In countries where you have big soil water deficits and you have irrigation available is the financial return for using water on maize very competitive with that from other crops? What is the situation in Spain and Yugoslavia?

A. Monteagudo

The use of water can be very complicated because in Spain for some periods of each year we need the water for drinking. One possibility is to move the time of sowing in relation to

279 the rainy period. We need more water. It is a question whether we have more déficiences in water with two crops than one crop and whether other crops can be used.

R.J. Wilkins

You suggest that growing other crops such as sorghum could be a solution. Is there any available variation within maize in relation to ability to extract water from the soil or to tolerate short periods of water stress?

J.L. Blanco Spain

We have no real figures about the efficiency of water utilisation, but we know that there is some interaction with the different factors involved. There are some places, for example, in the south, where the temperatures are very, very high and the efficiency of water use varies very much. This interaction between the different factors; nitrogen fertiliser, water,the date of planting, the number of plants per ha, and so on, depends very much on the genotypes Many of the genotypes react completely differently in efficiency of use of nitrogen, water and temperature and sometimes the reactions are quite different depending on the origin of the hybrid. When we changed the date of planting for the American hybrid, the reaction in production was very small. With the Spanish hybrid, we get a tremendous response to every planting. Sometimes it is 50% of the yield. The same happens with the number of plants per ha and with nitrogen. For example, in general the American hybrids produce only an extra 200 kg per ha to 400 kg per ha with a change of 20% in nutrition. With some Spanish hybrids the reaction is 60% plus. All these factors together make a tremendous difference and we cannot speak about the efficiency of the use of nitrogen or of temperature or water, we need to think of the efficiency of one hybrid, to produce the one with an optimum combination of factors. This is why it is very difficult to discuss this question. In other words, there is a very complicated interaction, a multi-factor situation with the reaction of any factor in relation to the others for each

280 type of hybrid.

R.J. Wilkins

So you would suggest that there is tremendous opportunity for fitting a genotype to a particular environment.

C. Lelong France

I am surprised that Phipps recommends sowing 150 000 plants per ha in early hybrids for silage production and ask why he suggests this, because one factor he did not mention was the lower content of DM as the density increases, and to make silage the DM content is an important limiting factor.

R.H. Phipps

The range of densities recommended for silage in the UK varies between 100 000 to 110 000 and when we go to the wetter western areas may be as high as 150 000. These densities are recommended in order to achieve near maximum DM production. The work at Cambridge has, in fact, shown that in that range, averaging 130 000 plants per ha, with the majority of hybrids used in the UK there is only a 1% or 2% unit difference in the DM content of our crops - no more.

M. Strickland UK

My question follows on from the previous one. Our problem on the heavy soil near Cambridge is really starting the crop off in the spring. We have heavy soil which takes a lot of time to warm up and we often· get disappointing results simply because the crop does not get started. I am wondering whether there is an opportunity for selecting genotypes that would, in fact, tolerate colder conditions in order to get a better start and a longer growing season in which to produce more yield.

281

E. Zimmer Hest Germany

I would like to ask Dr. Phipps a question. Can you give me the DM content, the figures, for 100 000 - 110 000 and 150 000 and below, let me say, 70 000 and 80 000 plants per ha, as we do in central Europe, the DM content of the whole crop?

R.H. Phipps

I cannot give you the exact figures at the moment, but I can give you several papers in which the DM content of the crops at a range of plant densities, is given. We find little difference in the DM content of our crops in that sort of range.

E. Ζ immer

What, approximately, is the range? In the morning we had figures from northern Germany, and Dr. Oostendorp from the Netherlands agreed, showing that we can reach 24% or 25% of DM in the whole crop. In going south, of course, we increase our DM content. I would like to hear the figures from the UK. Is it below 20%?

R.H. Phipps

No. The majority of crops harvested in the UK are in the region of 25% DM. In very bad years people have harvested at as low as 20%, but by and large 25% DM is what is achieved.

R.J. Wilkins

I think this is something in which there is tremendous variation from year to year in what is happening. We will have had some years recently which have been very cool during the autumn period and then, at any one date, there would have been very little difference between densities but all around the 20% DM mark. If we have a better year, rather more like those that you have in Braunschweig, at any date there would be a difference but if we are taking 25% DM for our guideline

282

figure, which has been the figure which we have tended to use in the UK, then the effects of differences in density would be some spacing out in the date of harvesting, perhaps with three weeks or so between the highest and the lowest density.

R.H. Phipps

Much, much less than that.

K.G. Mølle Denmark

I would like to put a question to anybody who would like to give a reply. Is it advisable to place phosphorus and nitrogen at the moment of sowing? In Denmark we have read about experi­ments indicating that if you place nitrogen/phosphorous fertiliser 5 cm or so from the maize seed when sowing you get better resis­tance to low temperatures in spring and early summer and you get good development; in this way a maize crop may have a higher DM content in September. Should this technique be recommended for the cooler climates, or is it a generally advisable technique?

R.J. Wilkins

I am looking for offers to respond to that question.

Normally, here in northern Yugoslavia we use phosphorus and potassium, before ploughing or at the latest opportunity before planting but not for the reasons you mention. This is only to spare transport and to spare time applying this fertiliser but whether maize will ripen better I do not know. For us it is just for economic reasons and we try to give the fertiliser twice.

R.J. Wilkins

Any comments on placement of fertiliser?

283

D. Oostendorp

The practice in Holland is to give the phosphate as a row application together with sodium at 5 cm. We think that is a good practice for the cold regions.

R.J. Wilkins

We have not managed to flush out any hard experimental data on this.

J.C. Tavler UK

There is another subject I would like to bring in at the request of a colleague, Mr. Gillot, who looks after the protein programme of the Commission. He would like to know whether any maize producers are interested in growing soya together with maize for silage and he also raises the question whether there is any interest, where the climate is suitable for two crops a year, in applying the American practice of growing a maize crop to be harvested in the immature stage for silage, followed by soya which is then harvested for grain.

E. 2 immer

Double cropping is s common practice in Germany, but it depends on the water availability. We normally use rye, or wheat, and then have the second crop as maize. If water is available then the double crop yield is more than the single yield of maize but very often the rye uses the water and the maize has insufficient water and then the total yield is no greater with double cropping. So, only in particular regions is it recommended.

R.J. Wilkins

I believe the practice of mixing high protein crops with maize has been something that in mid-European countries, certainly a few years back, was quite common.

284 R. Savie

Soya production in our country, especially in this part is uncertain. We try to mix for silage, but only for silage.

R.J. Wilkins

We might think of legumes other than soya, that might be more important to us.

K.G. Mølle

Concerning the double crop system, I can say that we have tried in Denmark, only a few times, to grow maize, not with soya but another sort of bean, but I reckoned there were no advantages in doing this. The maize grew poorer than without the bean and the bean itself did not increase the total yield so much that there was any interest, but that was under Danish conditions.

R.J. Wilkins

Our philosophy in the UK is generally along those lines, that we would do better to grow the crops separately and mix at the time of feeding rather than compromise the agronomy and cultivation of each individual crop.

C. Lelong

We heard in France of German maize forages that were rich in protein; is it true or not?

M. Zscheischler W, Pt Gi many

In Germany, we now have two varieties but they are not registered; they are in the second year of proving and we do not know the details.

285

R.J. Wilkins

This is grain maize?

M. Zscheischler

No, for forage. Professor Polimer at Hohenheim is breeding two varieties but nobody knows the value and there are even different figures about the difference in protein content at present. Last year was the first, and they were tested on about five sites in Germany but so far there are no official figures available.

Ch. V. Boucqué Belgium

Several speakers have mentioned the FAO Standards or Index. Can somebody explain that?

R.J. Wilkins

It is an index which is not used very widely in Britain and I was very impressed at how several authors here could use it, and I am sure we do want standards to help us discuss variety types.

M. Zscheischler

I want to explain it. In 1954 at Belgrade, there was a proposal to bring in these FAO Standards. These Standards are the same as in Wisconsin; we had check varieties like Wisconsin 255, Wisconsin 355A and Wisconsin 400, and so on. These are relative numbers; they have nothing to do with days from sowing to ripening. They go from 100 - 1 000, even 1 200. So we have a relative measurement for getting in a scale these different varieties. As far as Germany is concerned, we can only use, for grain, varieties between 190, or roughly 200, and 300. We have heard from Professor Savie1 that he has varieties of 600 and even later. In Georgia in the US they even have varieties of 1 000 and 1 200. Under our conditions in Germany

286 we feel that between 50 numbers there is a difference of about 6 - 8 days and also 6 - 8% DM content in the grain. However, there is quite a big difference in the different countries.

R.J. Wilkins

Also, if you have a new variety this is grown in particular environments in relation to standard varieties and then it is given a rating on this FAO scale?

J.M. Wilkinson UK

Mr. Lelong's paper gives some of the common European varieties along with their FAO Index numbers. One can get some idea from that.

R.J. Wilkins

Thank you all for keeping with us during this session and helping this discussion. In closing the session, I would like to thank again the five speakers who contributed.

287

SESSION III

EFFICIENCY OF HARVESTING AND CONSERVATION

Maximising nutrients harvested and made available to livestock as fresh, dried or ensiled whole crop or as ears or grain. Effects of date of harvest, dry matter content, additives, method of preservation, variety and chopping treatments on crop composition, fermentation of silage and wastage during storage and feeding. Methods of reducing wastage.

Animal Feed Science and Technology. 1 (1976) 289-299 2 8 9 Elsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands

EFFICIENCY OF HARVESTING AND CONSERVATION

E. ZIMMER Institut für Grünlandwirtschaft, Futterbau und Futterkonservier­ung der Forschungsanstalt für Landwirtschaft, D 3300 Braunschweig, Bundesallee 50, GFR.

ABSTRACT

Green maize (10 - 16% DM) contains about 550 - 590 g SE/kg DM; the whole crop cut at the milk to dough stage (20 - 30% DM) contains about 620 - 650 g SE/kg DM. Within each of these feeds nutritive value is largely independent of harvest time.

Genotype does not affect the nutritive value in general, and fertilisation will affect yield much more than nutritive value.

Specific, unavoidable losses resulting from the ensiling process are calculated to give a reduction of 30 - 50 g SE/kg DM. Losses reach 10 - 15%. Secondary fermentation, as well as aerobic processes caused by sub-optimal technology, will incur an additional reduction of 20 - 40 g SE/kg DM. Unstable silages will have a reduction of 10 - 30 g SE/kg DM from heating.

NPN additives in general improve the protein-energy ratio, 'as well as fermentation. There is a specific effect on stability The effects of late harvest and the nutritive value of sun-dried maize straw are discussed.

QUALITY OF FRESH MATERIAL

Stage of maturity Between milk and late dough stage, the nutrient concentration

shows only small variation and is independent of date of harvest (Table 1). Nevertheless, dry-matter content below 25%. means seepage problems and increasing risk of a lactic type of fermentation.

Energy content lies between 620 and 650 g SE/kg DM and digestible organic matter is 73 - 75%.

For so-called "green maize", made up mostly or exclusively of vegetative material, nutritive value ranges between 550 and 590 g SE/kg DM and DM content is below 18%.

TABLE 1 COEFFICIENT OF VARIATION FOR PARAMETERS OF NUTRITIVE VALUE

Author

Green material Demarquilly Schneeberger Thomson Cummins Davis and Bowden Giardini Rosenstiel Maize silage Dijkstra Schneeberger Gross

Country

France Switzerland UK USA Canada Italy FRG

Netherlands Switzerland FRG

Year

1969 1971 1968 1970 1968 1963 1962

1960 1968 1970

Parameter

DOM* DOM DOM in vitro DOM in vitro digestible energy UF/DM SE/DM

SE/DM SE/DM SE/DM

Stage of maturity

milk· - dough bloom - mature

late milk - mature milk - dough beg.milk - late dough milk - dough

DM (%)

22 - 30 -

18 - 35 25 - 37 16 - 26 19 - 38 20 - 30

1 3 - 2 0 16 - 35 12 - 31

Interval (d)

?

-70 -60 -30 -55 -35 -40

---

Coefficient of variation (%)

0.9 1.0 2.7 3.9 2.2 3.2 1.7

9.7 9.7 5.6

* Digestible organic matter

291

Calculation of energy content can be done by regression formulae, based on the parameter crude fibre (Demarquilly, 1969; Dijkstra and Becker, 1960; Schneeberger and Schoch, 1968) or dry matter (Gross, 1970; Gross and Averdunk, 1974; Zscheischler et al., 1974)

Genotype With respect to the available varieties at comparable stages

of maturity there is only a negligible effect of genotype. Exceptions are, for ruminants, new varieties high in lysine and new types becoming available with possibly higher digestibility of stalks and leaves and reduced lignification (e.g. brown mid­rib gene).

Fertilisation Fertilisation affects yield much more than nutritive value

(summarised by Zimmer, 1973). Increasing nitrogen application, for example, resulted in 12.3% and 12.6% variation respectively in SE or DM yield/ha, but only 1.5% for SE content (Primost, 1964) .

Epiphytic micro-organisms A specific epiphytic microflora is associated with maize

and is characterised by a high total number of micro-organisms, E. coli, and particularly, yeast (Koch et al., 1973).

THE ENSILAGE PROCESS AND NUTRITIVE VALUE

Fermentation In general the relationships between the ensilage process,

changes in nutritive value and extent of losses are known (Figure 1).

The production of fatty acids causes energy losses between 3.5% for lactic and 38% for acetic.

Some alcoholic fermentation seems characteristic with maize; this is DM-consuming but not energy-consuming; lower utilisation by animals seems possible (Laube, 1967) . Aerobic processes and/or secondary fermentation during storage depend mostly on technology and can be minimised. Heating during unloading depends on a

292

combination of the factors and micro­organisms; significant losses are possible and precautions are necessary. Seepage losses in highly digestible material occur if the DM content is below 25%.

From these points the unavoidable reduction of energy content is calculated to be 30 ­ 50 g SE/kg DM: digestibility decreases by around 2 ­ 5 units (Table 2); DM losses are in the range 10 ­ 15%.

TABLE 2 DIGESTIBILITY OF ORGANIC MATTER IN FRESH AND ENSILED MAIZE

Author

Andrieu Nehring Harris

Schneeberger

Year

1970 1972 1965

1971

η

16 5 4

4

Fresh

72.2 74.2 + 1.48 73.9 + 0.85

75.5 + 0.99

Silage

71.5 71.2 + 2.78 73.0 + 1.63

71.8 + 1.47

MATURITY­NUTRITIVE VALUE­ENSILING

SIE/ TS SE I DM

— frischer Mais / fresh corn Moissiloge / corn-s Hoge

Ι , ­

L « IS IS 20 22 2i 26 26 30 32 34

1301 TS­Geholl DM­ conteni

Figure 1

293 The previous statement on unavoidable losses or changes is based on the supposition that intensive homolactic fermentation took place supported by optimal technological conditions. Further factors have to be borne in mind.

Heterolactic or butyric type of fermentation results from suboptimal technology with extended respiration, high temperat­ures in certain climates and soiled or frozen material. These factors may reduce quality and cause higher losses as well as changes in energy content. Significant relationships between these parameters can be given (Hönig, 1972; Uchida and Sutoh, 1971; Zimmer, 1972), and an additional 20 - 40 g SE units/kg DM may be lost.

Technology There are close connections between organisation and/or

physical treatment and the biological process. Extended filling time by poor organisation or oversized silos extends respiration, wastes carbohydrates and increases the risk of heating during unloading. Specific data are not available.

Anaerobiosis is the basic requirement for good fermentation. The effect of aeration by leaky silos or unsuitable covering, on the other hand, becomes measurable via reduced quality and increased losses.

Positive effects of chopping to around 10 - 20 mm particle size are explainable by higher density and better disintegration of material (Hamm and Dijkstra, 1971; Zimmer, 1972). Modern techniques in principle now allow greater fineness even for mature material. Increasing fineness from 14mm to 4 mm by using a recutter does not produce a biological effect but rather a better utilisation of silo capacity (Table 3). However, this process results in an increase of over 200% in power require­ment (Hönig).

NPN-additive Effect of NPN on nutritive value, its application and dose,

are well known. Adding NPN also stabilises fermentation; a significant increase in lactic acid was observed, with normal or lower amounts of VFA (Gross et al., 1969; Shirley, 1972; Owen, 1971). In Germany, urea and Maisfertil (mixture with minerals) are in common use while Pro-sii, a liquid containing

TABLE 3 EFFECT OF CHOPPING TREATMENT ON MAIZE

Treatment

14 mm 7 mm 4 mm

Recutter

Density

relative

100 106 114 125

Org. VFA % of total

36 36 36 34

acids Lactic % DM

6.0 5.5 5.9 6.5

Los co0 % DM

3.7 3.7 3.4 3.1

ses Energy % total

7.6 7.2 8.3 7.4

Instab 4 day

relative

91 109 121 79

ility11

8 day relative

105 109 107 79

Grain ^ in silage

% DM

19.0 15.0 12.5 5.5

in faeces % DM

intake

-5.8 -2.2

Energy requirement KWh/1

-1.6 2.1 3.5

relative

-100 136 223

1) Instability: mean of 4 or 8 day losses = 100 2) Grain: untouched in faeces as % of DM intake

(Honig, 1975)

295 ammonia is under experimentation (König, 1975).

Heating and its effects The exothermic process of heating during unloading has been

studied fairly well up to now (Hönig, 1972, 1975; Morwarid, 1969; Beck and Gross, 1964; M.K. Woolford, unpublished, 1975).

As a result of both aeration and the increase of yeasts and bacteria to a critical population during the filling period, significant losses and a lowering of the energy content occur during unloading. Depending on time, DM losses rise to 5 - 15% or more (Figure 2). The reduction of SE concentration in unstable maize amounts to 10 to over 30 g SE/kg DM and protein decomposition begins.

HEATING OF MAIZE-SILAGE - EFFECT OF AERATION -

( C our reges. Honig. 1975 )

% ί δ ­

ιο Ui !" 2>o­I

5­

AERA Tl ON

/ ANAEROBIC

/ /

' f ­ | 1 1 1 1 1 1 1 — / 2 3 7 6 9 days

Figure 2

The inhibiting effect of organic acids such as propionic, acetic, even butyric, but not formic against fungal activity is well known. The application of acids to prevent heating has to be carried out during the filling of the silo and depends, for practical use, mostly on the price of the additive. New research

296

results, (Hönig, 1975) indicate the same effect by using either urea (Figure 3) or Pro­sil. The risk of heating was reduced significantly

Heating of maize-silage Effect of UREA (Honig ­3751

% 20

10 5. Q

0

/

//

s> //

100

I 50

■ without UREA ln = 19)

■ with UREA <n=t7)

0 12 3 4 5 7 9 days

\ %

­ _

'012345 7 9 days storage time

Figure 3

'Stalklage' and frozen maize After harvesting the ear the remaining stalks and leaves

provide an additional valuable product. Using this as 'stalklage' is very common in the USA (Colenbrander et al., 1971 a,b) and should be recommended in Europe too. Nutritive value depends on the maturity of the whole plant. Stalklage harvested after picking cobs in dough stage has an energy concentration of about 400 ­ 450 g SE/kg DM. Maize straw remaining after threshing has a digestibility below 55% and an SE concentration between 210 and 380 g/kg DM (Koch, 1971). For conservation one has to add water to achieve sufficient fermentation, and NPN is added.

The effect of early freezing has not been so thoroughly studied. Crude nutrient content will not change very much (Caldwell, 1971), but significant losses will occur. Gordon

297

(1968) observed DM losses of 19 ­ 27% of total yield­Digestibility decreases too and energy content was lowered by about 44 g SE/kg DM. Humid climatic conditions after freezing will be dangerous, because the epiphytic flora is shifting to proteolytic and coliforms and causes poor fermentation (Nehring, 1958; Wetterau, 1972). Dry climatic conditions have been found to cause a decrease of overall digestibility and reduction in energy of 20% (Melotti, 1969).

REFERENCES

Andrieu, M., 1970. Valeur alimentaire du Maïs­fourrage. Le maïs, plante fourragère ­ ITCF.

Beck, Th. and Gross, F., 1964. Ursachen der unterschiedlichen Haltbarkeit von Gärfutter. Das wirtschaftseigene Futter 10, No.4, 298 ­ 312.

Caldwell, D.M. and Perry, T.W., 1971. Relationships between stage of maturity of the corn plant at time of harvest for corn sllaqe and chemical composition. J. Dairy Sci. 54, 533 ­ 536.

Colenbrander, V.F., Muller, L.D., Watson, J.A. and Cunningham, M.D., 1971. Effects of added urea and ammonium polyphosphate to corn stover silages on animal performance. J. Anim. Sci. 33, 1091 ­ 1096.

Colenbrander, V.F., Muller, L.D., and Cunningham, M.D., 1971. Effects of added urea and ammonium polyphosphate on fermentation of corn stover silages. J. Anim. Sci. 33, 1097 ­ 1101.

Cummins, D.G., 1970, Quality and yield of corn plants and component parts when harvested for silage at different maturity stages. Agron. J. 62 781 ­ 784.

Davis, W.E.P. and Bowden, D.M., 1969. Effect of growth stage at harvest on the nutritive value of a grain corn grown for silage. Can. J. Plant Sci. 49, 361 ­ 370.

Demarquilly, C , 1969. Valeur alimentaire du maïs fourrages. I. Composition chimique et digestibilité du maïs sur pied. Ann. Zootech, le, 17 ­ 32.

Dijkstra, Ν.D., 1960, Digestibility and feeding value of green and ensiled maize fodder. Versi, v. LBK. Onderzoekingen 66, 14.

Giardini, Α., 1964. Ricerche sperimentali sulla foraggicoltura per insila­mento in torre. Estratto da progresso Agrie. 9/10, No. 7,9,11, and 12.

Gordon, C.H., Derbyshire, J.C. and van Soest, P.J., 1968. Normal and late harvesting of corn for silage. J. Dairy Sci. 51, 1258 ­ 1263.

Gross, F., Koch, G. and Koller, G., 1969. Harnstoff im Maisgärfutter.

298

Das wirtschaftseigene Futter 15, 210 ­ 227. Gross, F., 1970. Einfluss des Erntezeitpunktes auf den Futterwert von

Maisgärfutter. Das wirtschaftseigene Futter 16, 306 ­ 336. Gross, F. and Averdunk, G., 1974. Der Gehalt an Nährstoffen in Maissilagen,

ihre Verdaulichkeit und ihre Beziehungen zum Nährstoffgehalt. Das wirtschaftseigene Futter 20, 66 ­ 74.

Hamm, G.G. and Dijkstra, N.D., 1971. Effect of two different harvesting methods on the resulting fodder maize. Bedrijfsontwikkeling, Editie Veehoudenj 2, 53 ­ 55.

Harris, C.E., 1965. The digestibility of fodder maize and maize silage. Expl. Agrie. 1, 121 ­ 123.

Honig, H., 1972. Änderungen des Nährwertes von Gärfutter bei unterschied­licher Siliertechnik. Vortrag auf der 16. Jahrestagung der Gesellschaft f. Landbauwissenschaften in Bonn, Sept.

Honig, H., 1975. Umsetzungen und Verluste bei der Nachgärung. Das wirt­schaftseigene Futter 21, 25 ­ 32.

Koch, G., 1971. In Rintelen, P. Mais. Ein Handbuch über Produktionstechnik und Ökonomik, 219 ­ 246.

Koch, G., Morwarid, A. and Kirchgessner, M., 1973. Zum Einfluss der Mikro­organismen der Maispflanzen auf die Stabilität der Silagen. Das wirt­schaftseigene Futter 19, 15 ­ 20.

Laube, W., 1967. Zur Problematik der Silierung zuckerreicher Futterstoffe unter besonderer Berücksichtigung der Alkoholbildung. Tagungsberichte Nr. 92 der DAL, Berlin, 169 ­ 176.

Melotti, L., 1969. Determination of the nutritive value of maize silage and sun dried maize fodder in a trial on digestibility. Boletim de Industria Animal 26, 335 ­ 344.

Morwarid, Α., 1969. Silierversuche zur Stabilität von Maissilagen. Dissertation Weihenstephan.

Nehring, K. , 1958. Über Probleme der Einsäuerung von Maisgärfutter und Grünmais. Deutsche Landwirtschaft 9, 483 ­ 488.

Nehring, K., 1972. Futtermitteltabellenwerk. VEB Dt. Landw. Verlag, Berlin. Owen, F.G., 1971. Silage additives and their influence on silage fermentation.

Proc. Int. Silage Res. Conf. Washington DC, 79 ­ 112. Primost, E., 1964. Ertrag und Qualität von Silomais in Abhängigkeit von

N­DÜngung und Witterung. Das wirtschaftseigene Futter 10, 10 ­ 21. Rosenstiel, F., 1966. In Liesegang, F. KTBL Kalkulationsunterlagen für

Betriebswirtschaft 3, M.10. Schneeberger, H. and Schoch, W., 1968. Untersuchungen über den Futterwert

von Mia

299

von Maissilagen. Schweiz. Landw. Forschung VII, H.3/4, 337 - 361. Schneeberger, H., 1971. Das wirtschaftseigene Futteraktuelle Probleme der

Verwertung. Schweiz. Landw. Monatshefte 49, 213 - 225. Shirley, J.E., 1972. Influence of varying amounts of urea on the fermentation

pattern and nutritive value of corn silage. J. Dairy Sci. 55, 805 - 810. Thomson, A.J. and Rogers, H.H., 1968. Yield and quality components in maize

grown for silage. J. Agrie. Sci. Camb., 71, 393 - 403. Uchida, S. and Sutoh, H., 1971. Untersuchungen über die chemische Zusammen­

setzung und Qualität von Silage. IX. Beziehung zwischen Qualität und Futterwert. Sei. Rep. Fac. Agr. Okayama Univ. 38, 51 - 58.

Wetterau, H., 1972. Silageherstellung. VEB Dt. Landw. Verlag Berlin. Zimmer, E., 1972. Ernte und Konservierung von Silomais. Hann. Land- u.

Forstw. Zeitung 125, Nr. 42. 8-10. Zimmer, E., 1973. Nährwert von Mais in frischem, siliertem und getrocknetem

Zustand. Europaische Vereinigung für Tierzucht, Wien (Manuskript) Zscheischler, J., Gross, F. and Hepting, L., 1974. Einfluss von Schnittzeit,

Sorte, und Standweite auf Ertrag und Futterwert von Silomais. Bayerisches Landw. Jahrbuch 51, 611 - 636.

Animal Feed Science and Technology. 1(1976) 301­311 301

Itlsevier Scientific Publishing Company, Amsterdam ­ Printed in The Netherlands

INFLUENCE OF ENSILING MAIZE EARS AND GRAIN ON CHEMICAL COMPO­SITION, CONSERVATION LOSSES AND DIGESTIBILITY

R. PARIGI­BINI and G.M. CHIERICATO Istituto di Zootecnica ­ Universita di Padova, Italy

ABSTRACT

No marked variation in proximate composition was observed during the ensiling of maize ears and grain. Silages had a significantly lower level of insoluble Ν and a higher level of NH­ and urea Ν than fresh products. The production of organic acid declined very rapidly in maize silages as dry matter con­tent increased.

Percentage losses in ensiling were very small, except for insoluble N. Data suggest that reduced fermentation and con­servation losses take place when dry matter content of maize ears and grain increases above 65 and 70% respectively.

Apparent digestibility of nutrients and energy of maize ears and maize grain silage appeared to be strongly affected by the dry matter content at ensiling time, the coefficients being higher when dry matter was lower.

INTRODUCTION

The harvesting and storage of high moisture cereals has be­come both practical and widespread during the past ten years.

According to the present conditions in Italy and in other European countries, this trend might be expected to continue to increase in the future.

Ensiling is the technique more commonly used, but recently the storing of high moisture grain has been increased by the use of chemical preservatives, such as organic acids.

The objectives of this paper are to summarise and briefly discuss some recent results of research on the ensiling of ground, high­moisture maize ears and grain with reference to the effect on chemical composition, conservation losses and nutritive value.

302

INFLUENCE ON CHEMICAL COMPOSITION

Before discussing the effect of ensiling on chemical composition of maize ears and grain, it is opportune to point out that chemical composition is strongly affected by the stage of maturity of the maize. Thornton et al. (1969a,h), found that the increase in dry matter content of ears and grain from early milk to mature stage, was assoc­iated with changes in chemical composition and nutritive value.

With advancing maturity, ether extract and NFE percent­age increased and crude fibre and ash decreased.

Little information is available on the chemical modi­fication of ears and grain during ensiling.

Results of two experiments performed in our Institute on ground maize ears ensiled at two different moisture levels, using the "buried bags" technique, are given in Table 1.

In general, no marked variation in proximate compo­sition was observed during ensiling.

The DM content seemed not to be much affected, but in our first trial there was a small but significant decrease in DM percentage.

The most important and significant variation concerned the Ν fractions and organic acid production. Ensiled maize ears had significantly (P^O.Ol) lower levels of insoluble Ν than the fresh product (88.7 vs 95.2% of the total N) and higher levels (P^O.05) of ammonia and urea Ν (0.5 vs 1.1% of total N).

303

TABLE 1 EFFECT OF ENSILING ON COMPOSITION OF MAIZE EARS - (% OF DM)

References:

No. of samples DM Ci) Crude protein (Nx6 Ether extract Crude fibre Ash NFE Insoluble Ν <2)

NH3-N+urea-N (2)

PH Acetic acid Lactic acid

Bo

25)

isembiante Fresh

o 77.2 9.6 4.1 5.2 1.5

79.6 95.2 0.5 6.0 -

-

et al., 1974b .Silage

9 76.6* 9.6 3.8 4.0 1.5

81.1 88.7** 1.1* 5.2** 0.13 0.14

Rioni,M and Fresh

6 68.0 8.9 4.1 8.5 1.5 77.0 -

-

-

-

-

Lanari, D (1) Silage

6 68.2 8.9 4.0 6.3 1.5

79.5 -

-

4.3 0.24 0.47

(D- Personal communication 1976 (2) - % of total Ν * - P<0.05 ** - Ρ <0.01

The pH value declined from 6.0 in the fresh maize ears to 5.2 in the high DU silage and to 4.3 in the lot· DM silage.

The data reported in Table 2, obtained in two different experiments performed in our Institute, indicate a similar trend in ensiled ground maize grain.

The sole significant variation cpncerns N^-N+urea-N (0.6 vs 1.0% of total N, in the fresh and ensiled grain respectively), pH value (6.2 vs 4.9) and acetic and lactic acid production.

The above mentioned data, regarding both maize ears and grain, suggest that little fermentation took place, because moisture was inadequate to support a more active fermentation.

In fact, other authors found more variation and fermentation when ensiling maize ears and maize grain of higher moisture content.

Baldoni et al. (1970) found from 1.8 to 3.1% of NH3-N in the total N; 0.4 - 0.5% of acetic acid in the DM and 0.9 to 2.7% of lactic acid in the DM in maize ear silage containing from 65.3 to 69.6% Df'.

pH

Acetic ac

%DM

Lactic ac

%DM

5.5

5.0

4.5

4.0

3.5

0.6

■0.4

0.2

0

2.0

• 1.5

1.0

0.5

0

Ear silage Grain silage

55 60 65 70 75 '//. D-

65 DM

70 75 % DM

80

Figure 1 Effect of DM Content on Organic Acids and pH of Maize Silage REFERENCES · Rioni and Chiericato, 1972; Δ Thornton et al. 1969a; OBonserabiante and Parigi-Bini, 1972

ABaldoni et al., 1970; D Bonsembiante et ai., 19/4a; ■ Bonsembiante et ai., 1974b X Lanari and Rioni, 1976; O Klosterman et ai., 1960.

305

D a n l e y and V e t t e r ( 1 9 7 4 ) s h o w e d more e x t e n s i v e f e r m e n t a t i o n

when m a i z e g r a i n w a s e n s i l e d a t h i g h e r m o i s t u r e l e v e l s .

The d a t a r e p o r t e d i n T a b l e 1 and 2 and r e s u l t s p u b l i s h e d b y

o t h e r a u t h o r s , c l e a r l y d e m o n s t r a t e t h a t DM c o n t e n t a t e n s i l i n g

t i m e i s o f m a j o r i m p o r t a n c e i n r e g u l a t i n g t h e f e r m e n t a t i o n p a t ­

t e r n o f m a i z e e a r s and g r a i n .

TABLE 2

EFFECT OF ENSILING ON COMPOSITION OF MAIZE GRAIN ­ (% OF DM)

References :

No. of samples DM (%) Crude protein (Nx6 Ether extract Crude fibre Ash NFE Insoluble Ν (2)

NH3­N+urea­N (2)

pH Acetic acid Lactic acid

Bon

.25)

sembiante Fresh

9 77.8 9.7 4.6 2.5 1.4 81.8 93.3 0.6 6.2 ­

­

et al., 1974b Silage

9 77.6 9.5 4.3 2.2 1.5

82.5 92.0 1.0* 4.9** 0.13 0.13

Rioni,M and Fresh

6 71.9 9.6 4.9 4.2 1.7

79.6 ­

­

­

­

­

Lanari,D (1) Silage 6 71.5 9.6 4.8 3.5 1.7

80.4 ­

­

4.1 0.17 0.69

(1) ­ Personal communication 1976 (2) ­ % of t o t a l Ν

* ­ Ρ < 0 . 0 5 ** ­ P < 0 . 0 1

In Fig. 1, data concerning pH and organic acids are plotted against DM content of maize ears and grain.

As the DM percentage increases, the lactic and acetic acids decrease and pH value increases. In the maize ear silage, lactic acid decreases from about 1.5% to r>.2% of DM; acetic acid falls from about 0.5% to 0.1% of DM; and pH value rises from 3.8 to 5.2, as the DM increases from 5P% to 75%

The production of organic acids (namely, fermentation) de­clines very rapidly when the Dì* content of maize ears increases above 65%. Particularly, the lactic acid content in the DM falls below 1% and pH value rises towards 5.0.

A similar trend can be observed in maize grain silage, when

306

DM percentage goes over 70%. The cell wall composition of both silages is presented in

TABLE 3 CHEMICAL COMPOSITION OF MAIZE SILAGES (Van Soest method)

DM CWC ADF Hemicellulose Cellulose Lignin

t.

» « 'a

* '*

DM DM DM DM DM

Ma ize ear

71.2 14.9 5.4 9.5 4.4 0.9

si lage Maize grain silage

73.5 10.2 2.6 7.6 2.1 0.5

Reference: Bonsembiante et al.. 1974a

As expected, the maize ears contained more CWC, ADF, cellu­lose and lignin. Other analyses performed on maize ear silage by Rioni and Chiericato (1972) showed higher CWC and ADF (21.1 and 8.9­0 of DM respectively) because the ear, harvested by a different method, contained more cobs.

Data on mineral composition are reported in Table 4. In both silages, the Ca, Ρ, Mg, Κ, Μn, and Cu levels were not different from those reported by NAS ­ NRC (1969) . The Na content was lower and Zn higher. The Fe level in maize ear silage was lower than the NRC value, but similar to the one found by Piva et al. (1974). TABLE 4 MINERAL COMPOSITION OF MAIZE EARS AND GRAIN SILAGES (% or ppm of DM)

No. Ca Ρ Na Mq Κ

of samples * 'i

% ■:,

t

Ma ize ear sil

3 0.042 0.290 0.006 0.113 0.410

age Maize g rain silage

3 0.018 0.320 0.006 0. 113 0.320

307

TABLE 4 (Cont)

Mn Zn Fe Cu

ppm ppm ppm ppm

Maize ear

5.4 20.3 47.3 3.5

silage Maize grain silage

4.3 25.0 29.5 ' 2.5

Reference: Bonsembiante et al., 1974b

ENSILING LOSSES

The results of two experiments, where the percentage losses during the ensiling of maize ears and maize grain containing about 77% of DM were measured by the "buried bags" technique in plastic silos, are shown in Fig. 2.

In both silages, the DM and 0M losses were very small and similar to those observed by Baldoni et al. (1970) in maize ears (67% DM) ensiled in a tower silo. According to the same authors, the DM losses were higher (2.7 ­ 3.2%) in a trench silo and a plastic bag silo.

The insoluble Ν showed losses (8.6% in ensiled maize ears and 3.8% in ensiled maize grain), with corresponding gains in NH3­N+urea­N (Fig. 2).

The above percent losses and those reported by Chandler et al. (1975) appear to be modest and were measured on silages of re­latively high DM content.

In such conditions, extensive fermentation does not take place and it agrees with data presented in Fig. 1, showing that fer­mentation increases when DM percentage of maize ears goes below 65%

APPARENT DIGESTIBILITY

Data on apparent digestibility of nutrients and energy of ensiled maize ears and grain, are shown in Table 5.

Digestibility trials were performed on young bulls receiving 1.3 ­ 1.5% of their body weight of a diet containing 90% of maize ears or grain and 10% of a protein, mineral and vitamin supplement.

Dry matter

Organic matter

Total Ν

Insoluble Ν

Ether extract

Total carbohydrates

NH3-N + u r e a - Ν

40 80 120

ear silage

grain silage

10 losses

160 200 % g a i n

Figure 2 Percent Losses in Maize Silage REFERENCE Bonsembiante et al., 1974b

309 Digestibility of both silages was calculated indirectly.

The apparent digestibility of nutrients and energy appears to be strongly influenced by the DM content of ear silage, the coefficient being higher when the DM was lower (Ρ<Ό.01).

TABLE 5

APPARENT DIGESTIBILITY OF ENSILED MAIZE EARS AND GRAIN OF DIFFERENT DM CONTENT

DM (%) No. of animals Apparent digestibility (%) DM OM Crude protein

(Nx6.25) Ether extract Total carbohydrate Energy CWC ADF Hemicellulose Cellulose

Maize ear silage *

63.2 4

83.3 84.5

61.9 84.4 86.8 81.7 ­

­

­

­

** 71.1 8

74.5 75.5

51.1 67.8 78.7 71.4 55.4 46.7 60.8 48.3

Maize grain silage * •

73.5 8

83.0 83.9

57.8 72.8 87.7 80.5 71.5 62.2 76.5 63.4

REFERENCES: * Bonsembiante and Par ig i ­Bini , 1972 ** Bonsembiante et a l . , 1974a

Recen t r e s u l t s of L a n a r i and R i o n i (1976) c o n f i r m t h i s t r e n d .

The d i f f e r e n c e can p r o b a b l y be e x p l a i n e d by t h e more f a v o u r ­

a b l e c h e m i c a l c o m p o s i t i o n of immature e a r s a t e n s i l i n g , t i m e . In f a c t , w i t h a d v a n c i n g m a t u r i t y , t h e CWC of cobs i n c r e a s e s and t h e d i g e s t i b i l i t y d e c r e a s e s (Thorn ton e t a l . , 1 9 6 9 b ) .

F u r t h e r m o r e , s e v e r a l a u t h o r s showed h i g h e r d i g e s t i b i l i t y of h i g h m o i s t u r e , t h a n m a t u r e , maize k e r n e l s (McLaren and Matsush ima , 1968; Tonroy e t a l . , 1 9 7 4 ) .

F u r t h e r m o r e , h i g h m o i s t u r e e a r s a r e f e rmen ted t o a g r e a t e r e x t e n t t h a n low m o i s t u r e e a r s , and t h a t can c o n t r i b u t e t o improve

310

digestibility. From the above discussion it can he concluded that reduced

fermentation and conservation losses take place in maize ears and grain ensiled at relatively high DM content (i.e. more than 65?, or 70% DM). At the same time, digestibility appears to be lower than in silages with higher moisture content.

Therefore, the choice of DM content at ensiling time, when not imposed by climatic conditions, will depend upon utilisation in animal feeding (level of nutrition, roughage to concentrate ratio, etc.).

However, ensiling seems to be the more suitable conservation technique for high moisture maize, in relation to present high drying costs.

REFERENCES

Baldoni, R., Giardini, A. and Vecchiettini, M., 1970. Ricoveri, Silomais e "pastoni" nell'allevamento del vitellone - Informatore Agrario, 28, 2247.

Bonsembiante, M. and Parigi-Bini, R., 1972. Ricerche sulla digeribilità e sul valore nutritivo del mais. Effetto del trattamento idrotermico della granella e della conservazione in silo della spiga umida. Alimentazione Animale, 1/33.

Bonsembiante, M., Rioni, M., Parigi-Bini, and Chiericato, G.M., 1974a. Ricerche sui pastoni di mais nella produzione del vitellone. Revista di Zootecnia e Veterinaria, 2, 97.

Bonsembiante, M., Parigi-Bini, R., Cesselli, P. and Chiericato, G.M., 1974b. Modificazioni chimico-nutritive e perdite di insilamento del foraggio di mais ceroso e dei "pastoni" di pannocchia e di granella. Revista di Zootecnia e Veterinaria, 6, 477.

Chandler, P.T., Miller, C.N. and Jahn, E., 1975. Feeding value and nutrient preservation of high moisture corn ensiled in conventional silos for lactating dairy cows. Journal of Dairy Science, 58, 682.

Danley, M.M. and Vetter, R.L., 1974. Artificially altered corn grain har­vested at three moisture levels. I. Dry matter and nitrogen losses and changes in the carbohydrate fractions Journal of Animal Science, 38, 417.

Klosterman, E.W., Johnson, R.R., Scott, H.W., Moxon, A.L. and Van Stavern, J., 1960. Whole plant and ground ear corn silages, their acid content, feed­ing value and digestibility. Journal of Animal Science, 19, 522.

311

Ulnari, D. and Rioni, M. 1976. Rate of growth, feed utilisation and digest­ibility observed with diets containing ensiled maize grain or maize ears fed alone or in mixtures. In J.C. Tayler and J.M. Wilkinson (Editors) The Maize Crop as a 3asic Feed for Beef Production. Animal Feed, Science and Technology

NAS and NRC, 1969. United States ­ Canadian tables of feed composition. Pubi. 1694, NAS, Washington, DC.

McLaren, R.J. and Matsushima, J.K., 1968. Digestion of ensiled reconstituted corn. Journal of Animal Science, 27, 1171.

Piva, G., Maroadi, Α., Santi, E. and Amerio, M., 1974. Sulle variazoni del pastone di mais, diversamente corretto, nel corso dell'insilamento. Alimentazione Animale, 1/37.

Rioni, M. and Chiericato, G.M., 1972. Impiego del "pastone di pannocchia", della pannocchia secca di mais e del fieno di erba medica e di loietto nella produzione del vitellone. Alimentazione Animale, 11/25.

Thornton, J.H., Goodrich, R.D. and Meiske, J.C., 1969. Corn maturity. I Composition of corn grain of various maturities and test weights. Journal of Animal Science, 29, 977.

Thornton, J.H., Goodrich, R.D. and Meiske, J.C, 1969b. Corn maturity. Ill Composition, digestibility of nutrients and energy value of corn cobs and ear corn of four maturities. Journal of Animal Science, 29, 987.

Tonroy, B.R., Perry, T.W. and Beeson, W.M., 1974. Dry,ensiled high­moisture, ensiled reconstituted high­moisture and volatile fatty acid treated high­moisture corn for growing­finishing beef cattle. Journal of Animal Science, 39, 931.

Animal Feed Science and Technology. 1 (1976) 313-326 3 1 3

Elsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands

EFFECT OF MAIZE SILAGE HARVEST STAGE ON YIELD, PLANT COMPOSITION AND FERMENTATION LOSSES

A. GIARDINI, F. GASPARI, M. VECCHIETTINI and P. SCHENONI C.N.R. Centro di Studio per la Conservazione dei Foraggi, Agronomy Department, university of Bologna, Italy.

ABSTRACT

A two year trial was conducted in the southern Po river valley (near Bologna) , in order to define the optimum harvest stage for maize silage under various cropping conditions (water availability, hybrid earliness).

Maximum green fodder yield was reached, for all treatments, at the milk stage, 20-22 days after flowering, with a whole plant DM content of about 20-21%. ,. On the other hand, maximum DM yield was reached at 40-45 days after flowering at a whole plant DM content of 42% and 38% for maize grown on irrigated and unirrigated land, respectively.

Differences between hybrids were only apparent in unirrigated conditions where between the early and late hybrids again a range from 42% to 38% in whole plant DM content was observed, but with a delay of about a week for the former.

Forage chemical composition, determined for the irrigated crop only, generally improved with the'delay in harvest, mainly because of a reduction in crude fibre and an increase in N-free extract.

In order to study the effects of harvest stage, i.e. of forage DM content, on the storage process, the experiments conducted during the last ten years at the "Centro Conservazione Foraggi" were elaborated. With the delay in harvesting the DM storage losses and the maize silage acid content decreased linearly, whereas the pK value increased. For high moisture grain and ear, except for the non-significance of DM losses, the same trend was recorded.

The results of this research, finally, indicate the advantage of harvesting at the maximum crop yield stage, there­fore after dough ripeness.

314 INTRODUCTION

Among the several aspects concerning the use of maize silage in beef cattle production, the choice of the right forage harvest stage represents, without a doubt, one of the most incisive factors for technical and economic results. In practice this involves the identification of the maturity stage which represents the best compromise between quantity and quality of production.

After flowering and up until dough stage ripeness, the maize plant has a really surprising productive potential (up to and more than 300 kg/ha/day) and an equally surprising dynamism on the forage quality because of the rapid modification in the ratio among the plant components. This means that to harvest too early or too late, even by just a few days, always causes considerable losses; in the first case a lower DM yield, in the second a quality deterioration.

The terms of the problem, however, are not very simple since numerous investigations showed noticeable differences in pro­ductive (Caldwell and Perry, 1971; Cántele and Giardini, 1966; Cummins, 1970; Geasler et al., 1967; Giardini, 1969; Giardini and Toderi, 1964; Johnson et al., 1966; Nelson et al., 1969; Perry et al., 1968; Pollacsek and Caenen, 1970), qualitative (Andrieu, 1970; Cummins, 1970; Giardini and Toderi, 1964; Johnson et al., 1966; Owens et al., 1967) and Storage processes (Andrieu, 1970; Gordon et al., 1968; Nelson et al., 1969), depending on the maize silage harvest stage. The variability in these results permits us to forecast that the optimum harvesting stage is closely connected to pedo-climatic factors and to the cultural practices adopted, and suggest that this problem has to be pursued in single environments.

Our field trials were conducted for two years on a fertile loam-clay soil on the southern Po river plain (near Bologna). According to Emberger (1933), these areas are classified as a temperate Mediterranean climatic zone with almost 50% of semi-arid type years, since the total summer rainfall (June, July, August) does not exceed 110 mm (Mancini, 1941). In this period the mean daily evaporation from a "Class A" pan is normally 5.7 mm/day. The unirrigated maize crop presents higher risks

315 because of drought damage and it is usually watered 2­3 times, depending on the rainfall trend.

We studied the effect of the harvest stage in relation to irrigation and hybrid earliness (2 hybrids: Dekalb 61, FAO class 300; Funk's G77, FAO class 600), the former in order to evaluate the different water availability effects, the latter to verify the influence of the temperature which is higher during the early hybrid's ripeness.

Recordings began at flowering and continued at weekly intervals until grain maturity.

EFFECT OF STAGE OF MATURITY ON YIELD

The comparison between irrigated and unirrigated land on the average data for hybrids is illustrated in Figure 1. The interaction of hybrid earliness χ harvest stage was also sig­nificant owing to the hybrids' different trend on unirrigated land (Figure 2).

The highest green fodder yield was reached at the milk stage, about 20 days after flowering and with 22­23% whole plant DM content. After this the forage yield decreased almost linearly up to combine­maturity.

In optimum soil moisture conditions the green fodder yields at flowering and at the dough stage were approximately the same, around 80% of the maximum yield. Instead, in the unirrigated environment the green fodder yield at flowering was lower and the rate of decrease following the milk stage was less accentuated. This trend was particularly evident in the early hybrid whose yield at flowering barely reached 70% of the maximum, whereas at the dough stage it still retained a yield level around 95%.

The reduction in green weight following milk ripeness was due almost exclusively to a weight loss by the plant's vegetative components, whereas the ear (grain + cob) maintained its weight almost unaltered (about 25% of the maximum green fodder yield) for the whole period until combine­maturity.

Maximum DM yield was found 8­10 days after the dough stage with a DM content of around 40% in the whole plant and 60­62% in the grain. In unirrigated conditions, particularly with the

316

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318 early hybrids, the maximum yield stage was delayed by about a week.

In the following stages a certain decrease in the DM production was noted to be due to loss of leaves and ears, breaking of tassel and corn borer damage.

The increase in DM yield after flowering was due to the growth of the ear and especially of the grain, whereas the plant's vegetative components remained at the yield level reached at flowering with a slight increase up to the milk stage and a certain decrease after dough ripeness.

The maize plant's growth rate after flowering is really surprising. During the first 40-4 5 days, i.e. up to the dough stage, the plant produces, in fact, about 60% of the total DM yield; a productive potential, therefore, which is double that recorded in the period preceding flowering.

The ear yield increases almost linearly up to the dough maturity; at this stage the grain DM yield is about 90% of the maximum yield which will be reached at physiological maturity, with lower values on irrigated land and for the early hybrids.

It is very interesting to consider some of the indicative parameters which can be used for production forecast purposes. Among these and with reference to the irrigated environment, the following should be remembered:

Maximum DM yield = Divisor green fodder yield at flowering or at dough stage : 2.6 green fodder yield at milk stage Maximum ear DM yield = green fodder yield at flowering or at dough stage green fodder yield at milk stage maximum DM yield Grain DM yield = green fodder yield at flowering or at dough stage green fodder yield at milk stage maximum DM yield Shelled grain yield (15.5% moisture) = green fodder yield at flowering or at dough stage green fodder yield at milk stage maximum DM yield

3.4

6.0 6.5 1.9

7.2 7.8 2.3

6.2 6.7 2.0

TABLE 1 DRY MATTER CONTENT AND PLANT COMPOSITION FOR FIVE CHARACTERISTIC MATURITY STAGES

Treatments

Irrigated land

Non-irrigated land

Early hybrid (non-irrigated land)

Medium late hybrid (non-irrigated land)

Stages of maturity

flowering milk stage dough stage physiological maturity combine-maturitj

flowering milk stage dough stage physiological maturity combine-maturitj

flowering milk stage dough stage physiological maturity combine-maturity

flowering milk stage dough stage physiological maturity combine-maturiti

Whole plant 15.5 20.9 34.1 47.6 51.8

16.4 22.0 33.0 43.3 48.0

16.8 22.4 33.7 44.0 48.3

16.3 21:2 33.4 43.8 48.7

% Stalk

14.3 18.0 21.7 26.6 29.6

14.8 18.5 21.3 23.5 24.2

13.7 19.0 22.0 24.4 25.0

16.0 17.9 21.0 22.2 25.8

of dry matter Leaf

22.2 24.0 32.3 57.2 61.8

22.9 27.0 32.3 44.9 52.2

23.1 26.0 31.8 41.4 51.2

21.8 28.0 32.3 48.0 54.0

Husk

13.8 19.3 30.1 47.1 51.7

12.5 19.3 28.0 46.6 51.6

13.0 17.2 25.8 45.4 50.0

11.9 20.3 30.1 49.2 54.3

Cob Grain

23.2 43.0 54.5 47.3 66.9 50.3 71.5

24.6 38.8 53.7 47.5 67.4 54.1 71.3

26.0 37.7 52.5 47.7 63.6 49.6 68.9

22.3 40.0 53.4 47.0 71.3 58.0 74.1

% Sk.

60 43 38 36 36

56 41 36 35 36

55 39 36 33 33

57 42 37 37 37

in green fodder Lf.

21 18 17 13 11

25 18 20 19 17

26 18 19 17 17

25 18 21 18 17

Hk.

19 13 8 6 6

19 15 10 6 7

19 17 11 6 6

18 14 9 6 8

Cob Gn.

26 9 28 10 35 11 36

26 11 23 11 29 10 30

26 11 23 10 34 11 33

26 11 22 13 26 10 28

Sk.

55 38 24 20 21

51 35 23 19 18

47 35 24 18 17

56 35 23 19 19

% in Lf.

30 20 16 16 13

35 22 19 19 18

38 21 18 17 18

33 24 20 21 20

dry Hk.

15 13 7 6 6

14 14 8 7 7

15 14 8 7 6

11 13 8 7 7

matter Cot

11 10 11

12 12 11

12 11 11

13 12 12

Gn.

29 42 48 49

29 38 43 46

30 38 47 48

28 36 41 42

320 EFFECT OF STAGE OF MATURITY ON FORAGE QUALITY

As the plant ripening process continues, and with the increase in DM content, the ratio between plant components is progressively modified toward the grain fraction. This trend (Figure 3 and Table 1) is more accentuated in the stages immediately after flowering and decreases progressively after the dough stage. Thus, whereas the grain at milk ripeness only represents 15-16% of the forage dry weight (estimated value), at the dough stage this value increases to 40-42% until it reaches almost 50% at physiological maturity. On unirrigated land and above all for the late hybrid, which is notoriously more sensitive to drought, the forage grain content proves to be lower (5-8% less).

This trend also occurs with regard to the green weight proving that, at least under our trial conditions, water availability and hybrid earliness effects showed little influence on the changes in the DM content of plant components. The DM% variation in the whole plant is, therefore, mainly due to variations in the ratio between plant components rather than to the different DM% of each part. It also follows that the whole plant DM% shows a certain variability and, at a given growth stage, it proves to be greater the higher the grain content of the forage.

Therefore this parameter is not sufficiently predictive for the evaluation of the plant's different stages and in particular for the identification of the crop's maximum yield stage.

In our trials DM% value varied by 42% in the irrigated crop and by 38% in the unirrigated crop and the same difference was shown in this latter environment between the early and late hybrid.

Even other parameters advised by some authors, such as the grain DM%, the grain content in the green fodder and on the ear, proved to be of little diagnostic value since they varied with the environment and with plant earliness.

As plant ripening proceeds, the chemical composition of the forage also changes, mainly according to the modifications in the ratio between the different plant components, rather than

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to the analytical variations of the same in the different vegetative stages (Table 2 and Figure 3). In fact, the only significant differences were in the reduction of the N­free extract and reducing sugars in the stalk, of sugars and fibre in the ear and of the crude protein in the leaves, and the increase in N­free extract of leaves and ear.

CHEMICAL COMPOSITION FOR FIVE CHARACTERISTIC STAGES OF MATURITY (IRRIGATED LAND)

Plant components

Stalk

Leaf

Ear (husk + cob + grain)

Whole plant

Stages of maturity

flowering milk stage dough stage physiological maturity combine-maturity

flowering milk stage dough stage physiological maturity combine-maturity

flowering milk stage dough stage physiological maturity combine-maturity

flowering milk stage dough stage physiological maturity combine-maturity

Crude protein

7.0 4.0 4.0 3.9 4.0

18.2 16.4 12.5 8.5 8.2

11.8 10.0 9.0 8.8 9.0

11.1 9.0 8.4 7.8 7.8

Chemical composition (% dry Ether

extract

2.3 1.6 1.3 1.2 0.8

2.3 2.5 1.9 1.2 1.4

3.0 2.7 3.2 3.5 3.5

2.4 9.2 2.5 2.7 2.7

Crude fibre

30.8 30.2 31.3 32.7 36.0

25.5 25.5 27.3 29.2 29.0

19.0 20.0 12.0 11.3 9.8

27.4 25.0 19.1 . 18.4 17.8

Ash

5.2 4.7 5.0 5.2 6.0

11.0 12.0 12.0 12.8 13.1

4.0 3.0 1.5 1.2 1.2

6.8 5.4 4.0 3.9 3.8

matter) N-free extract

54.7 59.5 58.4 57.0 53.2

43.0 43.6 46.3 48.3 48.3

62.2 64.3 74.3 75.2 76.5

52.3 58.4 66.0 67.2 67.9

Reducing sugars

16.3 15.0 13.8 4.0 2.8

4.0 5.0 3.2 2.8 2.0

25.0 11.0 4.7 2.5 2.0

13.9 11.3 6.6 2.8 2.2

323 In the whole plant and therefore in the fodder, the greatest

modifications concern the increase in N-free extract and the reduction in sugars and fibre. The maximum rate of reduction in sugars occurred around the dough stage or just after, when root absorption ceased in the almost physiologically ripe plant, and the food reserves were transferred to the grain. Even protein and ash showed a certain decrease but this was much smaller, whereas the ether-extract remained almost constant.

EFFECTS ON FORAGE CONSERVATION

In order to answer this question the experiments carried out during the last ten years at the "Centro Conservazione Foraggi" were elaborated. In total, there were 24 trials with about 500 samples for maize silage and 22 experiments with about 200 samples for high-moisture grain and ear.

The results given in Figure 4 show a close correlation between fodder DM content and the storage process in the silo.

With a delay in harvesting and therefore with the increase in fodder DM, the DM storage losses and the maize silage acid content diminished linearly.

In particular, in our experiments, these decreases were 0.35, 0.25 and 0.10 points, respectively, for DM losses and for lactic and acetic acid contents for each 1% increase in DM at ensiling. The pH increased by 0.0136, whereas no significant variation was obtained for NH3.

With high-moisture grain and ear the decreases in lactic and acetic acids were 0.13 and 0.05, whereas for DM ahd ammonia nitrogen losses no significant correlation was recorded between losses and the content of moisture in the ensiled material.

The intensity of the fermentation process for maize silage depends mainly on the sugar content even if, at the more advanced stages of ripening, the ratio of acids to sugars tends to be higher, i.e. the relative quantity of fermented sugars is higher. This trend would appear to have its explanation in the lower pH value, for early harvested maize silage, which acts as a limiting factor on bacterial activity.

In the high moisture grain, where the sugar content practically does not vary according to grain moisture, it would

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CONCLUSIONS

All the results from these trials tend to demonstrate that plant growth rate, yield and forage qualitative characteristics vary with water availability and sometimes with hybrid earliness.

Maximum DM yield is reached 45-50 days after flowering with a forage DM content that ranges from 42% to 38% for irrigated and unirrigated land respectively. Under these latter con­ditions, the same DM content variation (from 42% to 38%) is observed between early and late hybrids but with a delay of about a week for the former one (the productive peak is reached 52-57 days after flowering).

These trends are mainly due to the variation in the plant component ratios, of which the grain plays the most important role, rather than to DM content in the separate plant components.

These results, together with the forage chemical composition and storage losses, tend to indicate the advantages of harvesting at the maximum crop yield stage, i.e. after the dough stage. However, this does not appear to be advisable for maize silage because of the inevitable qualitative deterioration due to stalk fibre lignification and to the greater amount of undigested grain. In order to give a final judgement on this argument it is necessary to evaluate the real nutritive value of maize silage harvested in various maturity stages in feeding trials.

REFERENCES

Andrieu, M., 1970. Valeur alimentaire du mais-fourrage. Journées d'Inform­ation sur le mais plant fourragère, Paris, 27-28 Janvier.

Caldwell, D.M. and Perry, T.W., 1971. Relationship between stage of maturity of the corn plant at time of harvest for corn silage and chemical com­position. Journal of Dairy Science, 4, 533-536.

Cántele, A. and Giardini, L., 1966. Variazioni qualitative e quantitative indotte dalla mancata fecondazione nelle pianta di mais. Zootecnica Agricoltura, Veterinaria, 10, 309-326.

326

Cummins, D.G., 1970. Quality and yield of corn plants and components when harvested for silage at different maturity stages. Agronomy Journal, 6, 781­784.

Emberger, L., 1933. Revue Générale de Botanique, 45, 473­486. Geasler, M., Henderson, Η.E. and Hawkins, D.R., 1967. Effect of stage of

maturity and fineness of chop on yield per acre and feeding value of corn silage. Michigan State University, Report, AH­BC­666.

Giardini, Α., 1969. L'erbaio di mais in coltura rada e fitta. L'aliment­

azione Animale, 3, 121­136. Giardini, A. and Toderi, G., 1964. L'Epoca di raccolta dei foraggi per

insilamento in torre. Progresso Agricolo, 2, 171­189. Gordon, C.H., Derbyshire, J.C. and Van Soest, P.J., 1968. Normal and late

harvesting of corn for silage. Journal of Dairy Science, Ş1, 1258. Johnson, R.R., McClure, K.E., Johnson, L.J., Klosterman, E.W. and Triplett,

G.B., 1966. Corn plant maturity. I. Changes in dry matter and pro­tein distribution in corn plants. Agronomy Journal, 2, 151­153.

Mancini, E., 1940. I problemi tecnici dell'irrigazione dei terreni di piano dell'Emilia e Romagna. Atti del II Convegno Nazionale delle Irrigazioni, Bologna, 25­26 maggio.

Nelson, L.V. , Hildebrand, S.C., Henderson, Η.E., Hillman, D., Höglund, CR., Maddox, R.L. and White, R.G., 1969. Corn silage. Production, harvest, storage in Michigan. Cooperative Extension Service.

Owens, M.J., Jorgensen, N.A., Mohanty, G.P. and Voelker, H.H., 1967. Feeding value of high dry matter corn silage. Journal of Dairy Science, 50, 983.

Perry, T.W., Caldwell, D.M., Reedal, J.R. and Knodt, C.B., 1968. Stage of maturity of corn at time of harvest for silage and yield of digestible nutrients. Journal of Dairy Science, 51, 799­802.

Pollacsek, M.M. and Caenen, T.G., 1970. Journées d'Information sur le maïs plant fourragère, Paris, 27­28 Janvier.

Animal Feed Science and Technology. 1(1976) 327-343 327 Elsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands

DISCUSSION ON SESSION 3

E. Zimmer West Germany

The two papers that we are now going to discuss showed the effects of the main factors on, first , the type of fermentation and then on the amount of losses and reduction in energy content - that means the change in nutritive value. This was done in the papers both for whole-crop silage and for high moisture ear corn or high moisture grain. These factors are mainly the stage of maturity or the DM content of the maize plant or ears or grain. Then physical treatment affects particle size and aeration during the filling procedure, during the storage period or during unloading. Physical treatment and aeration means silage technology. From that we are able to estimate what we call unavoidable losses, or the unavoidable changes during fermentation, the minimum biological losses and changes and also as the second paper also showed, the avoidable losses and changes which will sometimes double or even triple the former figure. So, if we follow this general line, we may discuss first, whole crop maize and second the conservation of ears or high moisture grain.

J.B. Kilkenny UK

I ask for further information on the heating process. Firstly, I am interested in the comment in Dr. Zimmer's paper on the effect of urea reducing losses through heating. I would like more information on the chemistry of that reaction. Secondly, I would like some recommendations on what rate of feeding we should be recommending to farmers for silage. In other words, how quickly should farmers be utilising maize silage, in the summer in particular, to reduce these problems of heating?

E. Zimmer

Firstly, heating or so-called 'after-fermentation'. It is not fermentation but a complete mineralisation of organic acids

328 and therefore there is an increase in pH, decrease in acids, and following that, other processes of decomposition. From our knowledge up to now, yeasts are more or less responsible. However, in the last few days, we finished discussion with Dr. Woolford from Hurley who studied at our Institute for six months with Dr. Hönig, the question whether bacteria are also involved in the heating process and we have some data which goes in this direction. However, we need to deal a little more with this problem. The effect of urea we can explain up to now only by stating that urea often gives a more hetero-lactic type of fermentation which means more acetic acid. We know that acetic as well as propionic and butyric has a fungicidal effect. This is our explanation; we did not look more deeply into the details. It was noted in experiments in the Institute as well as in France.

Now the recommendation to farmers is, first of all, to have the right size of silo for the number of animals in the group; the right size of trench or the right size of tower. Then they must ensure quick filling, very good packing and very quick covering of the silo because aeration at the beginning of fermentation causes the risk of heating after storage. These are the old recipes we can give, or they can add some organic acid, but this depends on cost.

H. Hönig West Gerrxv.y

I would like to make some additions to the chemistry of the effect of urea or ammonia in preventing aerobic decomposition when unloading the silo: we found that the effect of Prosil as an ammonia additive was better than that of urea and this indicates that the specific effect of ammonia against those micro-organisms responsible for aerobic deterioration is active at the beginning of the fermentation process at the time of ensiling. The normal lactic fermentation proceeds in ammonia-treated silage but it takes three or four days after opening the silo for the responsible micro-organisms to develop anew. Urea is transformed to ammonia and so its effect cannot be as high as a pure ammonia additive. That is what we found out from these results. For the prevention of aerobic

329

decomposition when unloading the silo, I would want to point out once more the very great effect of good or bad technology. We made comparisons of unloading the silo by rapid tearing out of the material with the front-end unloader, and cutting exact blocks or scraping the silo face with the unloader, and we had a marked difference in the aerobic deterioration. It started in the first case, after the second day and in the other case after three or four days only, and that is enough time for the farmer to use the stable silage. Another finding was that when blocks cut by block-cutting device were put in the feeding area of the cattle-shed they were stable for 7 days. Beside these we put the same material loosened and it heated up after 3 days. This is another hint that keeping the compactness is very, very important to prevent aerobic deterioration.

R.J. Wilkins UK

I would like to support Dr. Hönig strongly in his statement on the key ways of preventing aerobic deterioration. We, like Professor Zimmer, have been involved in some studies of chemical means of control of this process of deterioration but our feeling at the moment is that in most feeding situations it is a matter of management of the ensiling and silage feeding in such a way as to minimise the exposure of the mass to air. We have done some limited experimentation on the effects of non-protein nitrogen additives. In one experiment we found that Prosil, in comparison with propionic acid, did increase aerobic stability. Heating up was delayed by perhaps a day or two more than that of untreated silage but the effect was less than we had obtained with an addition of 0.25% propionic acid on a fresh matter basis. So the results we had are in the same direction as those obtained in Michigan and in Braunschweig and we associated this effect with the lower total viable count of micro-organisms of the Prosil-treated material when it was taken out of the silo, compared with the silage made without additives. In further experiments with propionic acid , our findings would be very similar to those in Germany. To give you a long term stability in aerobic conditions application rates of at least 0.5% propionic acid on a DM basis are needed.

330

This would give you tremendous flexibility in feeding out but it is an expensive procedure. With urea we have no experiments but our observations would not support the finding of an increase in aerobic stability in urea-treated maize silage. This is only a very limited observation.

E. Zimmer

What I was pointing out is that NPN as an additive to add nitrogen has another interesting effect from the standpoint of fermentation and therefore we looked into this stabilising effect against heating. So, we can recommend to farmers that if they add NPN they will have, in addition, this stabilising effect against heating because we know, as Dr. Wilkins said, also under German conditions, adding 0.5% or even 0.7% of propionic acid or acetic is not economic. So we cannot recommend using propionic acid at present. Do we have any other comments on this heating problem or other questions?

R.L. Vetter USA

I have one comment arising from your paper - you are discounting the high penalties of lactic acid fermentation. I believe from our work that lactic acid has a higher energetic efficiency than any other of the dry matter components. When you add urea or Prosil, there is the initial phase which you explained very well and then there is a buffering effect which allows the production of a greater total amount of acids. My question is, are you recommending a procedure which you are saying is reducing the amount of acid production? I wonder if you are not really getting more total acids, If you look at lactic acid as having a higher energetic efficiency, even though you have a slight DM loss, the net efficiency to the animal may be equal to or greater than when you have less lactic acid production.

E. Zimmer

We did not look at this higher energy efficiency; we know

331

by using urea, buffering capacity is increased and therefore we get higher lactic acid content. If you calculate this on an energy loss basis this increase, let me say, of 2 or 4 points on a DM basis compared with a 3.5% energy loss converting sugar to lactic acid means it is within the range of our methods. So, we do not recommend a certain method to increase buffering capacity, under German conditions, as the people from Ohio stated in the early 1950s, but we know the effect of using NPN and therefore we say that this is the effect on fermentation. We did not go into feeding experiments and I am not sure whether this small difference will have an effect on the animals - maybe Professor Kaufmann can give an answer. It is only 4%.

W. Kaufmann West Germany

I would agree with Zimmer; I would not believe that you would find any difference in energy efficiency with a little more lactic acid.

E. Zimmer

I think it is 4% - we go from 10 - 14% or 8 - 12%. This is compared to the whole net energy content; it is a very small change in the composition of carbohydrates. I have not found any new experimental data from the States going the way the Ohio people did in the middle 1950s. Can you give new data Professor Vetter?

R.L. Vetter

Dr. Owens from Oklahoma recently reported on net efficiency although I do not know the data in detail. We are talking here of the conversion of organic matter in the fermentation of silage but that loss versus the loss in the rumen where you have methanogenesis so that you are absorbing lactate.

K.G. Møl le Denmark

A few years ago some firms advised that if you were unlucky

332

and the silage was heating during unloading you could treat it with, for instance, propionic acid, the moment you were aware of the heating. Now, in your paper Professor Zimmer, I find it stated that application to prevent heating has to be done during filling. Does that mean, in other words, that it is not worthwhile for a farmer if his silage is heating, to apply acid in order to try to arrest that heating because some people still think that there is a possibility to do so?

E. Zimmer

This was a wrong recommendation, that is our answer, because if a certain yeast population, or even bacterial population, was built up five months ago then you cannot penetrate enough propionic acid into your trench silo or tower silo to kill them. It is technically impossible. You can penetrate maybe 2 cm, for example.

J.M. Wilkinson UK

My question refers to your Figure 3, Professor Zimmer, where you show the difference in starch equivalent between silage and fresh maize in relation to DM content. Now I can understand the decrease in starch equivalent as a result of fermentation and the loss of the most digestible parts of the plant, the starch content, but I am a bit puzzled as to why the difference between silage and fresh material should get greater, in absolute terms, as DM content increases, because one would expect the extent of fermentation to decrease. Is it because of increased respiration or aerobic deterioration, or what factor?

E. Zimmer

No, I would say that it is because of the mathematical model I had to use to bring together all the available data. Like you, I was astonished by this smaller difference but I could not find another correlation and regression formula for both the data coming from fresh material and other material. So, these data will give only the general tendency here and you

333 cannot take them and say that for 20% DM content, then it is 22.5 starch equivalent difference, and going to another DM content it is exactly the same; it is general tendency. We do not have sufficient experiments comparing those things over the whole period of DM content, of stages of maturity.

W. Kaufmann

There might be a difference between the calculation of starch equivalents and other calculations of energy content, because in starch equivalents there is a calculation from the crude fibre.

E. Zimmer

However, this cannot account for this difference that Dr. Wilkinson has stated.

C. Lelong France

I would agree with your conclusions on the effect of propionic acid during summer when you cut a slice of silage. We try to avoid formation of yeast under the plastic cover and we apply a little propionic acid on the surface there and we find the yeast is decreased to a depth of 10 or 15 cm.

E. Zimmer

This is another picture, of course. As I stated, and Dr. Hönig and Dr. Wilkins agreed with me, good management will prevent the risk of heating. Good management means high density, quick filling to avoid aeration and therefore in the deeper layers of your silo also you can prevent it by its own density, by the covering of the deeper layers by the higher layers. Then you have a special risk to the last layer of the silo and if you add some propionic acid here then you get an additional precaution. There we would agree, However, the question was related to adding propionic acid during unloading when heating had already started and at this stage it is

334 impossible to do it.

C. Lelong

I have another question, to Parigi-Bini, on ear conservation. You had a very low DM content. I agree with you and our conclusion is that it is necessary to ensile ears with only 55 - 60% DM but at 75% of DM it is possible to put cobs in cribs and it is well-known that minimum water content is necessary to get good fermentation.

R. Parigi-Bini Italy

No, I said that when the DM goes higher than 65%, fermentation declines very rapidly.

E. Zimmer

This is a general tendency that with increasing DM in any kind of crops we have to ensile, we decrease the activity of our micro-organisms and stabilise fermentation in terms of the proportion of lactic acid to volatile fatty acids. Then, of course, we increase pH, but pH and dry matter content are closely correlated. It is not inevitable that more yeast develops with a higher DM content, if the management is good.

C. Lelong

The production of ear silage is very difficult beyond 65% DM.

R. Parigi-Bini

However, in several years, in some weather conditions in Italy, we have been obliged to collect ears at more than 70% DM. The dry matter of our crop is going up, more than 1% in the entire plant per day in the particular weather conditions, when we have sun and also wind^and the dry matter goes very high in just two or three days. This is why in my conclusion I say, 'when not imposed by climatic conditions'. In the real conditions

335

of the farm you do not have time to collect more quickly. In a few days, in our conditions in Italy, the DM in the crop goes up very rapidly.

E. Ζ immer

This question from Mr. Lelong changed to the second paper. May I ask you to finish the discussion on the first paper if there are any other questions.

D. Lanari Italy

I would like to ask you a question. Professor Zimmer, relating to your Table 3, 'Effect of Chopping Treatment on Maize'. I am interested in the figures you report of the percentage of DM in faeces. Did you measure the overall digest­ibility or just measure the amount of DM that you collected by washing faeces and looking at the grain content?

H. Httnig

Grain losses in the faeces are determined as follows: we freeze­dry a sample of faeces, then sort out the grains and calculate the amount of dry matter weight of grains in relation to the dry matter weight of grain in the feed. In addition we have analysed the material of the grains sorted out from the faeces and found that they were practically of the same value as the grains going into the rumen.

The relationship between the whole grain eaten and the grain not digested was about 20% for high dry matter maize and only 10% for material harvested at an earlier stage with a dry matter content of 25 ­ 30%.

D. Lanari

Did you run digestion trials?

336 H. Hönig

We did not.

Lanari

I am thinking that probably you do not find such a big difference in organic matter digestibility between maize silage which is reçut and that which is not reçut after unloading.

E. Zimmer

Because of some digestion of the kernels?

D. Lanari

Because, probably, there is the same kind of losses, there is no advantage in recutting after unloading.

F. de Boer Netherlands

I have a question on one detail of your statement in your paper on NPN additives. You mention that, in Germany, urea and the combination of minerals with urea is in common use. Now, I am curious to know how many ha of your maize silage are made with this 'Maisfertil' because in our conditions which are more or less comparable, it is only about 1% of all silage which is made with this urea/mineral mixture. When you say 'in common use' do you mean IO, 20, 30% of your silage is made in this way?

No, not such big amounts. Common use means well-known and used, but I cannot give a figure for 'Maisfertil' because it is a fairly new product. All the farmers know it very well, they know the advantages and disadvantages but I cannot give a percentage of the total acreage.

337

D. O o s t e n d o r p Netherlands

Can you say a little more about the way in which these products are added to the silage? What type of applicators are used?

E. Zimmer

There are applicators which are used for adding other silage additives mounted on the forage chopper. It is applied during the chopping of the material. For the liquid Prosil we do not have a really good method of application. This is still under experimentation and is a real problem. However, for urea or 'Maisfertil' it is not a technical problem, you can buy the machine.

H. Schneeberger Switzerland

I would like to come back to the question of the grain in the faeces. Has somebody more information of differences existing between sheep and cattle or between beef cattle and dairy cattle? We found in the same silage given to beef cattle and to cows that the percentage of grain in cow faeces waá much higher than in beef cattle.

W. Kaufmann

I think there are probably some papers where you can get the answer but it is probably related to the higher rate of intake. Normally beef cattle have a lower intake.

E. Zimmer

Even if you base your data on the same intake you have a different relationship for sheep and for cattle?

W. Kaufmann

That is quite another question, yes. It is about 4%, 3%

33«

difference between sheep and cattle, lower in sheep.

R.J. Wilkins

One of the points in your paper that has not been discussed yet is the question of freezing and its subsequant effects on composition and silage quality in that you have drawn attention to work where you have had both humid and dry conditions after freezing and draw a conclusion that substantial losses occur in DM and in digestibility or nutritive value. In Britain, it has been very common to ensile material weeks after freezing . In some situations we have perhaps welcomed frost as an agent for increasing somewhat the DM in the material. I am not aware of experiments in England that have looked critically at effects on composition but in two animal feeding experiments that I have undertaken myself, both involved in feeding sheep on silage which has been made from maize after different stages of development, and we have had perhaps one cut before frost and then two cuts afterwards, we have not found any major differences in fermentation in the silo. The later material harvested at a rather higher DM content had rather less fermentation, and we have not found major differences in intake or digestibility. I would like your further comments, or other people's comments, on this. I would agree, certainly, that if you have got a crop that is frosted you are more liable to be losing material physically during the harvesting operation and that your recovered DM yields are likely to be reduced.

E. Zimmer

There is very little information on this. If you look in the paper you will find only three or four publications. We do not have experiments of our own dealing with this question but we feel that we have to do it in the near future to look more precisely at the things going on. However, from looking into the farm situation it seems to us that a higher amount of poor fermentation, which is uncommon for maize because normally you have only good fermentation quality, is found after harvesting the maize late in autumn, after freezing. There are

339

a few observations that the epiphytic flora will change so that there are more proteolytic bacteria, more coli, and so on. So this, together, gives a picture of a certain degree of risk but nobody can give a certain answer and I could not find more details. We have to look at these particular conditions, because, in the northern parts of Europe, they are normal.

C. Lelong

Andrieu has some information on the sugar content of normal plants and frosted plants. In normal plants the sugar content is about 18% at the milk stage. Three weeks after frost the average content was 5.9 - 6% of sugar. Five weeks after freezing it was only 2% of sugar. This will be an explanation of your prediction.

R.H. Phipps UK

We have also noted that the mineral composition of the crop after freezing (I assume you mean a hard frost) has decreased markedly and also, obviously, the vitamin A content of the crop would be decreased considerably. We have got some inform­ation indicating a decrease in the digestibility of the crop after frosting.

E. Zimmer

We must now discuss the second paper, dealing with the ensiling of high moisture ears and high moisture grain. One aspect has already been discussed. Are there any questions or comments? From our own experiments, reported in Paris in 1973, we are in total agreement with Parigi-Bini's findings, the general tendency of increasing DM and all the other aspects.

R. Parigi-Bini

After sending in the paper for this Conference, I read in a recent number of the Journal of Animal Science, the paper of an Oklahoma State University worker which was quite

340 interesting. It was concerning the physical form of high moisture corn. They measured fermentation in the high moisture corn, ground or entire kernels, and found that fermentation was increased and the degradation of nitrogen components of the grain was more intensive in the ground form than in kernels.

E. Zimmer

I think this fits into the general picture that disintegration of cells will increase the microbial activity because there is more substrate immediately available.

C. Lelong

In France we have seen dry matter losses in big silos on farms which are,for whole plant silage, 15%; for ear silage about 8%; and for grain, high moisture and ground grain, about 4 - 5%.

R. Parigi-Bini

What is the DM content of your ear silage?

C. Lelong

It is 55 - 80%, and for grain, about 30 - 35% because below this moisture content it is quite impossible to manage the silo during summer because fermentation increases quickly during summer when there is a low content of water.

R. Parigi-Bini

Concerning ensiling losses I think the best measure of the losses must be made in big silos. I think the buried bag technique is not so exact especially with a product having a high DM content because you can have a good idea with a good crop silage or also with very high moisture corn or ears because there is more fermentation and also you can measure the losses.

341

Β.G. Cottyn Belgium

May I ask Dr. Parigi-Bini for some more details about the technique of buried bags to determine the percentage losses?

R. Parigi-Bini

It is just a digestibility trial inside the silo. You put a weighed quantity of material in a plastic bag but you do not seal it.

E. Zimmer

In a net.

R. Parigi-Bini

You put several kg of fresh material when you make the silo and when you open the silo you take the bag out.

B.G. Cottyn

Have you made comparisons with the classical technique of weighing in and out to determine losses?

R. Parigi-Bini

No. I measure losses just by the buried bag technique; I have no personal experience of comparisons of the two but in my opinion when using materials of high DM content it is better to weigh the whole quantity.

E. Zimmer

If you want to look in more detail at the conditions of a particular region of the silo this buried bag method is a very good one. If you have enough samples with the buried bag method there should not be a difference between the total input/output balance and the buried bag input/output balance.

342 R.L. Vetter

I should try to clarify some of the Oklahoma work, In the USA much of our high moisture grain is put into vertical silos and in looking at that type of storage versus the trench or bunker silo (which I am sure you are using more) the data favour consistently, in many trials, storage in whole grain form and then rolling the grain prior to feeding but with maize moisture in the range of 22 - 30% the process is basically one, in the initial phases, of germination preceding fermentation. Most of the data pooled from the trials show a consistent performance advantage to storage as Whole grain, provided that it is in an upright silo with a good structure. In a horizontal structure compaction is necessary, by rolling or crushing the grain before it is ensiled. With high moisture grain or reconstituting grain like milo, particularly, there is an improvement by reconstituting to a high moisture level in the whole form and then rolling before feeding. This aspect should be distinguished here because the data in the USA are very consistent with that type of processing.

C. Lelong

What is the effect of conservation time on losses?

R. Parigi-Bini

These experiments have been conducted in a fixed time.

C. Lelong

I thought whole plant silage gave this information.

E. Zimmer

From measuring C0„ production over a long period we know that if we have stable conditions, CO., production is near zero. If we have some leakage we have an increase, and under sub-

343

optimal conditions, or farm conditions, we have an increase and this is then 1% DM or even 2% DM per month. This seems to us a general rule for all the crops we have.

345

SESSION IV

NUTRITIVE VALUE FOR BEEF CATTLE OF DIETS BASED ON THE MAIZE CROP

Nutritive value of different forms of the maize crop: voluntary intake; digestibility; utilisation of nutrients; rate of growth of cattle; efficiency of feed conversion,· metabolic disorders. Effects of type of conservation and processing; pattern of fermentation; additives; supplements of energy, protein, NPN and alkali.

a) Effects of type of diet on energy intake and growth rate Chairman: T. Cobic

b) Nitrogen metabolism and research techniques Chairman: W. Kaufmann

c) Utilisation of dietary energy Chairman: W. Kaufmann

Animal Feed Science and Technology. 1 (1976) 347­367 3 4 7 Elsevier Sdentine Publishing Company, Amsterdam ­ Printed in The Netherlands

MAIZE SILAGE WITH OR WITHOUT NPN, DEHYDRATED WHOLE­CROP' MAIZE PELLETS OR HIGH MOISTURE MAIZE GRAIN FOR FINISHING BULLS*

Ch. V. BOUCQUE, B.G. COTTYN and F.X. BUYSSE National Institute for Animal Nutrition, Β 9231 Gontrode, Belgium.

ABSTRACT

The chemical composition, digestibility and feeding value of 11 lots of maize silage, 11 lots of dehydrated whole­crop maize pellets and 4 batches of high moisture corn have been studied. Digestibility (determined with wethers) and net energy were generally higher for the maize silages than for the dehydrated pellets.

Beef production experiments were carried out over 3 consec­utive years with 170 young bulls, to study the influence of method of conservation and the height of cutting on animal performance and on the output of beef per ha. Five basic feed­stuffs were given ad libitum: silage from maize cut at 15 cm and at 35 cm above ground level, pellets of dehydrated whole­crop maize which was cut at 13 cm and at 40 cm above ground level, and high moisture maize grain treated with propionic acid. Each group was supplemented with the same protein rich concentrate (19% DCP) at 1% of liveweight. The daily liveweight gain was significantly higher (1431 g/day) for the animals receiving high moisture grain than for those fed with maize silage or maize pellets. The utilisation of the dry matter of the maize silages was more efficient than of the dehydrated maize pellets. The dressing percent and the feed cost price were also in favour of the maize silage rations.

The highest beef output per ha of maize was obtained with the silage and the pelleted maize harvested at the lowest height of cutting.

A second beef production experiment was carried out with 83 young bulls over 2 years to study the effect of NPN addition to maize just prior 'to ensiling. From the preliminary results it can be concluded that the addition of 0.5% urea (Rumipec) or * Communication no.355 of the Institute

348 1.9 to 2.4% Pro-Sil (16.6% NH3) to the silage or plant protein in the concentrate resulted in a significant increase in daily gain and dressing percent compared with the negative control. No difference could be observed between the urea, the NH3 treatment and the positive control for the entire fattening period.

INTRODUCTION

Maize can mainly be used in 3 different forms as a basic feed for beef cattle: silage, dehydrated whole-crop maize pellets and high moisture grain. This paper reports:

a) trials with sheep to determine the digestibility of maize silage, dehydrated whole-crop maize pellets and high-moisture maize. b) beef production trials in which the 3 different forms of the maize crop were fed åd libitum as the basic feed to young bulls. For the silage and for the pellets, the maize plants were cut at 2 different heights above ground level (15 cm and 35-40 cm). For the different systems of harvesting and storing, animal performance was studied and the output of beef per ha was calculated. c) beef production trials with young bulls to study the utilisation of NPN sources in maize silage (provisional results; experiments still in progress).

CHEMICAL COMPOSITION, DIGESTIBILITY AND FEEDING VALUE OF MAIZE SILAGE, DEHYDRATED WHOLE-CROP MAIZE PELLETS AND ROLLED HIGH MOISTURE MAIZE

The digestibility of the different feeds of the maize crop given to fattening bulls during the last 10 years, has been determined with sheep.

The digestion trials were always carried out with 4 wethers fed at the maintenance level; faeces were quantitatively collected and sampled twice a day during a 10-day period.

In total, 11 lots of maize silage, 11 lots of dehydrated maize pellets and 4 lots of rolled high moisture grain have

349

been studied. The maize for silage (Anjou 210) was grown at the Institute and harvested at different stages of maturity varying from the early milk stage (1972) to the dough dent stage. In 1970, 1971 and 1972 two different heights of cutting were applied: 15 cm and 35 cm above ground level. The maize was finely chopped and preserved in trench silos without additives. The dehydrated whole­crop maize pellets were purch­ased from different commercial drying plants (10 lots from Belgium and 1 from France). The 4 lots of high moisture grain were purchased at a large crop farm, treated with 1.2 to 2.0% propionic acid and stored as whole grain in open concrete silos until the end of the beef production trials. The added percent­age of propionic acid varied depending on the moisture content of the grain and the time of storage; the grain was rolled prior to feeding.

The chemical composition, the digestion coefficients and the net energy content of the maize silages, the maize pellets and the high moisture grain are presented in Tables 1, 2 and 3. The starch equivalent was calculated by the method of Kellner and Becker (1971); for the maize pellets a deduction factor of 0.44 per percent crude fibre was applied. The maize silages and the pellets are classified on the basis of their crude fibre content.

The 11 maize silages were characterised by a large diversity in dry matter content (17.6 to 28.2%), in crude fibre content (16.3 to 26.7% in the DM) and in the N­free extract content (48.5 to 63.5% in the DM). For these silages, harvested in different years, significant relationships (P <0.0l) could be calculated between the crude fibre content and the digest­ibility of the organic matter (r = ­0.78**) or the digestibility of the N­free extract fraction (r = ­0.89**). Demarquilly (1969), Andrieu and Demarquilly (1971) and Aerts et al. (1976) Obtained a nearly constant digestibility for maize harvested between the milk stage and the mature stage (24 to 30% dry matter).

The net energy content of the silages (y = starch equivalent) was negatively related to the crude fibre content (x): y =­1.17x + 87.68; r = ­0.90**; Ρ <0.01.

For the 11 lots of dehydrated whole­crop maize pellets no significant relation could be established between the

TABLE 1 CHEMICAL COMPOSITION, DIGESTIBILITY AND FEEDING VALUE OF MAIZE SILAGE

Year of har­vest

1972b ! 1972a { 1974 1973 1973 1971 1971a 1974 1970a 1971b 1970b

flean

Í SD

Dry mat­ter (%)

17.6 19.4 22.5 23.2 26.5 22.1 24.4 27.4 25.1 26.3 28.2

23.9

3.3

Composition of

Organic matter

92.2 91.8 93.2 93.0 93.1 93.7 92.9 93.8 93.7 93.9 94.0

93.2

0.7

Crude protein

11.1 10.7 8.8 9.2 9.6 8.6 9.0 8.6 9.2 9.4 8.8

9.4

0.8

the dry matter (%)

Crude fibre

26.7 26.6 22.7 21.5 21.3 20.8 20.5 18.5 18.3 17.5 16.3

21.0

3.4

Ether extr.

4.7 5.9 3.4 4.5 4.7 4.6 4.4 3.5 6.8 3.5 6.9

4.8

1.2

N-free extr.

49.7 48.5 58.3 57.8 57.5 59.7 59.0 63.2 59.4 63.5 62.0

58.0

4.9

Dry matter

61.0 62.4 69.7 70.4 67.0 64.9 70.3 69.9 71.0 69.0 70.9

67.9

3.6

Digestion coefficients

Organic matter

64.6 66.0 73.1 73.7 69.9 68.6 73.7 72.7 74.0 71.8 73.6

71.1

3.3

Crude protein

55.7 54.3 58.7 63.1 58.2 35.4 58.3 58.7 61.2 59.3 53.3

56.0 ·

7.4

Crude fibre

68.2 67.3 68.7 68.5 61.9 60.6 66.9 63.5 63.3 56.5 57.5

63.9

4.4

(%)

Ether extr.

77.6 84.7 75.2 82.5 81.2 81.0 83.0 81.5 88.3 79.6 88.0

82.1

4.0

N-free extr.

66.1 65.5 76.9 76.7 73.9 75.2 77.8 76.8 77.6 77.4 79.1

74.8

4.7

Starch equivalent

(% DM)

55.6 56.5 63.1 64.9 61.6 61.0 65.4 64.7 68.8 64.5 69.5

63.2

4.4

a = Maize harvested at 15 cm above ground level; b = 35 cm

TABLE 2 CHEMICAL COMPOSITION, DIGESTIBILITY AND FEEDING VALUE OF DEHYDRATED WHOLE­CROP MAIZE PELLETS

Year of har­

vest

1967 l?72b 1972a 1968 1970b 1971 1971b 1970a 1971a 1969 1971

Mean

+ ,­ SD

Dry mat­

ter (%)

88.0 84.8 88.2 90.5 88.6 91.8 86.1 90.6 91.6 88.9 89.7

89.0

2.2

Compo

Organic matter

88.1 05.1 95.3 94.8 95.3 95.4 94.3 94.4 96.4 95.3 95.2

94.5

2.2

sition of

Crude protein

14.6 8.0 8.5 8.7 8.1 7.7 7.5 8.4 8.0 8.9 9.1

8.9

1.9

the dry

■Crude fibre

21.8 20.6 19.2 17.7 17.1 16.7 16.7 16.5 14.7 14.3 14.1

17.2

2.5

matter

Ether extr.

4.4 3.3 2.9 3.5 2.6 3.1 3.2 3.1 3.2 3.6 3.0

3.3

0.5

(%)

N­free extr.

47.3 62.3 64.7 64.9 67.5 67.9 66.9 66.4 70.5 68.5 68.9

05.1

6.3

Dry matter

61.8 66.1 70.4 61.4 61.0 62.8 65.7 66.9 69.8 69.9 70.3

66.0

3.8

Digestion coefficients

Organic matter

64.6 67.8 71.9 63.4 63.4 64.6 68.7 69.4 71.2 72.9 72.4

68.2

3.7

Crude protein

59.9 39.4 44.5 48.3 38.2 28.9 49.8 52.2 50.7 59.8 58.7

48.2

9.8

Crude fibre

57.0 58.6 61.7 37.0 40.2 38.7 51.2 48.1 46.0 46.9 49.8

48.7

8.1

Ui­

Ether extr.

69.1 76.1 66.6 77.7 71.9 67.3 70.7 75.0 76.0 84.5 82.5

74.3

5.9

N­free extr.

69.0 74.4 79.3 71.8 72.0 74.8 75.7 76.6 78.6 79.5 78.4

75.5

3.5

Starch equi­

valent (% DM)

49.6 57.4 61.9 54.6 54.5 56.0 59.7 60.1 64.2 65.7 64.6

58.9

5.0

a = Maize harvested at 15 cm above ground level; b = 35 cm

TABLE 3 CHEMICAL COMPOSITION, DIGESTIBILITY AND FEEDING VALUE OF ROLLED HIGH MOISTURE GRAIN

Year of har­vest

1970 1971 1973 1974

Mean

+ - SD

Dry mat­ter U)

66.3 65.3 62.0 64.3

64.5

1.8

Compo

Organic matter

98.0 98.3 98.2 97.6

98.0

0.3

sition of

Crude protein

10.8 9.7 9.1 10.5

10.0

0.8

the dry

Crude fibre

1.9 1.9 2.4 2.0

2.0

0.2

matter

Ether extr.

5.0 3.9 3.7 2.9

3.9

0.9

(*)

N-free extr.

80.3 82.8 83.0 82.2

82.1

1.2

Digestion coefficients (%)

Dry matter

90.6 87.7 89.7 91.4

89.9

1.6

Organic matter

90.9 88.6 90.5 93.1

90.8

3.4

Crude protein

74.6 60.5 65.8 70.8

67.9

6.1

Crude Ether fibre extr.

83.8 78.1

33.2 85.5 88.8

84.1

4.5

N-free extr.

94.3 93.9 95.2 96.5

95.0

1.2

Starch equi­valent (% DM)

95.9 92.4 95.0 93.9

94.3

2.3

353 crude fibre content and the digestibility of the organic matter. The digestibility of the N-free extract fraction (y) was negatively correlated with the crude fibre content (x): y = -0.91x + 91.07; r = -0.65*; P<0.05. The gradual decrease of the crude fibre content (x) resulted in a significant increase in the starch equivalent (y): y = -1.51x + 84.95; r = -0.75**; P<0.01. Earlier digestibility trials with maize pellets were already published by Cottyn (1969) and Cottyn et al. (1973).

When the maize silages are compared with the dehydrated maize pellets, the digestibility of the organic matter and the starch equivalent content are generally lower for the pellets than for the silages. Especially when only the 8 silages and the 8 batches of pellets are compared, having a crude fibre content with the 16.3 - 21.8% range (Tables 1, 2 and 4), the differences in digestibility coefficients and in the net energy content are more pronounced in favour of the maize silages. This is in accordance with results of Béranger and Marchadier (1970) and Demarquilly and Andrieu (1970). The highest depression occurred in the digestibility of the crude fibre fraction: the mean coefficient decreased from 62.3 (for the 8 silages) to 49.1 (for the 8 lots of pellets). Demarquilly (1971), Dijkstra et al. (1971), Malterre et al. (1971), Zgajnar (1972) and Cottyn et al. (1976) obtained similar results. The dehydration process at high temperatures has also reduced the digestibility (especially of the protein) of other crops such as grass (Knutsson et al. 1973) and lucerne (Saunders et al. 1973).

The net energy expressed in terms of starch equivalent in the dry matter is highest for the high moisture grain owing to its high content of highly digestible N-free extract fraction (Table 3). The variation in net energy content of the 4 lots of maize grain is much smaller than for the maize silages and the dehydrated maize pellets.

354

TABLE 4

COMPARISON BETWEEN MAIZE SILAGES AND DEHYDRATED WHOLE­CROP MAIZE PELLETS HAVING A CORRESPONDING CRUDE FIBRE CONTENT ( 1 6 . 3 t o 21.8«. i n t h e DM)

(Means + s t a n d a r d d e v i a t i o n )

Number of lots Dry matter Organic matter Crude protein Crude fibrr Ether extract N­free extract Starch equivalent Digestible crude protein

Chemical sition (>

Silage

8 100*

9 3.=; + 0.4 9.0 + 0.4 19.3 + 1.9 4.9 + 1.3

60.3 + 2.3 65.1 + 3.0

5.1 + 0.9

compo­

DM)

Pellets

8 100*

91.1 + 2.5 o.o + 2.3 18.3 + 2.0 3.3 + 0.5

63.5 + 6.8 56.7 + 3.9

4.2 + 1.9

Digestion coefficient ( .)

Silage Pellets

8 8 6 1 . 2 + 2 . 2 64.5 +3.3 7 2 . 3 + 2 . 0 6 6 . 7 + 3 . 2 55.9 + 8.8 45.2 + 9.6 62.3 + 4.2 49.1 + 9.6 83.1 + 3.3 71.8 + 4.1 76.8 + 1.6 74.2 + 3.2

­

­

* Mean DM c o n t e n t : 25.4« for the 8 s i l a g e s and 88.6% for t he 8 p e l l e t s

MAIZE SILAGE, DEHYDRATED WHOLE­CROP MAIZE PELLETS OR ROLLED

HIGH MOISTURE GRAIN AS BASIC FEED FOR YOUNG FATTENING BULLS

Experj j t ie inţa^l

D u r i n g t h r e e y e a r s ( 1 9 7 0 , 1 9 7 1 a n d 1972) b e e f p r o d u c t i o n

t r i a l s w e r e c a r r i e d o u t w i t h 1 7 0 b u l l s t o s t u d y t h e u t i l i s a t i o n

o f 3 d i f f e r e n t f o r m s o f t h e m a i z e c r o p : s i l a g e , d e h y d r a t e d

w h o l e ­ c r o p m a i z e p e l l e t s a n d h i g h m o i s t u r e g r a i n . F o r t h e

s i l a g e a n d f o r t h e p e l l e t s , t h e m a i z e c r o p w a s c u t a t 2

d i f f e r e n t h e i g h t s a b o v e g r o u n d l e v e l (15 cm a n d 35 c m ) . The

m a i z e f o r s i l a g e ( A n j o u 2 1 0 ) was g r o w n a t t h e I n s t i t u t e a t

G o n t r o d e a n d h a r v e s t e d a t t h e d o u g h ­ d e n t s t a g e e x c e p t i n 1972

when t h e c r o p h a r d l y r e a c h e d t h e m i l k s t a g e b e c a u s e o f t h e b a d

c l i m a t i c c o n d i t i o n s i n t h a t s u m m e r . The d e h y d r a t e d w h o l e ­ c r o p

m a i z e p e l l e t s w e r e p u r c h a s e d f r o m a c o m m e r c i a l d r y i n g p l a n t ;

t h e m a i z e was a l s o c u t a t t w o d i f f e r e n t h e i g h t s a b o v e g r o u n d

l e v e l (13 cm a n d 40 c m ) , c h o p p e d t o a maximum l e n g t h o f 2 cm,

d e h y d r a t e d , h a m m e r ­ m i l l e d a n d p e l l e t e d .

355 The high moisture grain was treated with 1.2 to 2.0%

propionic acid and preserved as whole grain in open concrete silos until the end of the feeding trials. The grain was rolled prior to feeding.

Each of the 5 basic feeds (2 silages, 2 pellets and 1 high moisture grain) was given ad libitum and supplemented with a protein rich concentrate (19% DCP) at 1% of liveweight. Straw was always available in the hay rack. The feeding value of the different feeds is shown in Table 5.

TABLE 5 MEAN FEEDING VALUE OF FEEDS (% of DRY MATTER)

Experi­mental year

1970-71

1971-72

1972-73

Height of cut

DM* DCP CF SE

DM DCP CF SE

DM DCP CF SE

Maize silage

15 cm

24.4 5.8 18.9 68.5

24.4 4.3 20.8 62.8

18.8 5.9 29.3 56.4

35 cm

26.6 5.2 16.4 68.4

25.8 5.9 18.3 62.9

18.7 5.9

27.8 57.2

Dehydrated maize pellets

13 cm 40 cm

91.2 89.6 4.4 3.1 16.6 17.4 59.8 54.0

89.3 87.8 4.4 3.0 16.3 17.3* 62.2 59.5

87.7 87.9 3.9 3.4 19.6 20.0 61.5 57.8

High moisture grain

62.5 6.5 1.1 94.6

68.2 6.5 1.6 91.8

55.9 6.1 3.0 91.6

Concen­trate

85.5 22.9 6.6 77.1

84.4 21.6 6.6 77.3

85.0 22.6 7.3 78.6

DM = dry matter content; DCP = digestible crude protein in the DM; CF = crude fibre in the DM; SE = starch equivalent in the DM

The experiments were c a r r i e d out with young s t o r e b u l l s (150 of the whi te -b lue and 20 of the whi te - red breed of Belgium), purchased a t the end of the grazing season. After a p r e -experimental per iod of 10 weeks the animals were d iv ided a t random i n t o groups of 7 t o 8 i n d i v i d u a l s ; 122 b u l l s were

356 fattened in loose houses and 48 were individually tied up; they were all bedded on straw.

Results and discussion The maize silages cut at 35 cm (Table 5) were generally

characterised by a higher dry matter, a lower crude fibre and a higher N-free extract content compared with the silages cut at 15 cm. Andrieu and Demarquilly (1971) and Cordiez et al. (1971) reported similar differences. That v/as not the case in 1972 because the maize was harvested in the milk stage. In this year the height of cutting did not influence considerably the digestibility of the organic matter and the N-free extract fraction of the silages, so the net energy values were similar. For the dehydrated maize pellets it cannot be guaranteed that the different height of cutting was applied simultaneously at the same stage of maturity; nevertheless, there was a difference in composition and in feeding value of the 6 lots of pellets.

The mean daily growth rates for the 5 rations varied between 1142 and 1431 g (Table 6). The daily liveweight gain obtained with high moisture grain v/as significantly higher (P<0.01) (Duncan, 1955) than with both maize silages and dehydrated maize pellets. Geay and Liénard (1971) obtained an even higher weight gain (1539 g/day during an experimental period of 139 days) with 12 bulls fattened with high moisture grain between 356 and 570 kg liveweight. Dexheimer et al. (1971) , Miller et al. (1971) , Forsyth et al. (1972) , Self and Hoffman (1972) and Wilson et al. (1972) also obtained good results with fattening steers fed on high moisture grain or on artificially dried grain. The mean daily liveweight gains obtained with the different batches of dehydrated maize pellets are significantly different (P 0.05); this is due to the difference in digestibility and net energy content. In spite of a higher dry matter intake per day and per kg metabolic weight for the two rations of maize pellets compared with the two silage rations, the liveweight gain was not significantly different. We calculated a significant regression equation (Figure 1) between daily gain (y) and net energy intake/kg W 0 · 7 5 (x).

357 TABLE 6 PERFORMANCE OF BULLS FATTENED WITH MAIZE SILAGE, MAIZE PELLETS AND HIGH MOISTURE GRAIN (MEAN VALUES OF 3 EXPERIMENTS AND STANDARD ERRORS OF THE MEANS)

Basic feedstuff

Height of cut (cm)

Number of bulls (groups) Initial liveweight (kg) Final liveweight (kg) Experimental days Daily liveweight gain (g)

Daily feed intake (kg) - concentrate - maize silage - maize pellets - high moisture grain - dry matter - digest, crude protein - starch equivalent

Daily intake(g/kg W0·75) - dry matter - digest, crude protein - starch equivalent

Intake/100 kg liveweight (kg) - dry matter - digest, crude protein - starch equivalent

Feed conversion (kg) - concentrate - maize silage - maize pellets - high moisture grain - dry matter - digest, crude protein - starch equivalent

Slaughter data (%) - weight loss after 20h fasting

- dressing out

Feed cost price!**) (BF/kg gain)

Maize

13-17

39 (5) 277.5 565.5 245.7 1172ab

+24.8

4.05 17.68 --7.44 0.985 5.16

80.0 10.6 55.5

1.77 0.234 1.22

3.45 15.08 --6.35 0.840 4.40

2.30a +0.13 63.21a +0.30

35.7

silage

33-38

39 (5) 278.7 565.9 240.6 1194ab

+21.4

4.05 17.66 --7.54 1.017 5.23

81.0 10.9 56.2

1.79 0.241 1.24

3.39 14.79 --6.32 0.852 4.38

2.48a +0.16 63.24a +0.31

35.8

Maize pellets

10-15

36 (5) 278.4 575.3 241.8 1228a<*> +25.8

4.11 -5.59 -8.47 1.004 5.78

90.2 10.7 61.6

1.98 0.235 1.35

3.35 -4.55 -6.90 0.818 4.70

2.30a +0.14 62.51a +0.31

45.7

38-40

36 (5) 278.1 558.3 245.4 1142b +21.1

4.07 -5.30 -8.12 0.935 5.38

87.9 10.1 58.2

1.94 0.224 1.29

3.56 -4.64 -7.11 0.819 4.71

2.34a +0.15 61.71b +9.35

49.9

High moisture grain

20 (3) 275.6 563.7 201.4 1431c +34.8

4.04 --7.08 7.38 1.Ö97 6.29

79.6 11.8 67.9

1.76 0.261 1.50

2.82 --4.95 5.16 0.767 4.40

2.93t +0.14 63.10a +0.44

44.9 (*) Means on the same line bearing different superscript letters differ

significantly at P<0.05 or 0.01 (Snedecor and Cochran, 1967; Duncan, 1955).

(**) Unit price per kg feed: 0.65 BF and 0.7 BF for the 2 silages; 4.5 BF and 5.0 BF for the 2 maize pellets; 4.3 BF for the high moisture grain (65% DM); 7.5 BF for the concentrate.

358

1500

1400

1300

1200

1100

1000

DAILY GAIN (g)

y = 17,85X + 166,5 r = 0 ,87* *

oMAIZE SILAGE ■ DEHYDRATED MAIZE PELLETS • HIGH MOISTURE CORN

INTAKE (g)S.E. /Kg W0·

7 5

50 55 60 65 70 75

Figure 1 Daily gain related to net energy intake

In accordance with most of the French authors (ITCF, 1970a , Lelong and Fekete, 1971 and Malterre et al. 1971), the feed efficiency of maize silage was higher than that of maize pellets. Even when the daily gain was sometimes slightly higher for the rations of maize pellets (such as reported by Marchadier, 1970), the dry matter and calculated starch equivalent intake per kg liveweight gain was lower for the maize silage rations compared to those of maize pellets. The dressing percentage and the feed cost price were also in favour of the maize silage rations.

From the mean levels of liveweight gain (Table 6) and the mean yields obtained in 1970, 1971 and 1972 (Table 7) we calculated that between 8.7 and 9.6 bulls per ha can be fattened

359 from 275 to 575 kg liveweight when dough-dent maize is ensiled or dehydrated. With high moisture grain, only 6.1 bulls can be fed per ha.

For both methods of conserving the whole-crop maize (silage or dehydration) the lower height of cutting gave a higher output of beef per ha. The net energy content together with the output figures per ha show that additional yield rather than superior energy content was the major factor contributing to the improved output of beef per ha.

TABLE 7

BEEF PRODUCTION PER HA OF MAIZE (MEAN YIELDS 1 9 7 0 + 1 9 7 1 + 1972 ) ( 1 7 0 BULLS, LIVEWEIGHT INTERVAL: 2 7 8 - 5 6 6 kg)

Basic feedstuff

Height of cut (cm)

Yield (kg/ha) Dry matter content (%) Dry matter yield (kg/ha)

Useful feed - percent - kg feed/ha

Feed conversion (kg) Kg liveweight gain/ha Kg concentrate supplement/ha

Maize

13-17

54 200 22.6

12 250

77.7 42 113

15.1 2 789

9 622

silage

33-38

47 7C0* 23.9

11 4GC

81.4 38 828

14.8 2 624

8 8?5

Maize pellets

10-13

(89)

12 250

95 13 076

4.55 2 874

9 628

38-40

(89)

11 400

95 12 169

4.64 2 623

9 338

High moisture grain

8 000 (65)

5 200

97.5 9 068 (55.8% DM) 4.95 1 836

5 178

* Maize harvested between 33 and 38 cm yielded on average 12% less than maize cut between 13 and 17 cm.

COMPLETE DRY RATIONS FOR INTENSIVE BEEF PRODUCTION BASED ON DEHYDRATED WHOLE-CROP MAIZE PELLETS

Complete r a t i o n s i n c l u d i n g d e h y d r a t e d ma ize p e l l e t s from 0 t o 70% i n compar i son w i t h r o l l e d b a r l e y o r w i t h g round ma ize g r a i n have been s t u d i e d w i t h 41 and 72 young f a t t e n i n g b u l l s (140 - 490 kg l i v e w e i g h t ) r e s p e c t i v e l y . The r e s u l t s have

360 already been published by Boucqué et al. (1971) and Boucqué et al. (1973).

MAIZE SILAGE WITH OR WITHOUT NPN SOURCES AS BASIC FEED FOR YOUNG FATTENING BULLS (PRELIMINARY RESULTS)

Experimental Because the protein content of maize silage is low, the

addition of NPN sources to the silage can be a valuable supple­ment to this high energy feed. During 1973 and 1974 two sources of NPN were added to dough­dent maize (Anjou 210) just prior to ensiling: Pro­Sil (2.39% in 1973 and 1.94% in 1974 added to the fresh mass) and Rumipec at 1% added. Each year control maize silage which received no additive was stored in trench silos. Rumipec is a dry granulated commercial product composed of urea (50%), minerals (5.2% P, 10% Ca, 2% S, 2% Mg) and micro­elements (Fe, Zn, Mn, I, Co). Pro­Sil is an ammonia­mineral suspension developed at Michigan State University containing 85% crude protein equivalent (16.6% NH3), 9% molasses, 4.3% Ca, 1.5% Ρ, 1.3% S, 3.2% Na, 12.2% Cl and traces of Zn, Cu, Mg, I and Co (Henderson and Britt, 1974).

The beef production experiments were carried out with 4 groups of young white­blue bulls; 2 groups were given the control silage ad libitum; one of them (the negative control) received a concentrate of only 6.5% DCP, while the second (positive control) was supplemented with a concentrate of 11% DCP (5% groundnut meal + 5% cottonseed meal + 15% rapeseed meal were added to the concentrate based on grain and dried beet pulp). The third and fourth groups were given the Pro­Sil silage and the Rumipec silage; both of these groups were also given the low protein concentrate (6.5% DCP). Concentrate was offered to each group at 0.75% of liveweight and was adjusted every 4 weeks. Two series of animals were kept in loose houses on straw bedding while the bulls of the third series were individually tied up. Results and discussion

The chemical composition, digestibility (determined with sheep) and the net energy content of the feeds are presented in Table 8. The digestibility of the organic matter and especially of the protein fraction was higher for the treated silages than

361 for the control. Huber and Thomas (1971) and Andrieu and Demarquilly (1974) also noted an increase in digestibility when urea was added to maize silage.

In earlier experiments Boucqué et al. (1974) found no influence of a urea treatment on tha di^astibility of maize silage. The addition of 2.39% or 1.94% Pro-Sil or 0.5% urea to maize at the time of ensiling increased considerably the digestible crude protein content of the silage. In 1974, however, the increase for the Pro-Sil treated silage was lower than in 1973; this is not only due to the lov/er dose (1.94%) but also to the extremely difficult harvest circumstances in the field caused by high rainfall which made a good co-ordination between the chopper and the Pro-Sil tank quite impossible; this situation enhanced NH3 losses during the chopping process. TABLE 8 MEAN DIGESTIBILITY AND FEEDING VALUE OF FEEDS

Year

1973 -74

1974 -75

Feeds

Maize silage 1. Control 2. Pro-Sil (2.4%) 3. Rumipec (+ 1%) Concentrate 1. Negat, contro] 2. Posit, control 3. Pro-Sil 4. Rumipec

Maize silage 1. Control 2. Pro-Sil (1.9%) 3. Rumipec (1%) Concentrate 1. Negat, control 2. Posit, control 3. Pro-Sil 4. Rumipec

Digestion coefficients

Organic matter

69.9 75.0 72.2

--

72.7 75.0 74.4

--

(sheep) Crude Protein

58.2 73.2 75.2

----

58.7 73.2 70.2

_ ---

N-free extract

73.9 77.2 74.6

-· --

76.8 77.2 77.3

. -·--

Dry mat­ter (%)

25.6 26.3 26.3

84.2 85.0 83.7 84.3

26.7 25.4 26.7

85.5 85.2 84.5. 85.2

% of

Digest, crude protein

5.4 9.9 10.4

7.7 12.7 8.7 7.6

5.2 7.9 9.4

7.7 12.8 7.6 7.7

DM

Starch equivalent

62.1 66.8 63.0

75.9 76.8 76.7 77.0

64.7 66.7 65.3

75.2 76.1 76.2 76.0

362 From the results shown in Table 9 it can be concluded that

during the first 140 days of the fattening period, the NH3 and urea treated maize silage gave an increase in feed intake to the same extent as did the positive control, compared with the negative control group, but the effect on daily gain was less for groups receiving NPN than for the plant protein group. During the second part of the trial (from 140 days until the end) however, the daily gain of both NPN groups was significantly higher than for the negative and positive control, owing to a higher net energy intake.

For the entire fattening experiment the addition of both NPN sources in the maize silage or the incorporation of plant protein in the concentrate resulted in a higher protein and net energy intake and a significant increase (P <0.05) of the growth rate compared with the negative control. These results prove that 6% digestible crude protein in the dry matter of the total ration is only sufficient to obtain a daily gain of 1 kg with young bulls. In a review article concerning fattening experi­ments in France, Fekete (1974) cited an average decrease of 10% of the daily gain when urea was added to maize silage instead of plant protein sources. Essig (1969) , Meiske et al. (1969) , Wilkinson et al. (1973) and many other American authors, obtained satisfactory results with urea treated maize silage for beef cattle. Many reports from Michigan State University demonstrate the good animal performance obtained vith Pro­Sil treated maize silage.

Owing to the highest daily gain, the feed conversion was somewhat better for the Pro­Sil treatment than for the other groups. The increase of the Ν level in 3 out of the 4 rations improved not only the daily gain but also the slaughter results. Taking into account the present price ratios between plant protein sources and the NPN sources, the decrease of the con­centrate price (Table 9) could not compensate for the increase in the cost of the silage when NH3 or urea were used instead of plant protein.

TABLE 9 PERFORMANCE OF BULLS FATTENED ON MAIZE SILAGE TREATED WITH NPN (MEAN VALUES OF 2 EXPERIMENTS + SE)

363

Experimental group

Number of bulls (groups) Initial liveweight (kg) Weight at 140 days (kg) Final liveweight (kg) Experimental days Daily liveweight gain (g) - from start to 140 d. - from 140 d. to end - total exper. period Daily feed intake - concentrate - maize silage - dry matter - digest, crude protein - starch equivalent Daily intake(g/kg W0

·75)

1. From' start to 140 d. - dry matter - digest, crude protein - starch equivalent

2.From 140 d. to end - dry matter - digest, crude protein - starch equivalent

3. Total exper. period - dry matter - digest, crude protein - starch equivalent

Feed conversion (kg) - concentrate - maize silage - dry matter - digest, crude protein - starch equivalent Slaughter data (%) - weight loss after 20h fasting

- dressing out Feed cost price (BF) - per kg concentrate - per kg silage (**) - per kg gain

Negative control

21 (3) 287.3 423.5 545.6 257.4

973a*+ 34

1040a + 40

1004a + 32

2.99 18.1 7.29 0.445 4.93

81.7 5.0 55.1

77.5 4.7 52.6

79.1 4.8 53.5

2.98 18.1 7.27 0.444 4.91

2.53a+0.15

62.52a+0.26

6.85 0.65 32.2

Positive control

21 (3) 289.3 449.4 566.7 255.3

1144b + 42 1017

a + 34 1087b + 33

3.12 19.2 7.71 0.604 5.24

84.5 6.5 57.1

78.8 6.3 53.7

81.9 6.4 55.7

2.88 17.7 7.10 0.556 4.82

2.03a+0.14

63.43b+0.28

7.40 0.65 32.8

Pro-Sil

21 (3) 289.9 438.4 578.8 259.7

1061ab+ 38

1173b + 31

1112b + 20

3.11 19.3 7.57 0.630 5.29

82.1 6.9 57.2

78.6 6.5 55.2

79.5 6.6 55.6

2.79 17.4 6.81 0.566 4.76

2.41a+0.12

63.45b+0.23

6.75 0.86 33.8

Rumipec

20 (3) 288.2 431.7 570.8 260.8

1025a + 39

1152b + 38

1084b + 19

3.07 19.3 7.74 0.693 5.30

85.1 7.7 58.0

80.9 7.2 55.7

82.1 7.3 56.2

2.83 17.8 7.15 0.639 4.89

2.44a+0.19

63.69b+0.31

6.75 0.77 32.8

(*) Means on the same line bearing different superscript letters differ significantly at Ρ <0.05 (a, b)

(**) Cost price of Rumipec: 10 BF/kg; Pro-Sil: 8.16 BF/kg

364

CONCLUSION The feeding value of maize silage is generally higher than

that of dehydrated whole­crop maize pellets. Maize silage is a highly palatable feed that enables

economical production of beef. Beef production rations based on maize silage require

supplementation with crude protein in order to obtain high animal performance. NPN sources may be added at ensiling time to supply a portion of the crude protein in rations containing large amounts of maize silage.

ACKNOWLEDGMENT

The authors are indebted to Mr. J. Vanacker (T. ing.), F. Verhaegen and A. Hertegcnne for skilled technical assistance.

FEFERENCES

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Boucqué, Ch.V. Cottyn, B.G. and Buysse, F.X. 1971 Maïs déshydraté et orge aplatie dans des rations complètes pour taurillons à l'engrais. Revue de l'Agriculture 24: 1295.

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365

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367

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Animal Feed Science and Technology, H\976) 369-379 3 6 9 Elsevier Scientific Publishing Company. Amsterdam - Printed in The Netherlands

ENERGY SUPPLEMENTATION OF MAIZE SILAGE HARVESTED AT DIFFERENT MATURITY STAGES

A. GIARDINI, M. VECCHIETTINI and A. LO BRUNO CNR - Centro di Studio per la Conservazione dei Foraggi, Agronomy Department, University of Bologna, Italy.

ABSTRACT

Trials were carried out in order to define the most con­venient harvest stage for maize silage and high moisture grain used in the fattening of young bulls.

The best results were obtained with the riper forage (harvested at 39% DM content) in an all-maize silage ration, i.e. without the addition of concentrates.

Earlier harvests (24% and 28% DM) gave rations with a higher feed efficiency of the DM but were not feasible because of the lower crop yield and the higher feeding costs.

This trend proves that, within the limits of the maturity stages considered in our trials, the crop yield is the most important factor.

The addition of concentrates (1% LW per day) improved the animals' performance (daily gain, dressing %, feed efficiency), but increased the ration's cost and reduced the number of head/ ha which could be fed. On the whole, the effect of concentrates was indirectly correlated with the stage of maturity of the crop, improving the technical results obtained with early and regular maize silage and reducing those obtained with ripe forage.

The comparison between dry maize meal and high moisture grain shows similar technical results for these two forms of supplement.

INTRODUCTION

Our previous investigations on beef cattle fattening (Baldoni et al., 1971; Giardini, 1970; Giardini and Vecchiettini, 1975a and b) with maize silage harvested at different maturity stages and supplemented with 1% LW/day of concentrates, showed the clear superiority of the dough stage (32 - 33% forage DM content). Earlier harvesting (22 - 25% DM) gave a tendency to higher technical

370 results but with a lower net return owing to lower crop yield. Later harvests (40-42% DM) furnished lower daily gains, higher feed intake and more unfavourable feed efficiency (8-10% less compared to the regular maize silage).

Similar results, at least as a trend, are found in the literature (Byers and Ormiston, 1964; Geasler et al., 1967; Geasler and Henderson, 1968; Gordon et al., 1966; Henderson and Greathouse, 1969; Henderson et al., 1971; Hourmant and Fekete, 1970; Huber et al., 1965; ITEB, 1973; Johnson & McClure, 1968; Nelson et al., 1969; Noller et al·., 1962; Owens et al., 1967; Pratt et al., 1964), where the lower nutritive value of the ripe forage is explained both by the greater lignification of the stalk fibre, and by a lack of assimilation of the grain which, when too hard, is easily left undigested by the animal.

Today's availability of harvesting machines which permit a much shorter cutting and a higher shattering percentage of the kernels, re-opens the problem concerning the time of harvesting maize silage with reasonable prospects of improving the results obtained to date with riper forages. Therefore we conducted some further trials on this subject. One was concerning the comparison, in a factorial design, among three stages of maturity of maize silage (24-28-39% DM at harvest) with two energy levels (all silage ration vs. silage + 0.7% LW/day of concentrate as shelled maize grain). Because all the animals received 1 kg/head/ day of 40% protein supplement, the two definitive concentrate rates were 0.3% and 1% LW/day respectively. The second experi­ment was carried out in order to compare two kernel moisture levels (38 and 34%) and dry meal in a factorial design with two maize silage maturity stages (24 and 28% DM at harvest). The ration was based on silage ad libitum + 1% LW/day of concentrates as dry meal.

The trials were conducted on young Polish Holstein bulls raised in slotted floor housing, from an initial weight of 240 kg to a slaughtering weight of 420-440 kg. The animals were weighed every 15 days and each time the concentrate level of the ration was adjusted to the average body weight recorded for the group.

The maize forage characteristics are given in Table 1. Table 2 shows the chemical composition of the single feed

and of the daily rations together with the costs, calculated

371

TABLE 1 DRY MATTER CONTENT AND PLANT COMPOSITION OF MAIZE FORAGES HARVESTED AT THREE DIFFERENT MATURITY STAGES

Harvest stage

Milk stage Dough stage Late dough stage

DM (%) 24.0 29.4 39.1

Plant composition (% of DM) stalk 33 30 22

leaves 19 18 18

husks 10 8 6

cob 10 9 9

kernels 28 35 45

TABLE 2 CHEMICAL COMPOSITION AND COSTS OF THE FEEDS AND THE RATIONS

Feeds and rations

Early maize silage Regular maize silage Late maize silage High moisture grain High moisture grain Shelled grain (dry meal) Protein supplement 3 Rations Experiment 1 All maize silage:early

regular late

1% LW/day concentrate: early- maize silage

regular maize silage late maize silage

Experiment 2 Early maize silage: dry meal high moisture 66.6% high moisture 62.3% Regular maize silage: dry meal high moisture 66.6% high moisture 62.3%

DM (%)

23.9 28.2 36.9 66.6 62.3 85.5 91.0

26.6 30.8 39.8

33.0 37.8 47.1

33.2 32.4 32.2

37.9 36.3 36.3

Chemical composition (% crude

Prot.

8.7 8.5 8.6 10.4 10.4 9.6 45.8

13.9 13.3 13.1

13.5 13.1 14.0

13.3 13.7 13.7

13.1 13.3 13.4

values in DM) Ether extr. 2.7 2.6 2.3 4.6 4.4 4.3 0.6

2.4 2.4 2.1

2.9 2.8 2.6

2.9 3.0 2.9

2.8 2.9 2.8

Fibre

26.1 23.5 23.1 3.1 2.8 3.1 8.2

23.6 21.6 21.3

17.6 16.4 16.2

17.8 17.7 17.5

16.4 16.7 16.3

N-free extr. 56.7 59.8 60.6 80.4 80.8 81.6 31.5

53.2 56.0 57.1

60.4 62.2 61.9

60.4 60.6 60.3

62.2 61.5 61.9

Ash

5.8 5.6 5.4 1.5 1.6 1.4 13.9

6.9 6.7 6.4

5.6 5.5 5.3

5.6 5.6 5.6

5.5 5.6 5.6

Costs Lit/100" kg DM

9000 1 8000 1 7000 1 15000 1 15O0O 1 15300 1 18000 2

10260 9275 8335

11835 11075 10433

11750 11730 11760

11080 10900 11020

'Opportunity cost' vs. dry shelled maize grain (9.0 t/ha at Lit. calculated on the following parameters:

125 OOO/t)

early maize silage regular maize silage late maize silage high moisture grain

3 Composition:

yield 14.3 t/ha DM and 12.5% storage losses ge : " 15.9

: " 17.7 η : " 7.6 at farm Soyabean meal Colza meal Urea

II II II

Dicalcium phosphate Calcium carbonate Mineral mix Calcium sulphate Vitamins A and D

" " 11 ti π g

Il II o

40% 43% 4% 5% 2% 5% 1%

1300 g/t

0% 0% 5%

372 on the current market price for the feed bought and on the "opportunity cost" for the forages produced on the farm.

Table 3 summarises the technical results of the first trial.

DAILY GAIN

The average daily gains increased with the increase in the ration's concentrate level and proved to be almost independent of the forage's harvest stage. However, an interaction, "type of silage χ energy level" was recorded: the daily gains increased with the delay in date of harvest for the all silage rations, whereas they decreased in the 1% concentrate diets. The addition of concentrates was more effective with the more immature forage, with differences in the daily gains reaching 226, 168 and 37 g, respectively for the early, regular and late harvests.

FEED INTAKE

The feed intake increased with the increase in DH% (r = 0.96**) and with the decrease in the acid content (r = 0.95**) of the ration, either because of the effect of the delay in harvest or else as a consequence of the concentrate supplementation. The highest daily intake increases occurred, however, between the first and second harvest stage, particularly in the all­maize­silage rations.

For each 1% increase in the maize silage DM content, the daily intake of DM increased:

for the all maize silage rations: 135 and 40 g respect­ively from early to regular harvest maize silage and from regular to late; for the 1% LW/day concentrate rations: 80 and 6 g, in the same order as above.

The lower increases in the late harvested forages, both with and without concentrates, could be explained by greater stalk lignification which increases the work of chewing, thus reducing palatability. The concentrate added also gave differ­ent increases in feed intake depending on the maize silage harvest stage: in fact, the increase in daily DM intake was 980, 720 and 430 g respectively for early, regular and late maize silage.

The reduction in the daily maize silage intake is of

TABLE 3 TECHNICAL RESULTS OF THE FIRST EXPERIMENT

^^■^^ Rations

Parameters ^^^

Average daily gain kg Daily feed intake: Maize silage kg Shelled corn kg Protein supplement kg Dry matter kg DM (% LW/day) Roughage: concentrate 2 Dressing % 3

Feed efficiency: Live weight kg DM/kg Carcass weight kg DM/kg

Yield/ha: 4

No. of cattle Live weight kg Carcass weight kg

All Early

U)

0.985

23.4 -

1.0 6.51 1.95

63:37 56.18

6.60 12.37

7.45 2200 1175

maize silage Regular

U)

1.027

22.2 -

1.0 7.15 2.14 56:44 56.65

6.96 12.93

7.56 2330 1250

Late (J)

1.078

17.8 -

1.0 7.49 2.23 48:52 57.18

6.95 12.79

8.16 2640 1430

1% Early

1.211

19.3 2.4 1.0 7.49 2.12 44:56 57.88

6.18 11.24

5.24 1900 1045

ι

concentrate Regular

1.195

17.4 2.4 1.0 7.87 2.30 40:60 58.48

6.60 11.80

5.37 1925 1070

Late

1.115

13.4 ;

2.4 1.0 7.92 2.41 34:66 58.74

7.10 12.72

5.73 1915 1070

Averages All maize silage

1.030

21.1 -

l.O 7.05 2.11 -

56.67

6.84 12.70

7.72 2390 1285

1% cone.

1.174

16.7 2.4 1.0 7.76 2.28 -

58.37

6.61 11.95

5.45 1913 1062

Early

1.098

21.3 1.2 1.0 7.00 2.04 -

57.03.

6.38 11.78

6.35 2050 1110

Regular

1.111

19.8 1.2 1.0 7.51 2.22 -

57.56

6.76 12.36

6.47 2128 1160

Late

1.09'

15.6 1.2 1.0 7.70 2.32 -

57.96

7.02 12.75

6.95 2278 1250

1 Early = 23.9% DM and 28% DM'grain in total 2 Including the grain contained in the maize 4 Considering the average presence to be 3O0

DM; regular = 28.2 and 35.5%; late = 36.9 and 45.0% silage '6 Hot carcass weight - 2%/farm live weight - 5% days/yeer.

374

particular interest: for each kg of concentrate DM fed, the sil­age DM intake decreased by 430, 650 and 7 90 g, again for early, regular and late maize silage. These quantities correspond to about 2 kg of maize silage for all the cases. This means that within the limits considered in our trials, the daily feed in­take is reduced by about 1 kg for each kg of concentrate added.

DRESSING PERCENTAGE

This factor increased with the delay in forage harvesting and with the increase in the ration energy level. It is evident, therefore, how this is directly correlated to the ration's con­centrate content (r = 0.98**) independently of the diet's fibre quality, the kernel's degree, of ripeness and physical'state. In our trials, for every 1% more of concentrates in the diet, the dressing percentage increased by 0.105. In other words, in order to obtain a variation of one point on the dressing percentage, the diet's concentrate content will have to be varied by about 10?

FEED EFFICIENCY

The best results were obtained with the early maize silage 1% concentrate ration. Delay in the forage harvesting caused a deterioration in the feed efficiency both with or without con­centrate supplementation. Concerning the effects of this last factor, an evident interaction with the forage harvesting stage was recorded: the concentrate addition improved the feed efficiency of earlier forage rations, whereas it did not show any effect with the riper maize silage.

On the whole these results clearly show the negative effect of the delay in harvesting and of concentrate supplementation on the nutritive value of the forage DM. These trends are evident in Table 4 which gives the relative forage nutritive values, with reference to estimated values of 80, 133 and 120 FU/ 100kg DM for regular maize silage without concentrate, dry maize meal and protein supplement respectively.

TABLE 4 RELATIVE FU/100 kg DM OF MAIZE SILAGE

375

All maize silage 1% LW/day concentrate

Early

84 80

Regular

80 72

Late

81 61

In order to give a practical definition of the best harvest stage for maize silage and of the convenience or not of concen­trate integration, in Table 5 the economic results forecast in the current market situation for beef in Italy are reported. These results were calculated in reference to a maize crop with a yield of 9.0 t of shelled maize/ha, equal, as recorded in the agronomic and storage trials, to a yield of 12.5, 14.1 and 16.1 t/ha DM of maize silage at feeding, respectively for the early, regular and late harvests.

The 'oest net profits, in absolute terms, per ha of trans­formed forage crop, are obtained with the late maize silage (about 40% and 60% DM content in the whole plant and grain, respectively) and without concentrates.

The forage from the early harvest, in spite of its higher nutritive value, furnished disappointing economic results owing to either low crop yield or to a limited energy level of the forage itself ( 21.7 FU/100 kg). The concentrate supplementation of this forage improves the economic results remarkably, so much so as to bring them up to values almost equal to those obtainable with the riper fodder. In other words, the 1% concentrate rations tend to level out the economic results of the fattening enterprise making them practically independent of the forage harvest stage, whereas, in the all-maize-silage rations it is more convenient to use riper forages.

Therefore, in a final analysis, from an economic point of view, the optimum harvest stage for maize silage seems to correspond to the vegetative stage with maximum dry matter yield of the crop, without excluding the possibility of a later harvest, obviously taking care to do a more accurate chopping with a shattering of most of the kernels. Research on the utilisation of machines with a reel for harvest at the advanced dough stage, with forage at

TABLE 5 ECONOMIC RESULTS OF THE FIRST EXPERIMENT

"~"~—— ^ Rations

Parameters ~~~~­~­___

Feed costs: ­ per kg gain of LW Lit ­ per kg gain of carcass Lit Net return per year 1

­ per head 1000 Lit ­ per ha 1000 Lit

All maize silage early

678 1270

7 52

regular

646 1200

28 212

late

580 1067

63 510

1ΐ concentrate early

732 1330

38 200

regular

729 1313

49 263

late

741 1328

44 252

Averages all

maize silage

635 1179

33 258

1% concen­

trate

734 1324

44 238

early regular

705 688 1300 1257

23 39 126 238

late

661 1198

54 381

1 Considering a buying price of 1650 Lit/kg LW, for costs other than for feeding.

TABLE 6 TECHNICAL AND ECONOMIC RESULTS OF THE SECOND EXPERIMENT

a sale price of 2500 Lit/kg of hot carcass ­2%, and 250 Lit/head/day

­^_^ Rations

Parameters ~"~——

Average daily gain Daily feed intake: ­ maize silage ­ concentrate ­ protein supplement ­ DM

Dressing Feed efficiency

Live weight kg Carcass weight kg

No. of head/ha Feed cost/kg LW gain

kg

kg kg kg kg %

DM/kg DM/kg

no Lit

Early maize silage dry meal

1.173

19.9 2.45 1.00 7.76 58.05

6.62 12. OO 5.06 778

high moist. 67%DM 1.107

18.7 2.99 1.00 7.36 59.31

6.65 11.80 5.33 780

high moist. 62%DM 1.107

18.7 3.28 1.00 7.41 59.06

6.69 11.92 5.28 787

Regular maize dry meal

1.157

17.4 2.45 1.00 7.91 58.65

6.84 12.28 5.47 758

high moist. 67%DM 1.148

17.8 2.99 1.00 7.92 59.82

6.90 12.14 5.48 752

silage high moist. 62%DM 1.153

17.0 3.28 1.00 7.74 59.67

6.71 11.85 5.57 739

Averages early maize silage 1.129

19.1 2.91 1.00 7.51 58.81

• 6.65 11.91 5.22 782

regular maize silage 1.153

17.4 2.91 1.00 7.86 59.38

6.82 12.09 5.51 750

dry meal

1.165

18.7 2.45 1.00 7.84 58.35

6.73 12.14 5.27 768

high moist. 67%DM 1.128

18.3 2.99 1.0O 7.64 59.57

6.78 11.97 5.41 766

high moist. 62%DM 1.130

17.9 3.28 l.OO 7.58 59.37

6.70 11.89 5.43 763

377 more than 40% DM, would be of practical interest, also in view of a desirable prolongation of the harvesting season.

With regard to the different sources of concentrate, dry meal and high-moisture grain with different DM content, the results obtained (Table 6) showed a very slight technical advantage in favour of the high-moisture grain.

CONCLUSIONS

Once again the results obtained in these trials show the great importance of the stage of harvest of maize silage for technical and economic performance in beef cattle raising.

Forage harvested early, on the whole, has higher DM nutritive values but with decidedly unfavourable technical and economic results owing to the lower crop yield a'nd forage energy content.

Concentrate supplementation clearly improves the livestock raising performance of this forage with a tendency towards a levelling of the economic outcome of the livestock enterprise independently of the forage harvest stage.

Highest profits were obtained with the forage harvested in advanced dough stage (38-40% DM) and without concentrate supple­mentation.

In practice, the most important and decisive element for the choice of the harvest stage seems to be represented by the productive level of the crop. The better quality and higher feed efficiency value of the immature forages does not appear to be sufficient to compensate for the lower DM yields in the earlier harvests.

Obviously if in this stage of the crop's maximum production the forages should prove .to be too dry and the kernels too hard (respectively more than 40% and 60% DM), it would be logical to foresee the need for very short cutting with shattering of the kernels. In our opinion this is one of the most interesting fields for future research in all of the traditional maize environments where the growing season is long enough to reach the advanced dough stage even for the late hybrids.

In the more northern countries, and even in the second crops of the Mediterranean areas, the problem raised is whether to grow early hybrids for harvest at the dough stage or late hybrids

378 for early harvests ­ two solutions v/ith approximately the same yield.

In these conditions, considering the technical results obtained in our experiments, the late hybrid with 1% concentrate rations, represents the most economically convenient solution. Of great interest, especially in these environments, but also in normal growing conditions, is the research concerning higher plant populations, owing to the well­known positive effect of this factor on the productive level of the crop.

REFERENCES

Baldoni, R., Giardini, A. and Vecchiettini, M. , 1971. Ricoveri, Silomais e "pastoni" nell'allevamento del vitellone. L'Informatore Agrario, 28.

Byers, J.H. and Ormiston, E.E., 1964 Feeding value of mature corn silage. Journal of Dairy Science, 47, 707.

Geasler, M., Henderson, H.E. and Hawkins, D.R., 1967. Effect of stage of maturity and fineness of chop on yield per acre and feeding value of corn silage. Michigan State University, Report AH­BC­666.

Geasler, M. and Henderson, H.E. 1968. Effect of stage of maturity and fineness of chop on yield per acre and feeding value of corn silage. Michigan State University, Report AH­BC­676.

Giardini, Α., 1970. Il Silomais nel'alimentazione del vitellone. Alimentazione Animale, 3, 11­26.

Giardini, A. and Vecchiettini, Μ., 1975a I cereali foraggere nell'allev­amento del bovino da carne. L'Informatore Agrario, 7, 18353­18369.

Giardini, A. and Vecchiettini, M., 1975b, The cheapest feed for beef cattle on dry and irrigated land in northern Italy. Communication presented at EEC Seminar on Improving the nutritional efficiency of beef production. Clermont Ferrand, 14­17 Oct.

Gordon, C.H., Derbyshire, J.C. and Humphrey, J.L., 1966. The value of mature corn for silage. USDA, ARS, 44, 176.

Henderson, H.E. and Greathouse, T., 1969. Corn silage for feedlot cattle. Michigan State University, Report AH­BC­42.

Henderson, H.E., Ritchie, H. , Allen, CK. and Cash, E., 1971. Effect of housing systems and corn silage maturity on feedlot performance of Holstein steers. Journal of Animal Science, 33, 1140.

Hourmant, G. and Fekete, J., 1970. Utilisation du maïs fourrage pour la production de jeunes bovins. ITCF, Compte rendu d'essais, no. 6.

379

Huber, J.T. , Graf, G-.C. and Engel, R.W. , 1965. Effect of maturity on nutritive value of corn silage for lactating dairy cows. Journal of Dairy Science, 48, 1121.

Institut Technique de l'Elevage Bovin, Thieux, 1973. Le Mais Fourrage. Johnson, R.R. and McClure, K.E., 1968. Corn plant maturity. IV-Effects on

digestibility of corn silage in sheep. Journal of Animal Science, 27, 535.

Nelson, L.V. , Hildebrand, S.C., Henderson, H.E., Hillman, D., Höglund, CR., Maddex, R.L. and White, R.G., 1969. Corn silage. Production, harvest and storage in Michigan. Michigan State University, Co-operative Extension Service.

Noller, C.H., Warmer, J.E., Rumsey, T.S. and Hill, D.L., 1962. Comparative digestibilities and intake of green corn and corn silages with advancing maturity. Journal of Animal Science, 22, 1135.

Owens, M.J., Jorgensen, N.A., Mohanty, G.P. and Voelker, H.H., 1967. Feeding value of high dry matter corn silage. Journal of Dairy Science, 50, 983.

Pratt, A.D., Conrad, H.R. and Triplett, G.B., 1964. The effect of stage of maturity on dry matter yield and digestibility of corn silage. Dairy Science Department Service, 8, Wooster, Ohio, USA.

Animal Feed Science and Technology. 1(1976) 381­392 381 Elsevier Scientific Publishing Company. Amsterdam ­ Printed in The Netherlands

FACTORS INFLUENCING THE COMPOSITION AND NUTRITIVE VALUE OF ENSILED WHOLE­CROP MAIZE

J. ANDRIEU Institut National de la Recherche Agronomique, Centre de Recherches Zootechnigues et Vétérinaires, Theix ­ 63110 ­ Beaumont, France.

Much work has been carried out in the United States and in Europe on the composition and nutritive value of whole­crop maize silages. This report summarises the results obtained in our laboratory, published in part (Andrieu and Demarquilly, 1974a,b,c; Demarquilly and Andrieu, 1973) , and discusses them in the light of the very exhaustive reviews published on this subject, (see especially: Owen, 1967; Coppock and Stone, 1968; Hillman, 1969) .

Since 1967, we have made 122 whole plant silages from 15 varieties of maize, mainly early or half early (FAO index under 300) commercialised in France for seed production. These crops were harvested between the milk stage (20% dry matter in the plant) and physiological seed maturity ( about 40% dry matter in the plant) with forage harvesters with well adjusted blades (plant fragments 0.5 to 1.5 cm long) and ensiled either in air­tight small tower silos of 4 m^ η = 101) or in large trench silos (n = 21). For 67 of the silages, a solid mixture contain­ing 50% urea (with 46% nitrogen) and 50% minerals was added at ensiling at a dose of 10 kg mixture per tonne of freshly cut forage. All the silages were fed alone, ad libitum, to groups of 6 sheep in order to measure their nutritive value.

The results were corrected for the losses of volatile pro­ducts during heating and for this we used the equations proposed by Dulphy et al. (1975).

INTRINSIC EFFECTS OF CONSERVATION

Silage making causes only slight modifications to proximate chemical composition (Andrieu and Demarquilly, 1974a). It re­sults only in a passive increase in crude protein content (about 4%) and in crude fibre content (about 7%).

The main modifications due to conservation concern principally

382 the carbohydrate fraction of the plant and the nature of the nitrogen components. Based on the soluble sugars, which dis­appear almost completely, fermentation gives rise to the organic acids, lactic and acetic, and to alcohol (mainly ethanol): the average content of lactic acid, acetic and ethanol is respectively 54.0, 15.2 and 21.2 g/kg of dry matter in the 122 silages we have studied (Table 1). There was little variation between sil­ages in pH, which dropped below 4.2, thus stopping butyric fer­mentation from developing. While the proportion of soluble nit­rogen (as a percentage of total N) sometimes doubled (increasing from 26 to 47% in the case of 35 silages without additive). (And­rieu and Demarquilly, 1974a), the production of ammonia ­ nitro­gen remained low (on average 9% of total nitrogen, η = 122). Losses in the form of effluents were low or non­existent and therefore it is not surprising that reductions in digestibility between the plant in the field and the plant ensiled are negli­gible or absent (Harris, 1965; Noller et al., 1965; Andrieu and Demarquilly, 1974a).

INFLUENCE OF STAGE OF HARVEST

For a maize which develops normally after flowering, the later the harvest the higher the dry matter content. In relation to this, the crude fibre, ash, and, to some extent, total protein contents diminish, (Coppock and Stone, 1968; Demarquilly and Andrieu, 1973). This change results essentially from development of the grain and thus from transformation of soluble sugars into starch in the grain (Andrieu and Demarquilly, 1974a). The starch is not affected by fermentation, the intensity of which diminishes as the harvest is made at greater maturity (Table 1). With between 20 and 40% dry matter in the whole plant, conservation quality remains satisfactory.

The coefficient of organic matter digestibility of the 122 silages was high (70% on average) and varied between 59.5 and 76%. The average value is comparable with that obtained by American research workers. For a given variety harvested at dif­ferent stages or for the varieties as a whole, the influence of stage at harvest on the digestibility of green fodder (Demar­

quilly, 1969) or silage was low (Andrieu and Demarquilly, 1974a).

TABLE 1 COMPOSITION AND NUTRITIVE VALUE OF MAIZE SILAGE WITH (+) OR WITHOUT (-) ADDITION OF UREA AND MINERALS AT ENSILING (2)

Dry matter content

20 to 25%

25 to 30%

30 to 35%

35 to 40%

40 to 45%

Total

No. of silages

8 (-)

14 (+)

17 (-)

14 (+)

25 (-)

21 (+)

5 (-)

9 (+)

9 (+)

122

Contribution of ears in

DM«1» (%) 40.9

50.0

57.2

53.4

59.7

58.3

63.2

59.7

61.7

56.4

Silage compo­sition (% DM) Crude prot­ein

8.3

15.0

6.9

12.4

8.0

11.9

8.0

11.9

11.4

Crude fibre

23.9

23.3

20.5

21.0

18.4

18.7

16.9

18.9

19.1

20.0

Silaqe characteristics

pH

3.75

4.05

3.75

4.05

3.80

4.05

3.95

4.20

4.25

3.95

NH3-N (% of total N)

6.6

8.3

5.3

14.2

5.5

12.0

5.1

15.4

11.0

9..0

Lactic acid (3)

62.8

62.4

48.4

57.5

48.5

56.4

46.7

55.7

50.0

54.0

Acetic acid (3)

10.8

22.0

15.5

15.4

13.4

14.1

9.3

13.6

11.1

15.2

Butyric acid (3)

0.2

0.4

0.3

l.O

0.2

0.4

0.2

0.6

0.2

0.4

Ethanol (3)

48.6

48.8

27.6

31.9

12.8

8.7

4.7

4.7

3.7

21.2

Organic matter digest­ibility (%)

68.4Ì1.6

68.4^1.6

69.9-4.2

70.4^2.6

70.3Ï3.4

71.6-2.0

69.0-1.9

70.8^2.7

70.2^1.8

70.1-2.9

(1) Ears = grain + rachis + husks + ear shank (2) A solid mixture containing half urea (46% of nitrogen) and half minerals was incorporated at ensiling at

the rate of 10 kg/tonne of forage maize (3) g/kg of dry matter

384 (Table 1). The slightly lower values mentioned in Table 1 in the case of silages with 20 and 25% dry matter are those with a poor grain content (post-flowering temperatures too low) and late har­vest (on average 63 days after normal harvest date). This con­stancy in digestibility, which has also been observed by many American authors (Coppock and Stone, 1968; Hillman, 1969), is not necessarily true for the net energy value for fattening since the composition of digestible organic matter, notably the starch con­tent, varies considerably with the stage at harvest. However, Chamberlain et al. (1971) found that the stage at harvest did not influence the net energy value for fattening of maize silage. This appears to confirm the fact that, in our trials (Andrieu and Demarquilly, 1974b) , the stage at harvest of maize silages did not influence the composition of sheep rumen liquor. The net energy value for fattening, estimated by Breirem's formula, (Breirem, 1954), was on average 0.75 feed units per kg of dry matter, a value very similar to that calculated by Malterre et al. (1970) from American trials with fattening steers.

INFLUENCE OF VARIETY AND OF ENVIRONMENTAL CONDITIONS

In a given trial, the differences in digestibility due to the varieties are often significant (Andrieu and Demarquilly, 1974a) although of relatively small amplitude (maximum differ­ence : 4.2 units - Table 2). This is probably explainable by the fact that most of the varieties studied were bred for grain pro­duction, often from the same ancestors. It would, no doubt, have been true if we had compared varieties of very varying earliness, since the American results are very close to ours, although ob­tained entirely with much later varieties. In contrast, in the case of extreme botanical types of maize, greater differences have been found, particularly when a normal variety was compared with a dwarf maize (Byers and Ormiston, 1965) or with a male sterile maize (Bratzler et al., 1965; Andrieu and Demarquilly, 1974c). According to Galláis (1976), breeding of maize varieties with low lignin contents should increase the digestibility of maize.

The differences in digestibility due to environmental con­ditions (place, year, sowing date) are of much greater importance

385

TABLE 2 EFFECT OF PLACE, YEAR, VARIETY AND YIELD OF GRAIN ON ORGANIC MATTER DIGESTIBILITY OF MAIZE SILAGES (1)

Year

1970

1972

1973

Place

MONTOLDRE

CLERMONT

MONTOLDRE

CLERMONT

CHADRAT (Near Clermont)

CHANONAT (Near Clermont)

Variety

INRA 258

DEKALB 204 INRA 258

INRA 310

INRA 258 LG 11 FUNKS G 245 INRA 258 LG 11 FUNKS G 245

INRA 258 LG 11 INRA 230 INRA 240

INRA 258 FUNKS G 245 PAG 21 ADOUR 220

Dry matter content

(%)

34.1

35.9 28.2

28.5

30.9 29.4 28.3 33.8 34.0 32.6

22.2 24.4 23.4 24.5

37.7 38.3 36.7 37.6

Yield of grain

(Tonnes of DM/ha)

4.6

3.5 6.7

6.6

4.5 2.5 4.2 6.7 8.7 6.7

-

5.7 6.0 6.0 6.1 .

Organic matter digest­ibility (%)

75.0

74.4 75.1

74.2

72.1 68.7 70.2 72.2 70.6 72.1

67.1 68.3 68.4 68.9

70.5 71.5 70.3 67.3

(1) Only silages with urea and minerals

3X6

as the results with the variety INRA 258 indicate (maximum dif­ference 7.9 units ­ Table 2). The trials carried out in our laboratory (Andrieu, 1973; Andrieu and Demarquilly, 1974a), showed that maize grown in poor conditions (drought at flowering, low post­flowering temperatures, early frost) and therefore poor in grain, had reduced digestibility compared with normal maize. Thus among silages harvested more than 40 days after flowering, those with less than 55% ear (with husks) in the total dry mat­ter have a digestibility reduced by an average of 3.8 units compared with those containing at least 55% of ear (67.7%, η = 39 versus 71.5%, η = 67). The conservation quality and digest­ibility are little modified by increases in plant density (Andrieu and Demarquilly, 1974a).

INFLUENCE OF INCORPORATION OF NON­PROTEIN NITROGEN DURING SILAGE MAKING

The addition of urea during silage making, especially if it is associated with minerals, as in our trials, increases the buffering capacity of the plant so that the same maize crops, ensiled with or without minerals, differ in their fermentation characteristics (Johnson and McClure, 1968) (Table 3). However, for maize crops grown in good conditions and harvested at 25 to 35% dry matter, the addition of urea is not significant since the greater lactic fermentation which occurs is sufficient to reduce the pH to below 4.2. Butyric fermentation then remains inhibited and ammonia formation remains small (below 10% of the total Ν ­ Table 3) .

Silages containing urea have greater organic matter digest­ibility than the corresponding control silages fed without urea: 71.6 versus 68.8% in the 24 comparisons we have made. As Table 3 shows, the difference increases when the comparison is made on crops with a low crude protein content. The nitrogen con­tent of silage can thus be a factor limiting growth of micro­organisms present in the rumen and responsible for digestion (cf. also Owen, 1967). The critical level is about 8% crude pro­tein in the corrected dry matter (Andrieu and Demarquilly, 1974a).

Ammonia associated with molasses and incorporated in the same dose as urea (on the basis of nitrogen) produces maize silage

TABLE 3 .(D EFFECT OF ADDITION OF UREA AND MINERALS AT ENSILING ON THE COMPOSITION AND NUTRITIVE VALUE OF MAIZE SILAGE

Place

MONTOLDRE (3) 1970

OTHER TRIALS

No. of comparisons

6 without urea

6 with urea

18 without urea

18 with urea

Dry matter content (%)

29.5

29.5

30.6

31.4

Ash (% of DM)

5.4

6.4

5.7

6.5

Crude protein (% of DM)

4.9

10.1

8.3

12.3

Silage characteristics

pH

3.75

4.20

3.85

3.95

NH -N (% of

total N)

5.0

27.5

5.5

8.7

Lactic acid (2)

43.5

58.7

48.3

54.9

Acetic acid (2)

14.3

14.3

13.2

14.1

Butyric acid (2)

0.6

2.5

0.2

0.2

Organic matter digest­ibility (%)

64.1+3.7

70.3+1.6

70.3+2.2

71.9+2.4

(1) A solid mixture containing half urea (46% nitrogen) and half minerals was incorported at ensiling at the rate of 10 kg/tonne of forage maize.

(2) g/kg of dry matter (3) drought stricken maize

388 with fermentation characteristics and organic matter digestibility very similar to those of silage made with urea, (Demarquilly, unpublished data).

CONCLUSION: Methods of estimating the nutritive value of maize silage

The conservation quality of maize silage harvested at between 20 and 40% dry matter and then conserved without additives is generally very good, at least if the conditions necessary for successful silage making (fine chopping, rapid filling, airtight silo) are met. This is also true of silages made from normally developed maize harvested at between 25 and 35% dry matter with urea added.

The organic matter digestibility of maize silages which de­pends essentially on that of the corresponding standing crop is, on average 71.5% for normally grown maize crops, but it can vary between quite wide limits (in our study from 67.3 to 76%'when nitrogen was not a limiting factor). It is therefore important, in determining rations, to allow for these variations. There is no significant correlation between the coefficient of digest­ibility of normally developed maize (fresh or as silage) and the principal criteria of the age of the plant at harvest (dry matter content, crude fibre, percentage of ear, number of days after female flowering (Demarquilly, 1969; Andrieu and Demarquilly, 1974a). However, if only maize crops harvested more than 40 days after female flowering (which make up 95% of our silages) are considered, the correlations become highly significant especially with crude fibre content and percentage of ear, both for all sam­ples and for those with more than 8% crude protein content (Table 4) .

The coefficient of apparent digestibility of crude protein varies between quite wide limits since it depends essentially (r^ 0.95) on the crude protein content of the silage. The latter averages 8% for maize grown in good conditions but it can vary between 5 and 10% according to the date of harvest, fertilisation, environmental conditions etc.

We have not discussed here the mineral and trace element con­tent. It should be noted nevertheless that maize is poor in

TABLE 4 CORRELATION BETWEEN THE COEFFICIENT OF ORGANIC MATTER DIGESTIBILITY OF WHOLE PLANT MAIZE SILAGE AND FIRSTLY THEIR COMPOSITION AND SECONDLY THEIR DATE OF HARVEST (1)

Crude protein % DM (CP) Crude fibre % DM (CF) CP, CF. DM content CP, CF. Days (1) , CP, CF. Ear % (2) DM%, ear% Days, ear% DM%, ear%, CP, CF.

All samples (3)

No. Samp­

les (N)

122 tl

Π

II

115

ιι

II

Coeffic­

ient of correla­

tion (R)

0.032 NS (4)

0.457 HS 0.485 HS

0.500 HS

0.502 HS 0.540 HS 0.547 HS 0.541 HS

0.610 HS

Cays after flowering > 45 (1)

Ν

95 II

II

II

88 'Il

tl

H

R

0.228 NS

0.455 HS 0.456 HS

0.466 HS

0.506 HS 0.594 HS 0.601 HS 0.604 HS

0.628 HS

Days after flowering ]> 45 Crude protein > 8%

Ν

73

70

R

0.148 NS

0.507 HS 0.512 HS

O.513 HS

0.535 HS 0.543 HS 0.545 HS 0.558 HS

0.591 HS

­

Dry matter content > 27%

Ν

90

84

R

0.239 NS

0.483 HS 0.559 HS

0.586 HS

0.565 HS 0.587 HS 0.594 HS 0.593 HS

0.755 HS

Ì

Dry matter content > 27%

Crude protein >8%

Ν

66

64

R

0.114 NS

0.486 HS 0.521 HS

0.525 HS

0.529 HS 0.566 HS 0.626 HS 0.568 HS

0.688 HS

(1) Harvest date expressed as days after flowering. (2) % of ear (with husks) in harvested dry matter. (3) All samples were harvested at least 38 days after female flowering. (4) F test for the level of significance g of the simple and multiple regressions. HS = Highly Significant ­ (P < 0.001). MS = Non Significant ­o

TABLE 5 MINERAL COMPOSITION OF MAIZE SILAGE

TRIALS IN FRANCE COPPENET (1972) (Finistère) CROSSET-PERROTIN (1972) Nord-Ouest Centre-Ouest Sud-Ouest Nord-Est Centre-Est MAGNY (1962) Sud-Ouest MORRISON (1950) USA NATIONAL RESEARCH COUNCIL

Macro-elements (g/kg of DM)

Ρ

2.3

2.8 3.0 2.2 3.8 3.0

1.6-2.7

2.2

2.3

Ca

2.2

4.0 3.7 3.6 4.4 4.7

2.0-4.4

3.6

3.3

Mg

1.2

1.5 1.6 1.6 1.8 1.5

1.5-3.6

1.8

2.4

Na

0.23

0.18 0.15 0.26 0.06 0.10

0.3-0.9

0.3

0.3

Κ

11.5

15.2 13.9 13.8 14.9 13.7

9.9-16.4

-

11.5

S

1.1

1.8 1.9 1.6 1.8 1.9

3.7-2.2

1.4

1.1

Trace

Μη

37

58 69 50 51 57

26 - 93

109

50

-elements (mg/kg of DM)

Sn

26

23 22 23 27 24

-

20

Cu

4.7

6.8 5.8 6.9 6.9 6.8

2/3-12.4

4.8

10 . —.

Co

0.03

-

-

-

-

-

0.02-0.11

-

0.09

391

calcium and phosphorus and also various trace elements (partic­ularly Cu,Zn, Mn - Table 5 ) . In addition, Wiseman et al. (1938) have shown that the carotene content of maize plants diminishes rapidly with increase in the proportion of dead laminae in the plant (maturity, frost, etc.).

REFERENCES

Andrieu, J., 1973. Influence du gel à un stade de végétation précoce or de températures basses durant la phase de maturation du gras sur la compo­sition et la valeur alimentaire des ensilages de mais. Bull. Techn. CRZV. Theix - INRA, 12, 45-50

Andrieu, J., 1975. Le maïs gelé fait un ensilage de moindre qualité. Rev l'Elevage, 36, 61.

Andrieu, J. , 1976. Agronc.nic factors affecting the growth and composition of the maize plant. In: J.C. Tayler and J.M. Wilkinson (Editors). The maize crop as a basic feed for beef production. Animal Feed Science and Technology

Andrieu, J, and Demarquilly, C., 1974a. Valeur alimentaire du maïs fourrage II - Influence du stade de végétation, de la variété, du peuplement, de l'enrichissement en épis et de l'addition d'urée sur las digestibilité et l'ingestibilité de l'ensilage de maïs. Ann. Zootech., 23, 1-25. III - Influence de la composition et des caractéristiques fermentaires sur la digestibilité et l'ingestibilité des ensilage de maïs. Ann Zoo­tech. , 23, 27-43.

Andrieu, J. and Demarquilly, C.,1974b. Composition du jus de rumen chez le mouton recevant à volonté du mais fourrage sur pied ou ensilé. Ann Zoo­tech., 23, 301-312.

Andrieu, J. and Demarquilly, C. 1974c. Composition chimique, digestibilité et ingestibilité d'un maïs male-stérile sur pied et après ensilage. Ann. Zootech., 23, 423-434.

Bratzier, J.W., King, T.B. and Thomas, W.I., 1965. Nutritive value of high-sugar corn silage. J. Anim. Sci., 24, 1218 (Abstr.).

Breirem, K., 1954. Die Nettoenergie als grundlage der bewertung der Futter­mittel, in : Nehring K., 100 jähre Möckern. Die bewertung der Futter­stoffe und andere probleme der Tiernährung. Dtsh. Akad. Landwort. Berlin, t II, 97-108.

Byers, J.H. and Ormiston, E.E., 1965. Feeding value of dwarf corn silage compared with corn and hybrid corn silages. J. Dairy Sci., 48, 203-205.

3<>2

Chamberlain, C.C., Fribourg, H.A., Barth, K.M., Felts, J.H. and Anderson, D.G., 1971. Effect of maturity of corn silage at harvest on the performance of feeder heifers. J. Anim. Sci. 33, 161­166.

Coppock, C E . and Stone, J.B., 1968. Corn silage in the ration of dairy cattle: a review. Cornell Miscellaneous Bulletin 89.

Demarquilly, C , 1969. Valeur alimentaire du mais fourrage. I ­ Composition chimique et digestibilité du maïs sur pied. Ann. Zootech., 18, 17­32.

Demarquilly, C , Andrieu* J., 1973. Valeur nutritive et utilisation par les bovins de la plante entière de mais verte, ensilée ou déshydratée. Fed. Europ. Zootech., 24ème Réunion, Vienne.

Dulphy, J.P. , Demarquilly, C , Henry, M., 1975. Perte de composés volatils lors de la détermination a l'étuve de la teneur en matière sèche des ensilages. Ann. Zootech., 24, 743­756.

Gallais, Α., 1976. Vers la création de variétés de mais­fourrage. Rev. l'Elevage, 48, 37­41.

Harris, CE., 1965. The digestibility of fodder maize and maize silage. Expl. Agrie, 1, 121­123.

Hillman, D., 1969. Supplementing corn silage. J. Dairy Sci­, 52, 859­870. Johnson, R.R., McClure, K.E., 1968. Corn plant maturity. IV Effects on

digestibility of corn silage in sheep. J. Anim. Sci., 27, 535­540. Malterre, C , Lèlong, G., Haurez, Ph., 1970. Utilisation de l'ensilage

de mais pour la production de jeunes bovins. La production de viande par les jeunes bovins. Editions SEI ­ CNRA, Versailles. Etude n° 46, 253­279.

Noller, C.H., Burns, J.C. , Hill, D.L., Rhykerd, CL., Rumsey, T.S., 1965. Chemical composition of green and preserved forages and the nutritional implications. Proc. 9th Intern. Grassland Congress. Sao Paulo, 611­614.

Owen, F.G., 1967. Factors affecting nutritive value of corn and sorghum silage. J. Dairy Sci., 50, 404­416.

Wiseman, H.G., Kane, E.A., Shinn, L.A., Cary, CA. 1938. The carotene content of market hays and corn silage. J. Agrie. Res. 57, 635­669.

Animal hïcil Silence and Technology. 1(1976) 393-400 393 l-.lscvh» Scientific Publishing Company, Amsterdam - Printed in The Netherlands

MAIZE GRAIN OR EARS IN CONCENTRATE DIETS FOR YOUNG FATTENING BULLS

S. BACVANSKI Livestock Research Institute, Novi Sad, Yugoslavia.

ABSTRACT

An experiment was conducted to test the effect of partial or total substitution of ground maize grain with ground ear maize in complete mixtures for the fattening of young bulls. Animals of the control group (Group 1) received ground maize as the main ingredient of the concentrate mixture, those of Group II, ground maize and ground ear maize, and animals of Group III, ground ear maize. Increasing crude fibre in the rations by the addition of ground ear maize significantly decreased dry matter digestibility and increased digestibility of crude fibre. Bulls fed on ground maize achieved the highest daily gain which was significantly higher, by 6.62%, than that of the animals given ground ear maize, and by 3.45% compared to the ration based on ground maize and ground ear maize. Feed conversion per kg of live weight gain (LWG) was similar to daily consumption and it was higher in animals fed on the ground ear maize ration, by 16.95%, compared to those fed on ground maize, and by 8.15% compared to the animals fed on the combined ration. Both differences were statistically significant. Conversion of starch equivalent (SE) showed that the only significant difference was that between animals fed on the ground maize mixture and those fed on the ground ear maize mixture. Conversion of protein depended directly on the amount of feed consumed and the differ­ences of 99 and 57 g per kg of LWG, which were significant, could be attributed to higher consumption of the mixtures based on ground ear maize.

INTRODUCTION

The use of complete rations of high energy concentration in young fattening cattle is not in accord with the nature of digestion in ruminants, whose organs are more suited to rations

394 containing a certain amount of roughages. These concentrated rations are therefore supplemented with a roughage component such as lucerne meal or barley, but owing to the ease of technol­ogical preparation, ground ear maize is one of the most suitable sources. The aim of these investigations was to find out the effect of partial or total substitution of ground maize with ground ear maize in complete mixtures for the fattening of young bulls, on digestibility, live weight gain and feed conversion.

MATERIALS AND METHODS

For these investigations three groups were formed containing 18 young bulls of the Dutch Friesian breed which were allotted at random to the diets.

The animals received complete mixtures in which ground maize was partly or completely substituted with ground ear maize as shown in Table 1. TABLE 1 COMPLETE MIXTURES AND THEIR CHEMICAL COMPOSITION (%)

Ingredient Ground maize Ground ear maize Dry sugar beet pulp Sunflower oil meal Urea Salt Ground limestone Premix

Chemical composition Dry matter Crude protein Crude fat Crude fibre N-free extractives

T r e a t m e n I

83.5 -5 7 1.5 1 1 1

84.67 14.25 3.92 4.34 62.30

II

35.5 46.0 5 9 1.5 1 1 1

86.22 14.29 3.27 8.09 60.16

t III

-79.5 5 11 1.5 L 1 1

87.13 14.46 2.83 10.86 58.41

395 The animals of Group I were fed on a complete ration based on

ground maize as a source of energy. In treatment II ground maize was partly substituted with ground ear maize, while the animals of Group III were fed on a mixture based on ground ear maize as the energy source. In all three mixtures urea was the basic protein component and sunflower oil meal was included in these mixtures to equalise the level of protein in the diets. The level of energy in these mixtures was unequal and it decreased in relation to the level of substitution of ground maize by ground ear maize. The animals were individually fed ad libitum and water was available from automatic water bowls.

A digestibility trial was carried out using three represent­ative animals of each group weighing about 300 kg. Digestibility coefficients of the individual nutrients were used to obtain conversion of energy and protein. Data for the digestibility of the rations, live weight gains, conversion of feeds and nutrients were processed by analysis of variance as suggested by Snedecor (1965).

RESULTS OF INVESTIGATION AND DISCUSSION

Digestibility of rations Coefficients of digestibility are presented in Table 2.

TABLE 2 COEFFICIENTS OF DIGESTIBILITY (%)

Dry matter Crude Crude Crude

protein fat fibre

N-free extractives

Τ r I

81 79 76 33 88

88 53 47 46 54

e a t m e η t II

76 78 70 47 83

46** 47 36 64 (59***

III

76 78 63 54 82

30** 05 70* 93* 45***

* =(Ρ <0.05) ** = (Ρ<0.01) *** = (Ρ <0.001)

The ration based on ground grain (treatment I) had the highest digestibility coefficients of all nutrients except crude

3% fibre, while they were the lowest in the mixture where ground maize was completely substituted with ground ear maize. Digestibility of dry matter, crude fat and N-free extractives was significantly higher in animals fed on the mixture of grain and ground ear maize than in those given ground ear maize alone. Although the digestibility coefficient of crude protein was the highest in the animals fed on ground maize, differences between treatments were not statistically significant. On the basis of these data it may be supposed that in well balanced mixtures the content of energy affects dry matter digestibility. Other workers (Putnam et al. 1966; White et al. 1971; Bacvanski et al. 1972; Vucetic et al. 1972; Obraõevic et al. 1972) have also shown that dry matter digestibility increases with higher amounts of concentrates in diets for fattening young cattle. Coefficients of crude fat digestibility depended on its content in the ration and the level of fibre, which is in agreement with the results of McCroskey et al. (1961), Richardson et al. (1961) and Bacvanski et al. (1974), who concluded that an increase of crude fibre in the ration decreased the digestibility of crude fat. In crude fibre there was a reverse tendency, i.e. digestibility was increased with higher content of ground ear maize, similar to results obtained by Cobió et al. (1974) and others.

On the basis of these digestibility coefficients it was found that 1 kg of the complete mixture of Group I contained 0.73 SE, Group II 0.69 SE and Group III 0.68 SE. The energy value of the mixture used in Group I was higher by 5.64% and 7.04% compared to those of Groups II and III respectively, while the difference between mixtures II and III was small (1.32%). There was no big difference in digestible crude protein since its content in the mixtures amounted to 11.33%, 11.21% and 11.29% in the three diets respectively. The results obtained show that partial or total substitution of ground maize with ground ear maize decreases digestibility of the complete mixtures and lowers the energy content of feeds. Weights and_ga_ins

Average weights and gains as well as the duration of fattening are presented in Table 3.

Although there was an initial difference in average live weight of animals of 7.11 kg, statistical analysis showed that

397

it was not significant. Thus there was no influence of initial weight on the results of fattening.

TABLE 3 AVERAGE LIVE WEIGHT, TOTAL AND DAILY GAIN(kg)

Number of animals Average Initial weight Average final weight Total gain Number of feeding days Average daily gain

Difference III II

T r e I

18 159.22 454.56 295.34 229.12 1.29

0.08** 0.04

ns

a t m e η t II

18 155.89 444.50 288.61 231.63 1.25

0.04ns

III

18 152.11 443.06 290.95 240.65 1.21

** = (Ρ <0.01) n s = not significant

Animals fed on the mixture containing ground maize (Group I) achieved the highest average daily gain of 1.29 kg which was higher than that of Group II, (ground maize and ground ear maize) by 6.62%, and higher than that of Group III (ground ear maize) by 3.45%. The result obtained comparing Groups I and III is highly statistically significant (P <0.01) and it may be concluded that the sources of energy in the ration had an effect on live weight gains. The study of Zeremski et al. (1972) showed that animals fed on mixtures containing ground maize achieved higher gains in relation to those fed with different ratios of ground maize and ground ear maize by 1.83 and 7.30% respectively. Milosevic et al. (1973) found a non significant increase in gains by a group of young cattle fed on a mixture containing 60% of ground ear maize compared to that consuming a mixture with 56.25% of ground maize. Comparing complete mixtures on the basis of ground maize and ground ear maize, Davis et al. (1963) , Vucetic et al. (1972) and Bacvanski et al. (1974) obtained higher gains using mixtures with ground maize

398 but the differences were not significant.

On the basis of these results it may be concluded that use of ground ear maize in the mixtures decreases the energy value of the ration and average daily gains. If the percentage of ground ear maize is low, about 50%, the gain will depend on the compo­sition of other ingredients and on the energy value of the total ration. Conversion of feeds and nutrients

These data are presented in Table 4. The highest average daily consumption was in animals which received the ration with ground ear maize as the main source of energy. This consumption was higher than that in animals consuming the mixture with ground maize by 9.73%, and in relation to the combined ration (Group II) it was higher by 4.8%. Increased consumption of rations contain­ing ground ear maize is probably a result of preference given to rations with ear maize due to the roughage present in it. Feed conversion per kg of live weight gain was higher in Group III in relation to Groups I and II by 16.95 and 8.15% respect­ively. The difference between Groups III and I of 892 g was highly significant (P <_0.001) while the differences between Groups I and II (428 g) and between Groups II and III (464 g) were also significant (P <0.05). Davis et al. (1963), Williams et al. (1968) , Vuãetic et al. (1972) , Bacvanski et al. (1974) and others showed that substitution of ground maize with ground ear maize increases consumption and conversion of feed, which is in agreement with the results of this experiment. TABLE 4 DAILY CONSUMPTION OF FEEDS AND NUTRIENTS ( kg)

Concentrate mixture Per kg of LWG

Starch equivalent Per kg of LWG

Digestible crude protein Per kg of LWG

Dry matter Per 100 kg of live weight

Ration concentration (%)

T r e a t m e n I

6.79 5.26** 4.95 3.84 0.77 0.60 5.77 1.88

86.19

II 7.09 5.69** 4.90 3.93 0.79 0.64* 6.11 2.07 80.10

t III 7.44 6.16*** 5.07 4.20* 0.84 0.69*** 6.48 2.18 78.23

* = (P <0.05) (P <0.01 *** = (P <0.001)

399 Differences in conversion of starch equivalent were not so

prominent since they appeared between animals fed on ground maize and ground ear maize (P <0.05), amounting to 9.21% in favour of the ground ear maize diet. Animals of Group III con­sumed 6.74% more SE per kg of LWG compared to those of Group II, while the difference between Groups II and I amounted to only 2.3%. Conversion of protein depended directly on the amount of feed consumed, because all mixtures were isonitrogenous. Animals fed on the diet based on ground ear maize consumed 16.61% more protein per kg of LWG than those which received the diet based on the ground maize, and 8.93% more protein compared to the animals consuming the mixed diet. (Group II). Both of these differences were statistically significant (Table 4). Dry matter consumption per 100 kg of live weight showed a tendency to decrease with higher ration concentration, which means that fattening cattle consume less dry matter per 100 g of live weight if the ration concentration is higher.

REFERENCES

Bacvanski, S., Cobié, T., Vucetic", Sof ija, 1972. Maize, corn and cob meal and dry sugar beet pulp as the energy sources in the whole concentrate rations for fattening of bulls. Review of Research Work, 5, Livestock Research Institute, Novi Sad.

BaSvanski, S., Vucetid,Sofija, dobic, T. 1974. Corn and cob meal in complete mixtures for fattening of cattle. Journal for Scientific Agricultural Research, XXVII, No.98, Belgrade.

Cobic", T., Bacvanski, S., Vucetic", Sof i ja, 1974. Evaluation of ground maize and cob meal as a source of energy in fattening young cattle using isonitrogenous rations. Contemporary Agriculture, XXII, 11-12, Novi Sad.

Davis, R.E., Oltjen, R.R., Bond, James, 1963. High concentrate studies with beef cattle. Journal of Animal Science, 22, 640.

McCroskey, J.E., Pope, L.S., Stephens, D.F. and Weiler, G. 196]. Effect of pelleting steer fattening rations of different concentrate to roughage ratios. Journal of Animal Science, 20, 42.

Miloäevi<5, M. , Bacvanski, S. , Coble, T., Vucetic", Sofija and Vlcek, B. 1973. Preservation of high moisture corn by propionic acid and its value in feeding of beef cattle. Science in Practice, 3, 2, Belgrade.

400

Obraíevic C , Bacvanski, S., Cobió, T. and Vuòetió, Sof ija, 1972. Feed conversion with varying ratios of concentrates to alfalfa meal in fattening young bulls. Journal for Scientific Agricultural Research XXV, No.92, Belgrade.

Putnam, P.A., Elam, C.J., Davis, R.E. and Wiltbank, J.N. 1966. Dietary energy and protein effects on rumen volatile acids and ration digestibility by beef heifers. Journal of Animal Science, 25, 988.

Richardson, D., Smith, E.F., Baker, F.H. and Cox, R.F. 1961. Effects of roughage-concentrate ratio in cattle fattening rations on grains feed efficiency, digestion and carcass. Journal of Animal Science, 20, 316.

Snedecor, W.G. 1965 Statistical Methods, Ames, Iowa. Vucetic. Sofi ja, Bacvanski, S. and Cobic T. 1972. Effect of level and source

of energy in fattening of young bulls fed with rations containing urea. Review of Research Work, 6, Livestock Research Institute, Novi Sad.

White, T.W., Reynolds, W.L. and Hembry, F.G. 1971. Digestibility of finishing rations containing various sources and levels of roughage by steers. Journal of Animal Science, 32, 544.

Williams, D.B., Bradley, N.W., Little, CO. and Crowe, W.M. 1968. Effects of oyster shell with and without roughage in beef finishing rations. Journal of Animal Science, 27, 299.

Zeremski, D. , Koljajici, V. and Ilia V. 1972. Effect of replacing ground corn by corn and cob meal and sunflower oil meal by urea on the results of fattening young bulls entirely with concentrates. Journal for Scientific Agricultural Research, XXV, 92, Belgrade.

Animal Feed Science and Technology. 1 (1976) 401-415 401 IINevier Sdentila· Publishing Company. Amsterdam - Printed in The Netherlands

RATE OF GROWTH, FEED UTILISATION AND DIGESTIBILITY OBSERVED WITH DIETS CONTAINING ENSILED MAIZE GRAIN OR MAIZE EARS FED ALONE OR IN MIXTURES

D. LANARI and M. RIONI Istituto di Zootecnica, università di Padova, Italy

ABSTRACT

Rate of gain of beef cattle fed ensiled high moisture maize ears or grain in high concentrate diets gave values comparable to those observed with dry products while feed conversion was improved by the introduction of ensiled products.

Digestibility was higher with ensiled products than with cor­responding dry concentrates especially when maize ears have been considered. Dry matter content at harvesting was shown to be important in affecting digestibility since, from the experiments discussed, it does not seem advisable to ensile products with more than 70% dry matter.

Animal performance with mixed diets was affected by the level of maize silage in the diet. The best results were achieved when maize silage comprised up to 55% of the diet dry matter.

Experiments on voluntary intake of mixed diets have shown that the highest dry matter intake is reached when maize silage re­presents roughly 50% of the total ration dry matter.

Nutrient digestibility of mixed diets of corn silage and con­centrates increases as concentrate level increases.

INTRODUCTION

During recent years, the use of ensiled high moisture maize grain or ears has become more and more common in beef cattle feed­ing. The growing cost of drying and the complete mechanisation of most of the harvesting and ensiling processes are the most probable causes of this trend. Nevertheless, several points need further clarification; they include not only the choice of the best moment for harvesting in order to produce the highest util­isation of nutrients, but also the study of the use of these feeds

402

alone or in combination with dry or ensiled forages in rations for beef production. In this paper we will present and discuss some of the more recent results on these topics.

UTILISATION OF ENSILED MAIZE GRAIN AND MAIZE EARS, IN HIGH CON­CENTRATE RATIONS FOR BEEF CATTLE

The literature on this topic does not appear particularly rich. Some of the more significant experiments conducted by different authors using ensiled maize grain or ears in high concentrate rations are reported in Tables land 2. Most of the data have been collected from fattening trials on bulls and only in one experiment (Forsyth et al., 1972) were steers utilised.

If we consider data from trials where dry or ensiled ears have been compared, no difference among treatments can be noted in growth rate. On the contrary, dry matter intake shows a reduction with ensiled ears, so that feed conversion appears significantly improved in comparison with dry ears. Klostermann et al. (1960) obtained comparable results, more than ten years ago, feeding similar rations to steers.

The positive effect on feed utilisation, observed as a result of ensiling high moisture maize ears, has been noted by Forsyth et al. (1972) and Tonroy et al. (1974) also with high moisture, acid-treated grain in comparison with dry corn grain.

Moreover, Tonroy et al. (1974) observed that reconstituting and ensiling dry corn does not allow the same improvements to be made in feed conversion which are observed with corn harvested at a high moisture content and ensiled.

A particular comment has to be made on the data of the second experiment summarised in Table 2. The values reported show that steaming and rolling maize grain is of great advantage for sup­porting a high growth rate, producing a very low feed conversion ratio. At the same time, no significant difference resulted be­tween ensiled maize grain and ensiled ears, suggesting that ensiled ears have a nutritive value not far from that of grain.

Since the experiments reported appear sufficiently similar in many parameters such as initial and final live weight, daily gains and ration composition, it is possible to make some useful comparisons among them.

TABLE 1 DAILY GAINS, VOLUNTARY INTAKE AND FEED UTILISATION OBSERVED WITH MAIZE EARS DRY OR ENSILED

Number of animals Initial live weight Final live weight Daily gain

Daily dry matter intake Forage Protein supplement Maize

Total daily DM intake Dry matter intake/gain

kg fl

II

II

II

II

II

II

Maize ears dry (Rioni and

16 250.8 435.6 1.36

0.88+

0.43 6.65 7.96 5.85«

Maize ears ensiled

Chiericato, 1972)

16 251.4 435.4 1.35

0.88+

0.45 6.30 7.63 5.65fc

Maize ears dry

(Giardini and

20 231.5 411.5 1.35

0.35++ 0.90 6.51 7.76 5.76a

Maize ears ensiled

Vecchiettini, 1975)

20 230.0 421.0 1.40

0.43++

0.90 5.92 7.25 5.16*

Means within the same row with different superscripts are significantly different (P<0.05) + = hay ++= maize silage, milk stage

TABLE 2 DAILY GAINS, VOLUNTARY INTAKE AND FEED UTILISATION OBSERVED WITH MAIZE GRAIN, DRY, STEAMED AND ROLLED OR ENSILED

Number of animals Initial live weight kg Final live weight " Daily gain "

Daily dry matter intake Forage " Protein supplement " Maize "

Total daily DM intake " Dry matter intake/gain "

Maize grain dry

(Forsyth

6 244 431

1.33

0.75+

0.75 5.98 7.48'^' 5.62

fc

Maize grain ensiled et a ] . , 1972)

6 271 475

1.46

0.78+

0.78 6.22 7.78^ 5.33<

îl

Maize grain ac. treated

6 251 448

1.41

0.72+

0.72 5.80 7.24

a¿

5.13ai

Maize grain steam­rolled

Maize grain ensiled

(Bonsembiante et al..

20 258.6 435.8

1.49'

0.96++

0.86 5.69 7.52 5.04

a

20 259.2 423.3

1. 3βαί

0.96++

0.86 5.73 7.55 S.47ab

Maize ears ensiled

1974)

20 259.4 418.8

1.34a

0.96++

0.86 6.22 8.04 6.00^

Means within the same row with different superscripts are significantly different (Ρ (0.05) + = ground hay mixed with concentrates ++= hay

405 From the results, two conclusions can be made: first,

ensiled maize grain or ensiled ears in high concentrate rations support a growth rate similar to that observed with dry products. Second, the use of ensiled high­moisture ears or grain allows a certain improvement in feed utilisation. This advantage was noted also in research on dairy cows, (Zogg et al., 1961; McCaffree and Merrill, 1968).

Now, if we consider experiments where digestion trials have been performed we can find some explanation of these results. Klostermann et al. (1960), McCaffree and Merrill (1968) and Bonsembiante et al. (1974), working on corn ears noted that digestibility was higher in ensiled ears than in the dry product. This can be explained by the reduction in cob digestibility that takes place with advancing maturity, as was shown by Thornton et al. (1969). Not so clear is the relationship between digest­ibility and feed utilisation with ensiled maize grain, since some authors (Polzin et al., 1972; Clark et al., 1973) did not note an improvement in utilisation of high­moisture corn in comparison to dry corn. On the other hand, in many other experiments (McCaffree and Merrill, 1968; Clark and Harshbarger, 1972; McKnight et al., 1973; Tonroy et al., 1974) some improvement in the digestibility of ensiled grain was observed.

TABLE 3 EFFECT OF DRY MATTER CONTENT ON MAIZE GRAIN DIGESTIBILITY

Dry matter content (%)

Digestion coefficients (%) Dry matter Organic matter Crude protein Energy

Ensiled grain

75

77. Ob

78. lb

67.3afc

75.0*

Propionic and acetic acid treat­ed grain

75

77.4fc

78.5* 67.3

tó

■75.3*

Propionic acid treated grain

75

77. lh

78.9b

68. Sb

75.9b

Dry grain

89

74.2a

75.4a

64.1a

72.4a

Means within the same row with different superscripts are significantly different (P <0.05) . Reference: McKnight et al. (1973).

406

In Table 3 are given the results reported by McKnight et al. (1973), where the superiority of grain harvested at high­moisture content and ensiled or acid treated, in comparison with dry grain, appears clearly. According to this author, the higher digest­ibility of grain harvested at high moisture content, to whatever treatment it was subjected, could be at least partially explained by its slower rate of passage through the rumen. From the liter­ature examined, we can draw the conclusion that ensiled ears are better ulitised than dry ears and that there is a similar trend also for ensiled grain. Now we can consider whether there is a moisture level at harvesting which represents the optimum for feed utilisation. In Table 4 are reported data of a trial that we have recently carried out in Padua and whose results have not yet been published. We have been led to conduct this research from an examination of the different performance obtained with beef bulls by Rioni and Chiericato (1971) and by Bonsembiante et al. (1974) with ensiled maize ears of different moisture con­tent.

Maize ears and grain, used in the digestion trial, came from the same field and cultivar; the ears were hand picked and the grain was harvested with a combine.

Both products were ground through a hammer mill and then ensiled in plastic silos of roughly two tons capacity. The digestion trial was performed on bulls according to a 4 χ 4 Latin square design.

As can be seen from Table 4, an increase of 10 points in dry matter content of maize ears produced a significant (P<0.05) reduction of roughly five points in nutrient digestibility.

A similar reduction was observed with maize grain, but the difference reached statistical significance only for energy. Digestion coefficients observed in ensiled grain were signifi­cantly higher than in ensiled ears.

From the results of our experiments, it appears of great importance to check dry matter content of both maize ears and grain before harvesting for ensiling. DM level should not be higher than 70% in order to maximise feed utilisation for beef production. When this level is exceeded and at a level close to 80%, digestibility decreases and little fermentation can occur during storage in silos.

407 TABLE 4 EFFECT OF DRY MATTER CONTENT AT HARVESTING ON THE DIGESTIBILITY OF ENSILED MAIZE GRAIN AND MAIZE EARS

Dry matter content (%)

Digestion coefficients (%) Dry matter Organic matter Crude protein NFE Energy

Maize ears ensiled

68

7 5 . 9A*

7 7 . 0 ^ 56.4

a

ABb 83.7 ΠΑ AAb

74.4

79

70.6A a

12.0Aa

51.6a

78 y α

69 y α

Maize ens i

70

87.6B e

88.5ß C

72.2 91.8

C C

86.5ß d

grain led 79

83.6** 85.0

B C

62.3b

89.0S C C

82.4B C

Means within the same row with different superscripts are significantly different (α­b Ρ <0.05) {Α­B Ρ <p.01) . Reference: Rioni and Lanari (1976). UTILISATION OF MAIZE GRAIN AND ΓΆΙΖΕ EARS IN ΠΧΕΌ DIETS WITH WHOLE­CROP­ΓΆΙΖΕ SILAGE

In Table 5, the results of some trials performed in Italy on fattening bulls with diets containing different ratios of maize silage and concentrates are summarised. In the first experiment (Giardini, 1970), three diets with increasing pro­portions of the "forage were compared.

Daily gain decreased significantly (P<.0.05) from 1.46 kg to 1.24 kg when percent of dry matter from concentrate was reduced from 90 to 70%. Total dry matter intake increased but feed utilisation worsened with increasing forage content and, because of the low quality of the forage used (maize stover and maize silage at the milk stage), no reduction was noted in the amount of dry matter from concentrate consumed per kg gain. In this case, forage utilisation was very limited and no advantage was derived from its introduction in the diet.

In the second experiment, steamed and rolled maize grain was fed ad libitum in the first treatment, while in the second the ration contained 1/3 maize grain steamed and rolled and 2/3 maize silage.

Finally, in the last treatment, animals were fed only maize silage to 350 kg live weight. Thereafter the silage was reduced

TABLE 5 DAILY GAINS, VOLUNTARY INTAKE AND FEED UTILISATION OBSERVED WITH YOUNG BULLS FED DIETS WITH DIFFERENT RATIOS OF MAIZE SILAGE AND CONCENTRATES.

Diet dry matter Maize silage (%) composition Concentrate (%)

Number of animals Initial live weight kg Final live weight " Daily gain " Daily dry matter intake

Forage " Protein supplement " Concentrate "

Total dry matter intake " Dry matter intake (kg)/kg gain Concentrate dry matter (kg)/kg gain

10 90

20 80

30 70

(Giardini, A., 1970)

48 250.0 400.9 1.41

a

0.81 ­

7.30+

8.11 5.76

a

5.21

48 250.0 400.1 1.34

fo

1.77 ­

7.08+

8.85 6.61« 5.28

48 250.0 401.2 1.20^

2.73 ­

6.36+

9.09 7.57'

c

5.30

0 100

45 55

Bonsembiante et a

12 244.9 417.6

1.23W'

­

0.76 5.15" 5.91a 4.82^ 4.82

12 248.3 418.8 1.19

ft'

3.37 0.94 3.04" 7.35« 6.18« 3.34

571

43 1.(1970)

12 249.7 420.5 0.98^

3.93 1.09 1.76" 6.78 ' 6.92

C

2.90

63 37

Giardini Vecchiett

20 231.5 424.0 1.33

4.92 O.90 1.93" 7.75 5.82 2.12

65 35

and ini, 1975)

20 228.0 4 30.0 1.33

4.66 0.90 1.63" 7.19 5.42 1.90

Means within the same row with different superscripts are significantly different {ab P<0.05) (.AH Ρ <0.01) + , ­ .·

, = see text I Average data from two periods ­ first 250­350 kg live weight animals were fed corn silage and protein

supplement; second from 350 kg to slaughter animals were fed grain silage.

409

to 6 kg per day and maize grain, steamed and rolled, was given in increasing amounts.

Daily gains were reduced with the introduction of maize sil­age, but the decrease was not so great if we consider the.treat­ment where the mixed diet was employed. Dry matter intake in­creased with the presence of maize silage, reaching the highest value with the mixed ration where roughly half of the dry matter was derived from concentrates.

Feed conversion worsened with increasing silage intake but it is important to underline that, at the same time, concentrate intake per unit of gain decreased from 4.8 kg to 2.9 kg.

In the last trial reported, maize silage represented over 60% of the diet dry matter; as an energy supplement, dry maize grain or ensiled high­moisture grain were used. Daily gains were the same with both diets, but dry matter intake was slightly re­duced with ensiled maize. Concentrate consumption per kg gain was very low with both diets.

From an overall impression of these trials, forage quality seems to play an important part if a reduction in concentrate use is sought. Moreover, forage has to represent more than 30% of the diet dry matter in order to get good forage utilisation. Finally, it does not appear convenient to divide fattening per­iods into sub­periods with striking differences in ration compo­sition when the rearing period is rather short (150 ­ 180 days).

Since it was observed that, with mixed diets, dry matter in­take and animal performance can vary greatly, depending on for­age quality and concentrate : forage ratio, an intake and digestion trial was performed in Padua using five mixed diets obtained from maize silage and ensiled maize ears given in different ratios and supplemented with protein, vitamins and mineral salts. For this trial, young bulls were used in a 5 χ 5 Latin square design.

The results of the intake experiment are represented in Fig. 1, while the corresponding data are reported in Table 6. The parabolic trend of the curve shows that the highest intake was obtained with the diet where half the dry matter came from maize silage and half from ensiled maize ears. Digestible energy in­take too was higher with this diet. The intake observed with the 100% maize ear silage ration, was significantly (P< 0.05) lower than with all other treatments. A study of the diet

410

2.3

2.2­σι

ã ì> 2.1

σι i¿ 2.0 o o

1.9­

Û 1.8 σι

0 100

25 75

50 50

75 100 % maize ears silage 25 0 % maize silage

Diet dry mat t e r composi t ion Figure 1 DRY MATTER INTAKE OF YOUNG BULLS FED MIXED DIETS OF MAIZE SILAGE

AND MAIZE EAR SILAGE y = 2.1154 + 0.0068x ­ O.000097x2 SDres. = 0.1743 where χ = % DM from ear silage

80 >. ■t: 7 0

­Q

w 60 ω 03

­D 5 0

■*­/

S 40 ί _

ra & 3 0 ro

# 20

• O

Π

■

o 100

25 75

50 50

Diet dry matter composition

75 100 % maize ear silage 25 0 % maize silage

Figure 2 EFFECT OF INCREASING LEVELS OF MAIZE EAR SILAGE ON NUTRIENT DIGESTIBILITY

organic matter O energy G crude fibre crude protein

411

characteristics which could explain the observed trend in intake, has included consideration of % dry matter, % lactic acid, % acetic acid, energy concentration in digestible energy (DE) , pH and % DE of the ration.

The statistical calculations made between daily dry matter consumption and the above listed variables have shown that feed intake appears to be particularly conditioned by digestible energy content of the diet and by the metabolic live weight as reported by Baumgardt (1970). Such phenomena can be expressed by the following equation:

y =­219.76 + 146.76x ­ 23.68x2 + 0.0162z Residual SE = 0.711 where y = Daily dry matter intake, kg,

χ = DE,Kcal/g DM, ζ = LW, kg ° ·

7 5

Such a result does not seem easy to interpret. Probably in the diets in which the proportion of the ensiled maize repres­ented more than 50% of the total dry matter, the prevailing ele­ments in feed intake regulation seem to be connected to diet volume and to the longer time of retention of silage residues in the digestive tract, as was observed by Campling (1966) working on hay and silages.

When the proportion of dry matter from ensiled maize ears was higher than 50%, the decrease in consumption of dry matter and of digestible energy, can be explained by a low rumen pH and high VFA concentration (Baumgardt, 1970). Moreover an effect due to diet palatability cannot be excluded.

Considering the digestibility of mixed diets (Table 6 ) , the data indicate a progressive and linear rise in digestibility of organic matter and of energy as the proportion of ensiled maize ears in the diet increased. Digestibility of protein too, al­though showing a less regular trend than the other components, rose with an increase in the proportion of maize ears in the diet (Fig. 2).

Crude fibre digestibility had an opposite trend since it de­creased with increasing content of maize ears in the diet. This

TABLE 6 DRY MATTER CONSUMPTION AND APPARENT DIGESTIBILITY OF MAIZE SILAGE AND MAIZE EARS SILAGE MIXED DIETS (Lanari, 1976)

Diet dry ) Maize ear silage (1) matter ) composition ) Maize silage (.%)

Voluntary intake DM/lOO kg live weight (kg)

Digestion coefficients (î,) Organic matter Crude protein Crude fibre Energy

0

100

2ΛΑΑΒΟ

69.2'?t·'

48.5¿'B

58.9^ 66.3

6*ΰ

25

75

2.16­4''*

72 3 C'RC

5 1 . 2 ^ 54 . l1^'' 69. 2ÍJC'IÍ

50

50

2.25;Γ*

74.0^* 48.ΦΒ

ΛΑ.\',ΑΒ

ΊΟ.Φ AB

75

25

2.09­'lßi'

74.6M S

si.d'B

31.3r"ß

71.6^ö

loo 0

l.82'1a

78.9a/!

62.3^ 16. 9 ^ 76.6

a71

Means within the same row with different superscripts are significantly different (ah Ρ 0.05) (/IΛ Ρ <0.01)

413

phenomenon, already pointed out by other authors in relation to high concentrate diets (Bonsembiante et al., 1969) can be ex­plained in terms of rumen liquor characteristics which are not favourable to cellulolytic bacteria.

The linear trend of the diets studied seems to exclude inter­action effects between the two principal dietary components.

Similar conclusions have been reached by Preston (1975) with diets similar to the ones we used and by Kroman et al., (1975) with diets of alfalfa hay and dry maize grain.

From the results discussed in this paper, it can be concluded that ensiling high moisture maize ears or grain is an advantageous technique; it allows us to eliminate the cost of drying, producing a concentrate which is used by fattening animals more efficiently than the corresponding dry products with no influence on daily gains. This can be at least explained by a better digestibility of these high moisture products. Moreover, moisture level at harvesting plays a well defined and important role since it does not seem advisable to harvest ears or grain for ensiling with a moisture level lower than 30 - 33%.

From the experiments on mixed diets where maize silage is the forage component, it appears that the best results in terms of animal performance, feed intake and digestible energy intake, are achieved when roughly 45 - 55% of the dietary dry matter comprises maize silage and the remaining part is from concentrates.

REFERENCES

Baumgardt, B.R., 1970. Control of feed intake in the regulation of energy balance. Physiology of digestion and metabolism in the ruminant. Ed. A.T. Phillipson. Oriel Press, Newcastle upon Tyne.

Bonsembiante, M., Rioni, M., Chiericato. G.M., 1970. Contributo sperimentale sulla produzione del vitellone in rapporto alla dieta, al sistema di stabulazione ed al tipo ristallo. Alimentazione Animale, XIV, 5, 33.

Bonsembiante, M., Rioni, M., Lanari, D., 1969. L'effetto della vapor­izzazione e rullatura del mais e della presenza di fieno e di insilato sulle caratteristiche del liquido di rumine e sulle "performances" del vitellone. Alimentazione Animale, XIII, 5, 351.

Bonsembiante, M., Rioni, M., Parigi-Bini, R., Chiericato, G.M., 1974. Ricerche sui pastoni di mais nella produzione del vitellone. Rivista di Zootecnia e Veterinaria, 2, 97.

414

Campling, R.C., 1966. The intake of hay and silage by cows. Journal of the British Grassland Society, 21, 41.

Clark, J.H., Frobish, R.A., Harshbarger, K.E., Derrig, R.G., 1973. Feeding value of dry corn, ensiled high moisture corn and propionic acid treated high moisture corn fed with hay or haylage for lactating dairy cows. Journal of Dairy Science, 56, 1531.

Clark,J.H.,Harshbarger, K.E., 1972. High moisture corn versus dry corn in combination with either corn silage or hay for lactating cows. Journal of Dairy Science, 55, 1474.

Forsyth, J.G., Mowat, D.N., Stone, J.B., 1972. Feeding value for beef and dairy cattle of high moisture corn preserved with propionic acid. Canadian Journal of Animal Science, 52, 73.

Giardini, Α., 1970. Stabulazione e livelli alimentari nell'allevamento del vitellone. Alimentazione Animale, XIV, 3, 11.

Giardini, Α., Vecchiettini, M., 1975. I cereali foraggeri nell'allevamento del bovino da carne. Informatore Agrario, XXXI, 18353.

Klostermann, E.W., Johnson, R.R., Scott, H.W., Moxon, A.L., Van Stavern, J., 1960. Whole plant and ground ear corn silages, their acid content, feeding value and digestibility. Journal of Animal Science, 19, 522.

Kroman, R.P., Clemens, E.T., Ray, E.E., 1975. Digestible, metabolisable and net energy value of corn grain and dehydrated alfalfa in sheep. Journal of Animal Science, 41, 1752.

Lanari, D., 1976. L'effetto di diete contenenti rapporti diversi di mais ceroso e pastone di pannocchia sulla digeribilità delle sostanze nutri­tive e sulla ingestione volontaria di alimenti. In course of publication.

McCaffree, J.D., Merrill, W.G., 1968. High moisture corn for dairy cows in early lactation. Journal of Dairy Science, 51, 553

McKnight, D.R., Macleod, G.K., Buchanan­Smith, J.G., Mowat, D.M., 1973. Utilisation of ensiled or acid treated high moisture shelled corn by cattle. Canadian Journal of Animal Science, 53, 491

Polzin, H.W., Otterby, D.E., Murphy, J.M., Johnson, D.G., 1972. Utilisation of ensiled, acid­treated and dry corn by lambs. Journal of Animal Science, 35, 1133 (Abst.)

Preston, R.L., 1975. Net energy evaluation of cattle finishing rations con­taining varying proportions of corn grain and corn silage. Journal of Animal Science, 41, 622.

Rioni Volpato M., Chiericato, G.M., 1972. Impiego del "pastone di pannocchia" della pannocchia secca di mais e del fieno di erba medica e di loietto nella produzione del vitellone. Alimentazione Animale, XVI, 2, 25.

415

Rioni, M., Lanari, D-, 1976. Perdite di insilamento e digeribilità di pas­toni di granella e di pannocchia raccolti a differente contenuto di umidità. In course of publication.

Thornton, J.H., Goodrich, R.D., Meiske, J.C., 1969. Corn maturity. III. Composition, digestibility of nutrients and energy value of corn cobs and ear corn of four maturities. Journal of Animal Science, 29, 987.

Tonroy, B.R., Perry, T.W., Beeson, W.M., 1974. Dry, ensiled high-moisture-ensiled reconstituted high moisture and volatile fatty acid treated high moisture corn for growing-finishing beef cattle. Journal of Animal Science, 39, 931.

Zogg, C.A., Brown, R.E., Harshbarger, K.E., Kendall, K.A., 1961. Nutritive value of high moisture corn when fed with various silages to lactating dairy cows. Journal of Dairy Science, 44, 483.

Animal Feed Science and Technology. 1 (1976) 417-427 4 1 7 Ulsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands

UTILISING THE MAIZE CROP IN VARIOUS FORMS FOR BEEF PRODUCTION

C. MALTERRE Institut National de la Recherche Agronomique, Centre de Recherches Zootechniques et Vétérinaires Theix, 63110 Beaumont, France. and C. LELONG Institut Technique des Céréales et des Fourrages, Station Expérimentale de Boigneville, 91720 Maisse, France.

ABSTRACT

Whole crop maize silage is well suited to the fattening of bulls when supplemented with concentrates (850 - 950 g total crude protein per day for dairy breed bulls between 270 and 650 kg), minerals and vitamins.

Supplements of hay are not essential but 1 kg good lucerne or grass hay could slightly improve growth rate. Urea can supply all the nitrogen supplement for animals over 200 kg: in this case, animal performance decreases (by 9 - 10%); it is wiser to add 4 - 500 g to the maize silage plus urea, to limit the decline in performance.

For early maturing breeds, cereal supplements are not neces­sary, except during the last 2 or 3 months to improve the carcass and are mainly needed with low dry matter silages. For late maturing breeds, energy supplementation of maize silage is followed by slight improvement in growth rate, feed efficiency and carcass quality:

The rate of substitution of silage by concentrate was found to be higher with moist cereals than with dried cereals and with high dry matter silage than with low dry matter silage.

There was no difference in feed efficiency between ground dried grain and moist grain (either crushed and ensiled, or stored after propionic acid treatment and rolled) when maize grain amounted to 35 or 40% of DM intake. On the other hand, dried or moist maize grain had a much better utilisation when crushed before being fed to the animals. Maize ears dried or ensiled can replace maize grain as supplements to whole crop silage.

418 Maize ears of grain can be fed as the basis of a diet,

to which grain,some straw (0.5 to 1 kg per day) or hay ( 1 - 2 kg per day) is added. The growth rate is higher with ensiled ears and grain diets than with whole crop diets; feed efficiency is better for diets of ensiled ears (by 16% on average) and for moist grain diets (by 18.5% on average) than for the whole crop diets. Storage method for maize grain when grain is given ad libitum did not seem to have an effect on the growth rate, but feed efficiency is better with moist grain (by 10- 12%) than with dried grain and with ground grain than with whole grain (especially in the case of propionic acid treated grain for heavy animals).

In France, the development of maize cultivation has certainly allowed an acceleration in the organisation of youiig bull pro­duction in such a way that maize and maize silage are synonymous with modern cattle feeding.

Over the last few years many studies have been carried out on maize utilisation (whole plant, ears, grains or associations of these different parts). We are going to present here the main conclusions of the results obtained in France by INRA, ITCF or ITEB , for diets of whole crop maize silage and ears or grains ensiled or dried. A more complete review of this subject with a full list of references is given by Malterre (1976).

SUPPLEMENTING MAIZE SILAGE WITH HAY AND PROTEIN

a) The quantity and quality of hay offered When animals are given maize silage and hay ad libitum the

average hay intake varies between 0.5 and 2.0 kg/animal/day according to the quality of the hay. With medium or poor hay quality the reduction of energy supplied by the basal ration is followed by a lower growth rate and a lower feed efficiency than with maize silage alone. However, the conclusions may be very different with high quality hay. Thus, in 5 experiments, INRA was able to show that the provision of 1 kg good lucerne hay or grass hay would improve the growth rate by 60 or 130 g per day. The increase was higher with lucerne hay than with grass hay, and it seemed to be due to a higher DM intake.

419

b) Nitrogen supplements Crude protein supply; The more recent experiments carried

out in France have clearly demonstrated that the optimum levels are 850 - 900 g crude protein per day for dairy breed bulls (French Friesians, Normandes, Montbeliards, weaned at 13 - 12 weeks of age) between the weights of 150 and 550 kg. For bulls of beef breeds (from suckling herds and weaned at 7 or 8 months of age: Charoláis, crossbred Charoláis, Limousins, Salers, etc.) levels required are 1100 - 1150 g crude protein per day.

Nature of the protein source: Diets based on maize silage fulfil ideal conditions for a good utilisation of non-protein nitrogen such as urea. Nevertheless, according to some American experiments carried out on steers and some experiments in France with young bulls, the use of urea as the only nitrogen supplement for silage maize is followed by a big decrease in animal perform­ance (about 9 - 10% for both growth and feed efficiency). However, the rations studied had a crude protein content ranging from 13 - 14% DM for animals whose live weight was greater than 275 kg; this fact led us, in certain cases, to go beyond the limits of classically-recommended urea level. No urea toxicity, however, was reported.

It seems, therefore, wiser (except when protein cake has a very high cost) to add from 400 - 500 g cake or 1 kg high quality dehydrated lucerne to the maize silage + urea for animals with a high protein deposition, as in the case of our French breeds. In these conditions the reduction of the animals' performance seems limited to 3 - 4%.

UTILISATION OF MAIZE SILAGE GIVEN WITH OTHER FORMS OF MAIZE

a) Level of concentrate in the ration When the quality of maize silage is good, it seems that a

concentrate supplement (about 2 kg per day) allows good utilis­ation of this silage. Now, it happens that the harvest and storage of the silage become, in certain conditions, great problems for the farmer who wants to fatten a great number of animals with whole crop silage. It then can become valuable to associate ensiled maize with a high quantity of grain-maize or ears, or.even to use almost exclusively grain-maize or ears. According to the results of American experiments, when large

420 amounts of concentrate are given, generally associating maize silage with maize grain or ears, the rate of substitution of silage by concentrate is very high: 87% on average. According to the results of French experiments, this ratio seems to depend on the processing (either dried or moist) of maize ears and of grain which supplements the silage. This ratio depends also on the breed of animal (dairy or beef).

In this way we were able to re-calculate the substitution rate between maize silage and ground dried cereal in the case of a supplement of ground dry ears or grain-maize, when the amount of concentrate associated with silage was greater than 1.2 kg DM/day. This substitution rate was between 66 and 83% for dairy breeds (the highest rates of substitution were obtained from maize richest in DM) and between 83 and 87% for cattle of beef breeds. What followed was an improvement in the live weight gain by 42 g - 70 g per kg DM of cereal given beyond 1.2 kg/day, whatever the animal. Consequently, for dairy breeds the feed efficiency was not improved, on the average, except when the DM content of the silage was low. For beef breeds, the feed efficiency was improved: -0.10 to -0.30 kg DM intake per kg of gain when 1 kg of cereal was given as a supplement.

On the other hand, when maize silage was supplemented with moist grain-maize (stored as silaqe after grinding or after propionic treatment and rolling) or with ground maize-ear silage, the substitution range for whole plant silage by moist grain was higher than that between whole plant silage and dried grain: from 87 - 100% for dairy breeds and 100 - 143% for beef breeds.

So the distribution of moist cereals, compared to the distribution of dried cereals was followed by a lower increase, even by no increase at all, in the level of intake of the animals of dairy breeds and by a decrease in the level of intake of those of beef breeds. Per kg DM of cereal given as a supple­ment to the dairy breeds the growth rate and feed efficiency were, nonetheless, improved (respectively 40 to 56 g per day and -0.15 to -0.25 kg DM intake/kg of gain). For the beef breeds, per kg DM of cereal given as a supplement, the improvement in growth rate ranged from 15 to 110 g per day (50 g per day as a mean) according to the experiment and the decrease in feed conversion ranged from 0.10 to 0.60 kg DM intake/kg of gain.

421 In conclusion, for late maturing breeds, all the results

seem to be in favour of a supplementation of whole-crop silage with moist maize grain or ears, since the growth rate was as high as with dried maize and the level of intake was lower. For early maturing breeds (mostly dairy breeds) energy supple­mentation of maize silage is less efficient and is relatively more advantageous with low dry matter silages.

b) Influence of the method of processing maize grain or ears when associated with whole-crop silage

The comparison between different forms of maize grain or ears when given ad libitum and associated with whole plant silage has been the purpose of very little work. In 4 experiments carried out by ITCF and by INRA-CARA (Figure 1), we did not find any difference in feed efficiency between ground dried grain and moist grain (either ensiled or crushed and stored with propionic acid) when grain-maize amounted to 35 or 40% of DM intake. The utilisation of moist maize grain seemed the same whether the grain had been stored with propionic acid and crushed, or ensiled. On the other hand, the dried or moist grain maize had a much better utilisation when crushed before being given to the animals (9 to 11% improvement in feed efficiency). After grinding, however, Tonroy et al. (1974) concluded from 5 experiments that, when given as a supplement to a ration of 8 kg maize silage (fresh material) the moist maize grain (ensiled or stored with propionic acid) was consumed in smaller quantities than the dried grain (the difference being 4 to 15% of total DM intake). Moist grain was then utilised better by the animals. Moreover, there' was no notice­able difference between whole grain and crushed grain.

These results appear sometimes contradictory, but as yet we do not have sufficient data. Moreover the most suitable form of presentation for maize grain seems to depend on the proportion of whole plant silage in the ration. Thus, dry maize whole-grain might be utilised better when the intake of maize silage does not exceed 0.5 kg DM per 100 kg live weight, but ground dried grain might be more valuable in the case of a higher level of maize silage intake.

Klosterman et al. (1962) and ITCF showed that, as a supple­ment to maize silage, ground dried ears were consumed in larger

422

Figure 1

FORM OF MAIZE GRAIN IN COMPLEMENT OF WHOLE PLANT SILAGE Ο Δ Ο

Concernent : %£* &

. Grein artificial­ly dried

­ Ensued

form form 1300

-ΟΏ I200

. Prop. ac. treated _ ­Ear dried in cribs .Ensiled

MOO

IOOO

g/d AVERAGE DAILY GAIN

Λ y *"

òr' SS

<x kg DM/d. maize grain

kg kg

2.1­

2,0­

l,9

l,8

1,7

DRY MATTER INTAKE/ 100 KG BODY WEIGHT

D ­ ­ y *

12

π­

ιο

­ ρ ­0

τ ­2

o 1 2 3 Z7/?K MATTER INTAKE/KG CARCASSA GAIN

s

o Δ ­ * o f i

­τ­Ο

I * ! »ι«

1 2 3

/?e¿ INRAandITCF

423

Figure 2

MAIZE STORED IN MOIST FORM

1400 Comparison between :

­WHOLE PLANT SILAGE D (with or without cereal supplement) 1300

­ENSILED EARS

­ ENSILED GRAINS 0 1200­

­ GRAINS TREATED WITH PROPIONIC ACID e

Dairy breeds bulls

Beef breeds bulls

1100­

1000

. s AVERAGE DAILY GAIN (g) ^

'" / / J^ / ' /

/ ' /

feed concentration

CK

"Ho* "io" 70 — [ —

SO

DRY MATTER INTAKE/100 kg (kg) J D.M. BODY WEIGHT

\

es·—.­c. ­^~^3

2,2

2,0

i.sH

1,6

CCï

* Ό

9­

8­

feed concentration Ίο 6"0 Ϊ'Ο W

DRY MATTER INTAKE/kg CARCASS GAIN

D ­ — ^ " V . · ^ 'X­D~iy&­­:3

* ­ &

·>. V) feed concentration "NQ

■©

6Ό 70 6Ό

424 amounts than ensiled ears. However, owing to the slightly higher growth rate, the feed efficiency was very similar with the two forms.

UTILISATION OF GRAIN MAIZE OR MAIZE EARS GIVEN ALONE AND PRESENTED IN DIFFERENT FORMS

a) Utilisation of different forms of maize stored in moist condition: whole-crop silage, ensiled ears, ensiled grain or grain treated v/ith propionic acid

We have already considered successively the utilisation of the whole crop when given alone or associated with grain or ears and the utilisation of diets based on grain or ears. Many experiments have been done to compare the feeding .value of maize silage to that of ears or grain for growing or fattening steers. Here we present the first results obtained in France by INRA and ITCF (Figure 2).

In 8 feeding trials we compared the utilisation of ensiled maize ears to that of the whole ensiled plant. The growth rate of animals was higher (by 3 to 37%) with the diets of ears than with the whole crop diets. The voluntary food intakes were similar (-2% on average for ears) and ranged about a mean of 1.95 kg DM per 100 kg live weight for the whole-crop silage. Feed efficiency was better (by O to 24%; 16% on the average) for diets of ears than for whole-crop silage.

However, one must observe that with maize silage there are great variations in animal performances probably because of high variability in the whole-crop silage quality and these variations are greater than with moist ears or grain. One could conclude that the ears are clearly better than the whole plant silage.

The comparison of whole-crop silage with moist grain maize, either ensiled or treated with propionic acid, was studied in 6 feeding trials. As with the ears, maize grain had a better feeding value than the whole-crop silage: the growth rate of animals fed maize grain was higher by 8 to 9% (+ 160 g per day on the average) while DM intake was lower by 6.5%. Thus feed efficiency was greater by 14 to 22% (18.5% on the average) with maize grain, a difference slightly higher than that observed v/ith the ears.

425

Figure 3

DRY MATTER INTAKE/kg CARCASS GAIN

13

12

II-

10-

9

8·

7

O type laitier Δ type broutard

é^^JL

-τ 1 1 Whole Crushed Pelleted

DRY GRAIN

Ensiled Rolled Whole

MOIST GRAIN

426 b) Utilisation of maize grain or ears: effect of storage

and processing According to 13 feeding trials carried out in France by

ITCF and INRA (Figure 3), the method of storage or presentation of maize grain when the grain was given ad libitum, did not seem to have an effect on the growth rate of cattle of dairy breeds, which had always been very high (from 1200 to 1350 g per day according to the experiments). DM intake had always been greater with dried maize grain than with moist maize grain. Likewise it was greater with whole grain than with ground grain (especially in the case of dry grain). Thus, feed efficiency was better with the moist grain than with the dried grain.

On animals of beef breeds the differences between moist forms and dried forms seen greater than was the case for dairy breeds.

Here we have tried to compare the feeding value of different forms of dried and moist maize grain. We have not discussed the effect of technological treatments because they are very numerous and most of the time they do not induce a sufficient improvement in feeding value to compensate for the cost of treatment under French economic conditions.

CONCLUSION

Maize in different forms has great advantages and various ways of use. Using the whole plant or part of it, alone or in association, it is possible to make up diets varying in energy concentration according to the growth rate and the carcass weight to be achieved, to the economic conditions, farming conditions, and according to physiological stage, breed and genetic type of animals.

REFERENCES

Malterre, C. 1976. Different ways of utilising the maize crop for beef production. In: J.C. Tayler and J.M. Wilkinson (Editors) Improving the Nutritional Efficiency of Beef Production, Commission of the European Communities, Luxemburg.

427

Klosterraan, E.W., Johnson, R.R., Moxon, A.L. and Althouse, P. 1962. Feeding value of limestone-water treated ear corn silage with and without limestone treated whole plant corn silage. Ohio Agricultural Experimental Station Series No.128.

Tonroy, B.R., Perry, T.W. and Beeson, W.M. 1974. Dry, ensiled high-moisture ensiled reconstituted high-moisture and volatile acid treated high-moisture corn for growing-finishing beef cattle. Journal of Animal Science, 39 (5): 931-936.

Animal Feed Science ami Technology. 1 (1976) 429-440 4 2 9 tilsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands

NUTRITIVE VALUE OF DEHYDRATED WHOLE-CROP MAIZE

Y. GEAY and C. MALTERRE Institut National de la Recherche Agronomique, Centre de Recherches Zootechniques et Vétérinaires, Theix, 63110 Beaumont, France

ABSTRACT

Dehydrated and processed maize is less digestible, but is ingested in greater quantities, than the standing or ensiled whole crop. Given ad libitum, the size of the differences de­pends on the processing method. The live-weight gain of animals which receive this feed is little different from that of animals receiving silage. As a result, the feed efficiency is lower. Its energy value for fattening is, then, between 0.6 and 0.7 FU/kg of dry matter (DM) inclusive. On the other hand, when given in limited quantities its energy value seems to be superior.

INTRODUCTION

For the past 10 years in France, lucerne and grass dehydration factories have been interested in whole-crop maize in order to extend their activity for as long as possible at the end of the season, and thus to reduce the amortisation expenses of their installations. The use of dehydrated maize for the production of beef was the subject of a number of different studies in our country, at the Institut National de la Recherche Agronomique (INRA) and at the Institut Technique des Céréales et des Fourrages (ITCF), until the energy crisis stopped all research activity in this area. Nonetheless, from all of the studies carried out in France as well as abroad, it seems that the food value of whole-crop dehydrated maize can be different from that of silage maize, and that it varies according to a number of factors that we are going to consider.

DIGESTIBILITY

Dehydrated maize can be processed into different forms that facilitate its storage and distribution:'wafers, cobs or pellets

430

that differ in particle size. The digestibility of the organic matter of dried maize pellets or cobs distributed ad libitum to sheep as the sole feed is much lower than that of the standing or ensiled plant, (Demarquilly and Andrieu, 1973). It has only been, on the average, 59.6% for 9 samples studied by these auth­ors, and varied from 64.6 to 53.4% according to the fineness of grinding and the level of intake by the sheep. This poor digest­ibility essentially results from the reduction of time spent in the rumen and from the lowered cellulolytic activity of micro­organisms , (Jarrige et al., 1973). This reduction affects the digestibility of cell wall constituents, much more notably the crude cellulose.

The reduction of digestibility brought about by comminution is much less when the maize is distributed in limited quantities due to a reduced rate of passage through the digestive tract (Demarquilly and Andrieu, 1973). In this way the digestibility of organic matter and crude cellulose, which were 60.0% and 25.8% respectively for 4 samples given ad libitum by the preceding authors, went up to 66.7% and 44% respectively for these same samples distributed in limited quantities. These results are close to those obtained by Cottyn et al. (1973) for 9 samples of dehydrated pelleted maize, given in limited quantities to sheep. Still the lowered digestibility of roughages due to grinding is more or less compensated by an improvement in the utilisation of metabolisable energy for growth and fattening. (Blaxter and Graham, 1956; Wainman et al., 1972).

Crude protein digestibility is more influenced by the level of intake. On the other hand, it is notably reduced by the effect of dehydration, especially when carried out under high temper­ature (Demarquilly and Andrieu, 1973; Karn et al., 1974). None­theless under the effect of heating, protein solubility in rumen liquor is lower, and as a result, the proportion of non-degraded feed proteins in the rumen and digested in the intestine increases.

QUANTITY INGESTED AND THE ASSOCIATED ANIMAL PERFORMANCE

From all the results obtained in France as well as abroad, particularly in Belgium, dehydrated maize turns out to be very well-ingested by animals (1.7 to 2.15 kg DM per 100 kg live weight)

TABLE 1 INFLUENCE OF NATURE OF THE PROTEIN SOURCE

EXPERIMENTS

Breeds Dry Matter (DM) (%) of the

standing plant Processing form

Diet composition (%) :

. Whole-crop maize

. Dehydrated lucerne

. Cereal

. Cake

. Urea

. Minerals

. Straw

. Hay

Number of animals Length of period (d) Daily gain (g/d) DM intake (kg/d) DM intake/kg of gain (kg) Carcass weight (CW) (kg) Killing out percentage Kidney fat (% of CW)

ITCF_J

Montbé

1976)

liard

44.5 Pellets

68.2 -

11.9 10.3 -1.6 8.0 -

12 304 1209 8.43 6.97 296 54.5 4.1

68.3 -

18.3 2.5 1.1 1.7 8.1 -

11 315

1186 8.45 7.12 302 55.0 3.9

ITCF-EDE (1970)

Friesian

Pellets

83.2 --7.3 0.9 --8.6

12 150

1200 9.85 7.50 292 53.7 -

89.8 ---1.8 --8.4

12 150 1246 10.11 7.43 298 54.3 -

ITCF (1974)

Normande

30.5 Pellets

61.9 18.1 -

11.6 -1.1 7.3 -

11 320 1206 8.18 6.78 287 54.8 4.2

74.8 --

16.3 -1.8 7.1 -

11 316 1288 8.47 6.57 300 55.1 5.1

TABLE 2 INFLUENCE OF LEVEL OF INTAKE ON DAILY GAIN AND EFFICIENCY

EXPERIMENTS

Breeds Dry matter (DM) (%) of the standing plant Processing form

Whole plant of maize

Diet composition (%) : . Whole-crop maize . Cereal . Cake . Minerals . Straw

Number of animals Number of days Daily gain (g/d) DM intake (kg/d) DM intake/kg of gain (kg) Carcass weight (CW) (kg) Killing out percentage Fat in the carcass Kidney fat (% of CW)

ITCF (1976)

Montbeliard

44.5 Pellets

Ad.lib

68.2 11.9 10.3 1.6 8.0

12 304

1209 7.76 6.41 296 54.5

4.1

-10%

65.6 8.4

12.9 1.6

11.5

12 327

1163 7.26 6.24 299 53.8

3.2

-18%

63.0 4.4

16.0 1.7

14.9

12 322

1195 6.82 5.71 303 54.2

3.1

Malterre et al. (1971)

Danish Friesian

47 Cobs

Ad.lib

88.7 3.7 6.8 0.8

15 117

1250 11.91 9.60

295 51.5 18.5

-10%

87.4 4.2 7.5 0.9

15 117

1126 10.70 9.61

295 52.6 17:2

Malterre et al. (1971)

Montbéliard

41 Pellets

Silage

68.8 10.4 10.4 1.0 9.4

12 199

1246 8.12 6.03 306 55.4 19.2

Pellets limited

65.4 11.5 11.5 1.2

13.7

12 200

1241 8.56 5.98 308 55.1 15.5

433

and allows high growth rates (1000 to 1400 g/day). Nonetheless, the results varied with a certain number of factors such as the proportion of grain in the whole plant, the nature of the pro­tein source used, and the processing method. The proportion of grain in the whole plant.

This can be modified by the date of harvest, the date of sowing and the cutting height. An increase in the proportion of grain, due to a later harvest or an earlier sowing or even a higher cutting level, led to an improvement of feed efficiency (ITCF, 1971, 1972) (Fig.l). This was shown by either an increase in live-weight gain with no modification in ingested quantities (ITCF, 1971; Cordiez et al.,1975) or by a slight increase in live-weight gain, accompanied by a reduction in food "intake (ITCF, 1972). In fact, variations in grain content are accompanied by inverse variations in cellulose content (ITCF,1971, 1972). This goes along with the work of Gottyn et al. (1972) who showed that the net energy value of dehydrated maize varies as a function of cellulose content. Influence of the nature of the protein-source.

Whole-crop dehydrated or ensiled maize is low in nitrogen content, so it is necessary to supplement it in order to satisfy protein needs of young bulls during growth or fattening. This has been proved in the course of many studies using silage maize (Malterre, 1976) and verified with dried maize (Mattos, 1973). In France, ITCF carried out an experiment with young Charoláis bulls, and showed that a content of 13.5% crude protein in the DM was enough for these animals when their live weight was be­tween 300 and 590 kg inclusive.

Diets based on dehydrated maize fulfil ideal conditions for a good utilisation of non-protein nitrogen such as urea. In fact, dehydration produces a significant drop in soluble nitrogen con­tent in whole-crop maize (Zelter et al., 1971). Moreover the carbo­hydrate fraction that tends to provide rumen microorganisms with more readily available energy is considerably higher than in silage (Zelter et al., 1971) and thus allows a good utilisation of urea. As a result, contrary to what was observed with maize silage (Table 1), using urea as a supplement rather than protein cake does not result in a drop in live-weight gain or in feed efficiency (ITCF, 1970, 1974; Sibalic et al., 1974).

434

Fig. 1 Influence of the proportion of grain in the whole plant

1150

1100

1050

ïood

Daily gain (g/d)

of grain in the whole plant 10 20 30 40 50

2,7

2,6

2,5

2,4

η D.M. intake/100 kg body weight (kg)

% of grain in the whole plant

1

7,5­

7,0

6,5

lD.M . in take/kg.o f gain (kg)

% of grain in the^wfaple plant 1 1 1 2 , > » *■

435

Fig. 2 Influence of processing method

"D.H. intake (kg/d) 12 11 IO·· y,. 8 7

Si = Silage W = Wafers C = Cobs Ρ = Pellets

Si

1500 140Q 130C' 120C, 110Ü·

1000

10. ^D.H. intake/kg of gain (kg)

9.

a.

Si W C Ρ Same plant used in the experiment Different plant used in the experiment

436

Dehydrated pelleted lucerne given with protein cake can be used as a protein supplement for diets of dehydrated maize and to reduce the amount of cake provided (ITCF, 1974). Yet, intro­ducing dehydrated lucerne (18 to 19% crude protein) in the pro­portion of 60% of protein supplement produces a fall in live-weight gain and in feed efficiency, probably due to a reduction in the energy concentration of the feed. Influence of processing method.

In most of the experiments carried out, the utilisation of different forms of dehydrated maize was compared to that of en­siled maize, both being given ad libitum. From these comparisons, the following conclusions can be drawn.

(a) Dehydrated maize was always consumed in greater quantities than ensiled maize (Fig. 2 ) . The divergence was increasingly important as particle size decreased. Animals receiving wafers, cobs or pellets of maize actually ingested 107.5,115 and 121% respectively, of the quantity of DM ingested as silage.

(b) Dehydrated maize produced gains in live weight that were either slightly higher (107 and 110% respectively with cobs and maize pellets) or slightly lower (90.5% with maize wafers) than with ensiled maize.

(c) Feed efficiency was poorer with dehydrated than with en­siled maize. The DM intake per kg of gain accounted for 118, 108, 110% of the intake of silage, in wafers, cobs and pellets respect­ively. Moreover, the carcasses of animals receiving dehydrated maize were generally less fat than with silage.

The lower feed efficiency with dehydrated than ensiled maize is essentially due to a greater voluntary intake that led to a poorer digestibility. This assumption was confirmed in three experiments (ITCF, 1976; Malterre et al., 1971) in which DM in­take of dehydrated maize was restricted to 82% of ad libitum. In this case the daily gain of animals was similar, but the carcasses of animals receiving dehydrated maize were less fat (Table 2 ) .

Among the different processing forms, wafers seem to be less profitable because of the significant drop in live-weight gain. On the other hand the differences between cobs and pellets are slight, which was confirmed by the results of experiments where these two forms were compared directly. However, pelleted rations always required a minimum supply of long fibre, generally provided

437

Fig· 3 Influence of the respective proportions of pelleted dehydrated maize and barley grain

ι r Daily gain (g/d)

1300­

1200f

1100

^­A—

o o (ITCF­INA, 1968) « « (ITCF­INA, 1970) Δ & (ITCF, 1974)

■ o ­

% of grain in_ the dist

i

2,5

2,0

10 20 30 40 50 60 70 'D.M. intake/100 kg of live weight (kg)

~* — · ~ Γ — ~~ ■— Δ - Γ " ι ii »

Δ % of grain in the diet

8!

7

6­

<;.

10 20 30 40 50 60 70 D.M. intake/kg of gain (kg)

° a

^ ^ ^ = . ­ Λ

% of grain in the diet to 10 20 30 40 50 60 70

438

by sträv; (about 10% of the total ration) to ensure maintenance of rumination and to limit parakeratosis, rumenitis and bloat.

NUTRITIVE VALUE

From all the results presented above it appears that, when dehydrated maize accounts for more than 70 to 80% of the DM in the diet, its energy value is from 5 to 20% less than that of maize silage depending on whether dehydrated maize is given in the same quantities as silage maize or ad libitum. The value would thus be between 0.6 and 0.7 FU/kg of DM inclusive if the mean value for silage is 0.75 FU. This lower energy value, when dehydrated maize constitutes practically the total diet, appears to be confirmed by values obtained in experiments carried out on dairy cows (Demarquilly and Andrieu, 1973).

On the other hand, when dehydrated whole-crop maize accounts for less than 50% of the fattening diet and is given as a sub­stitute for grain (barley, Fig. 3 or maize) its energy value seems to be raised. It accounts for 81 to 90% of the value of barley (that is 0.8 to 0.9 FU/kg of fresh matter) in those experiments carried out by ITCF (ITCF, 1974; ITCF - EDE, 1970; ITCF - INA, 1968) and 78% of the value of maize grain (0.90 FU/kg of fresh matter) in an experiment done in Belgium (Boucqué et al., 1971). Still, the substitution value of dehydrated whole-crop maize would be expected to vary according to fibre content (from 0.82 to 1.02 FU/kg of fresh matter) as indicated in results obtained from 9 different samples. (Cottyn et al., 1973).

In conclusion, from the technical point of view, dehydrated maize could be very widely used for beef production. Indeed, when given ad libitum to animals during growth or fattening, it allows them to make high live-weight gains (1000 to 1300 g/day) with diets containing 80 to 90% of this product; moreover it offers the same advantages as other dehydrated roughages: harvesting facilities, handling, storage and distribution. In contrast with maize silage it can be sold easily and at any time.

What is more, as long as it is possible to limit animals, dehydrated maize has a feed value that is hardly different from that of maize silage, while it retains the above-mentioned advantages of dehydrated roughages. Finally, when given in place

439

of concentrated feed, its substitution value seems higher and superior to that of silage. Unfortunately its very high cost limits this use and the energy crisis removes any hope of improvement of this aspect.

REFERENCES

Blaxter, K.L. and Graham, N.M.C. 1956. J. Agrie. Sci., 47, 207­217. Boucqué, Ch. v., Cottyn, B.G. and Buysse, F.Χ. 1971. Revue de l'Agric.

Bruxelles, 10, 1295­1314 Boucqué, Ch. V., Cottyn, B.G. and Buysse, F.X. 1973. Proc. 1st Intern. Green

Crop Drying Congress, Oxford, April 1973. 217­227. Coehlo da Silva, J.F., Seeley, R.C., Prescott, J.Η.D., and Armstrong, D.G.

1972. Br. J. Nutr. 28, 357­371. Cordiez, E., Bienfait, J.M., Lambot, O­, van Eenaeme, C. and Pondant, Α. 1975.

Revue de l'Agric. Bruxelles. 2_, 315­329. Cottyn, B.G., Boucqué, Ch.V. and Buysse, F.X. 1972. Revue de l'Agric.

Bruxelles, 9, 1251­1255. Cottyn, B.G­, Joucqué, Ch.V. and Buysse, F.X. 1973. 5th Gen. Meeting of

European Grassi. Federation. Uppsala, June 1973. Demarquilly, C. and Andrieu, J. 1973. 24th Meeting of EFZ Vienne. 24/25'Sept. Jarrige, R., Demarquilly, C., Journet, M. and Beranger, C. 1973. Proc. 1st

Intern. Green Crop Drying Congr. Oxford, April 1973. 99­118. Karn, J.Fl, Rumery, M.G.A., Clanton, D.C. and Jones, L.F. 1974. J. Anim. Sci.

38, 850­853. Langlade, S and Malterre, C. 1974. Unpublished data. Malterre, C , Geay, Y., Bertin, G., Huguet, L. and Pelot, J. 1971. INRA Bull.

Tech. CRZV, Theix, 6 : 45. Malterre, C. 1976. Different ways of utilising the maize crop. "Improving

the nutritional efficiency of beef production". (Editors J.C. Tayler and J.M. Wilkinson) Commission of the European Communities, Luxembourg.

Mattos, J.C.A.D.E. 1973. Boletin de Industria Animal. 30 : 17. Sibalic, I..Kosanovic, M., Kunc, V. and Krajinovic, M. 1974. Zbornik Radova.

Institut Za Stocarstu Novi Sad. 7/8 : 75. Wainman, F.W., Blaxter, K.L. and Smith, J.J. 1972. J. Agrie. Sci. 78, 441­447. Zelter, S.Z., Charlet­Lery, G. and Tisserand, S.L. 1971. Ann. Zoötech. 20, 135. ITCF. Boigneville, 1971. Compte rendu d'expérience No. 11. ITCF. " 1972 " " No. 13. ITCF. " 1974 " " No. 33.

440

ITCF. Boigneville, 1974. Compte rendu d'expérience No. 50. ITCF. " 1976 " " No. 301. ITCF. " 1976 " " No. 404. ITCF. - EDE du Finistère, 1970 Compte rendu d'expérience Nos. 3 and 4. ITCF. ITCF. ITCF. ITCF.

1970 1970 1971 1973

ITCF. - INA. Vaux sur Aure, 1968 ITCF. " " 1970

No. 5. No. 6. No. 8. No. 12. No. 0. No. 3.

Animei Feed .Science ûnd Technology. 1 (1976) 441-454 4 4 1

I Iwvict Scientific Publishing Company. Amsterdam - Printed in The Netherlands

VOLUNTARY INTAKE AND EFFICIENCY OF UTILISATION OF WHOLE-CROP MAIZE SILAGE

J.M. WILKINSON The Grassland Research Institute, Hurley, Maidenhead, Berkshire, U.K.

ABSTRACT

The process of ensiling whole-crop maize is associated with major changes in composition which appear to be detrimental to nutritive value. Of particular significance is the production of organic acids and the degradation of plant protein to non­protein nitrogen (NPN). Intake may be increased by restricting fermentation, and since less fermentation occurs in drier crops than in wet, immature crops, the ensiling of crops at dry matter contents of 30-35% is recommended. There is also an improvement in net energy as the crop matures, which is related to an increase in starch content and a decrease in cell wall content. The extent to which supplementary NPN can be exploited in diets based on maize silage is limited by low levels of energy intake, and a relatively high content of NPN in the silage as a result of the fermentation process. In the presence of supplementary energy, differences in utilisation between sources of supplementary nitrogen are minimal. Many experiments have confounded energy intake with source of supplementary N, and more research is needed to understand fully the factors affecting rumen microbial protein synthesis in productive cattle.

INTRODUCTION

Maize silage is an important feed for beef cattle in Europe, but the extent to which it is used could be substantially higher than the present level. A major attraction of the crop is that it can support a greater output of live weight gain per hectare than other feeds such as cereal grain or intensively managed grassland (Wilkinson, 1976). However, there are nutritional limitations to the use of diets containing maize silage. Some are associated with intrinsic characteristics of the plant (for

442 example, its low content of protein and minerals), others are brought about by the ensiling process. In this paper, the influence of ensiling whole-crop maize on its subsequent nutritive value is discussed, together with ways of rectifying its major nutritional disadvantage, that of its low content of crude protein.

THE ENSILING PROCESS AND ITS INFLUENCE ON THE NUTRITIVE VALUE OF WHOLE-CROP MAIZE

The conservation of whole-crop maize as silage is associated with two major compositional changes, namely, the conversion of water-soluble carbohydrates to short-chain organic acids and the degradation of plant protein to non-protein nitrogenous compounds (Johnson et al., 1967; Andrieu and Demarquilly, 1974b; Bergen et al., 1974). These two changes may have a marked influence on the nutritive value of ensiled maize, since there is evidence with grass silages that the level of free acidity (McLeod et al., 1970), the level of acetic acid (Jackson and Forbes, 1970; Demarquilly, 1973) and the content of ammonia-N (Wilkins et al., 1971; Demarquilly, 1973) can influence voluntary intake. Yet relatively little research has been conducted with maize on the influence of ensiling on its nutritive value. The data in Table 1 summarise the results of four experiments in which fresh (or frozen) whole-crop maize was given to ruminants ad libitum in comparison with the same crop in the ensiled form. Voluntary intake of maize silage is lower than that of the original crop, though the magni­tude of the depression is variable. Possibly, the extent to which intake is depressed is a reflection of the amount of fermentation in the silo, which is greatly influenced by dry matter content (see next section).

TABLE 1 EFFECT OF ENSILING WHOLE-CROP MAIZE ON NUTRITIVE VALUE

Reference Noller et al. (1963) Dinlus et al. (1968) Andrieu and Demarquilly (1974a) Wilkinson et al. (1976)

% reduction due to ensiling Voluntary intake Liveweight gain

29 34 12 5 6 34

443 Live weight gain by cattle appears to be markedly reduced

as a result of ensiling(Table 1). This reduction may reflect a decrease in efficiency of utilisation of N, since Wilkinson et al. (1976) found that a lower proportion of ingested Ν was excreted in urine and a higher proportion of digested Ν was retained from frozen than from ensiled whole­crop maize. But more research is required to determine the significance to the nitrogen metabolism of cattle of the changes in nitrogenous constituents of whole­crop maize.

THE INFLUENCE OF DRY MATTER CONTENT ON THE NUTRITIVE VALUE OF MAIZE SILAGE

There is evidence that consumption of maize silage by cattle increases with increasing dry matter content (Huber et al., 1965; Huber et al., 1968; Johnson and McClure, 1968; Chamberlain et al., 1971; Malterre, 1976). Malterre (1976) concluded from a survey of 19 experiments that intake increased by 0.2 kg dry matter (DM) per 100 kg live weight (LW) between 20% and 35% DM content. Above 35 ­ 40% DM, intake decreased slightly. He also noted that younger cattle showed a greater response in intake than older animals.

Several possible explanations can be suggested for the response in intake to increasing DM content. Firstly, it may occur because cell wall content declines with advancing crop maturity as the ear component increases (Wilkinson and Osbourn, 1975; Penning, Wilkinson and Osbourn, unpublished data). This decrease is greatest as the dry matter content of the crop changes from 20% to 30%. Since the intake of forages is closely related to cell wall content (Osbourn et al., 1974), it is possible that intake is elevated in response to the decrease in the content of cell walls in more mature maize silage.

Secondly, intake may be increased because the extent of fermentation is less with drier crops than with wetter ones. The changes in the content of organic acids, and in the pro­portion of water­soluble (non­protein) Ν in the total Ν of the crop as DM content increases are shown in Figure 1, which includes data from experiments in the USA and in Europe. Elevated levels of acidity in ensiled maize, brought about by

444

íííeci of dr« matter content on tk* tentent of oraanit, adii In tn&he øslate

14

total organic acids 7 PM 10

'O

ţj=l4)7­0­17x * * *

20 30 40 50 drij malier content (7,)

60

H2O Soluble Ν ftíolalN)

Effect «ƒ art mûtUr contint o« th.« contint ci water -4olubl« nltroţcn In mail« »ilej*

50

40

35

30

25

20

ι$ = 7Οβ­0Τ7χ ***

30 40 50 Dru, malter content ('/, )

Figure 1

60

445

addition of organic acids to the silage prior to feeding have been found to be reflected in reduced levels of intake (Emery et al., 1961; Dinius et al., 1968; Wilkinson et al., 1976). Partial neutralisation of maize silage with sodium bicarbonate (Thomas and Wilkinson, 1975) or ammonia (Thomas and Wilkinson, 1974; Cottrill et al., 1976) has given increases in intake by young cattle. Thus the response in intake to advancing maturity may reflect a reduction in acidity (Figure 1) as dry matter content increases.

Thirdly, reduced degradation of protein to non-protein nitrogen (NPN) compounds at higher DM contents (Figure 1) may be reflected in an increased supply of undegraded plant protein to the abomasum, and this may enhance the intake of silage (Egan and Moir, 1965). For example, Cottrill (Table 4) found that the intake of a diet of maize silage supplemented with insoluble protein (fishmeal) was 10% higher than when the silage was partially neutralised by an iso-nitrogenous quantity of ammonia.

Gross (1970)established close correlations between dry matter content and nutritive value in ensiled maize. He concluded that net energy value increased as dry matter content (and the pro­portion of ear in the crop) increased. This increase in energy value was attributed to the accumulation of starch in the ear and a decrease in cell wall content, as previously noted. In a recent experiment (Penning et al., 1976) we found that the live weight gain by young calves given a diet in which maize silage of 20, 29 or 38% DM comprised 70% of total DM intake, was respectively 703, 769 and 833 (Í 34) g/day for the low, medium and high DM silages. This significant increase in performance was not a reflection of DM intake, which showed only a slight response to the change in DM content. Further, the improvement in performance occurred despite a significant decrease in digestibility of the organic matter and of the cell walls of the diet as DM content increased. However, the proportion of the digested organic matter which was derived from digested cell walls decreased as DM content increased (averaging 52.1, 40.1 and 37.6% for low, medium and high DM silage, respectively). It is probable that this decrease was a contributing factor to an increase in net energy which was reflected in the improved animal performance from the high DM silage diet.

446 One problem in assessing the impact of dry matter content

on nutritive value is that the content of ear, and of' starch, in the crop is closely correlated with whole-crop DM content (Demarquilly, 1969; Wilkinson and Osbourn, 1975). As the plant matures, there is a decrease in the content of water-soluble carbohydrates and an increase in the content of starch in the DM (Demarquilly, 1969). Thus, apart from the change in DM content per se there is also a marked change in the composition of the DM. Attempts to identify the influence of varying the proportion of ear on nutritive value at similar whole-crop DM contents are unlikely to be very successful (see, for example, Andrieu and Demarquilly, 1974a) because of the simultaneous changes in composition and DM content which occur with advancing maturity. Yet there is clear need for research to establish the quantitative importance of the ear component in relation to the energy value of maize silage. Little calorimetrie work has been conducted on this subject, and the information is needed to guide plant breeders in their search for improved varieties of forage maize.

THE INFLUENCE OF SUPPLEMENTARY NITROGEN ON THE NUTRITIVE VALUE OF MAIZE SILAGE

There is evidence that addition of supplementary nitrogen is associated with increased intake of maize silage by cattle, though the extent to which the response occurs is likely to be influenced by the composition of the diet, the source of supplementary nitrogen and the age and weight of the animal. Thomas et al. (1975a) found that consumption of maize silage (10.6% crude protein) by calves of 240 kg average live weight was elevated by 11% following supplementation with urea, but older cattle (340 kg live weight) and younger cattle (140 kg live weight) gave little response in intake to additions of urea. In a subsequent experiment (Thomas and Wilkinson, 1975) we found that the response occurred in young calves only when the silage was partially neutralised with sodium bicarbonate. In the absence of quantitative data on ruminai microbial protein synthesis in cattle given diets containing maize silage and supplementary nitrogen, it is only possible to speculate as to

447 the reasons for the response or lack of response in intake to additional nitrogen. Andrieu and Demarquilly (1974b) noted that sheep gave a response in intake as the crude protein content of maize silage increased up to the level of 9-10% of the DM. Thereafter there was no response. This response in intake to level of protein was associated with a similar response in digestibility of organic matter. In our work with calves (Thomas et al., 1975a; Thomas and Wilkinson, 1975) we have not recorded large responses in digestibility of organic matter following supplementation of maize silage by urea. Possibly, rate of digestion is enhanced by addition of urea (rather than digestibility), allowing a greater level of consumption and an increase in the total supply of protein to the small intestine.

There is little doubt that the young ruminant responds in efficiency of feed utilisation to the supplementation of maize silage with nitrogen. For example, Thomas and Wilkinson (1975) found that addition of urea, (at 2% of the silage DM) to maize silage of 8.4% crude protein was reflected in a 70% increase in the proportion of ingested Ν retained. The calves were given silage as the sole feed at 2.3% of live weight. This observation suggests a response in microbial protein synthesis to the addition of urea. We found that the content of rumen ammonia nitrogen (NH3-N) in the calves given silage without urea was only 3 mg/ 100 ml, well below the level of 5 mg/100 ml which was suggested by Satter and Slyter (1974) as being necessary to maintain maximal microbial protein synthesis.

However, the high requirement for amino acid nitrogen to sustain rapid lean tissue growth in young calves may not be met even at maximum efficiency of microbial protein synthesis. This point is illustrated by experiments in which ammonia was added immediately prior to feeding to immature maize silage of low DM and high crude protein content. This was done to partially neutralise silage acidity and at the same time increase the content of nitrogen in the diet. When the silages were given ad libitum to young calves (100 kg live weight), intake increased by a maximum of 14.6% at the highest level of addition of ammonia (Table 2). The levels of rumen NH3-N rose from a relatively high basal level of 10.8 to 22.9 mg/100 ml with increasing level of addition of NH3. When the silage was subsequently given at a

448

TABLE 2 EFFECT OF ADDITION OF AMMONIA TO MAIZE SILAGE PRIOR TO FEEDING ON VOLUNTARY INTAKE OF DM, RUMEN ΝΗ-,-Ν AND BLOOD UREA-N

pH of silages Ν χ 6.25 (% of DM) Voluntary intake of DM(% of LW) Rumen NH^-N (mg/100 ml) Blood urea-N (mg/100 ml)

0 3.82 11.3

2.26

10.8

5.83

(1) *, **, *** significant effe respectively.

Level of to silage

0.32 3.95 13.3

2.29

12.4

9.27

ct of trea

NH3-N added (4 of DM)

0.53 4.27 14.6

2.43

18.6

12.5

tment at Ρ

0.80 4.60 16.3

2.59

22.9

14.9

<0.05,

SE

0.48**(1)

1.23***

0.64***

0.01 and 0.001

from Thomas and Wilkinson (1974)

TABLE 3 EFFECT OF ADDITION OF AMMONIA TO MAIZE SILAGE PRIOR TO FEEDING ON UTILISATION OF NITROGEN

Ν χ 6.25 in (% of DM) Intake of Ν Ν in faeces Ν in urine Ν retained Ν retained (% Ν intake) Rumen NF^-N, (mg/100 ml) Blood urea-N (mg/100 ml)

silage

(g/day) " " "

'

0

11.9 36.7 14.5 11.7 6.65

17.6

13.2

5.80

Level of NH3-to silage (%

0.64

13.8 40.8 14.6 20.4 2.57

6.4

23.5

11.2

-N added of DM)

1.20

17.1 52.5 14.7 29.9 4.60

8.6

37.5

15.5

SE

0.96*** 0.27 ns 1.15*** 1.055 ns

2.43*

1.29***

0.51***

Wilkinson (unpublished data)

449

restricted level of DM (1.9% of LW) there was no response in efficiency of utilisation of Ν to additional ammonia (Table 3). Since rumen NH3­N levels exceeded 10 mg/100 ml in both experiments, efficiency of microbial protein synthesis was probably maximal. This relatively high level of ruminai NH3­N in the calves given maize silage with no additional Ν probably reflected the relat­ively high level of water­soluble Ν (51% of total N) in the silage. In a subsequent production trial (Table 4) there was a large response in intake and performance to the feeding of fish­meal, compared to that from iso­nitrogenous levels of urea or ammonia, indicating a possible benefit to total protein supply of including a source of insoluble Ν in the diet.

TABLE 4 EFFECT OF ADDING UREA, AMMONIA OR FISHMEAL TO MAIZE SILAGE INTAKE AND LIVE WEIGHT GAIN BY YOUNG CALVES

(1) ON VOLUNTARY

Supplement

pH of silage Intake of DM (% of LW) Live weight gain(kg/day)

(1) . to give a conte

Urea

4.0

1.78

0.46

nt of Ν χ 6

Ammonia

5.0

2.39

0.39

.25 of 15% c

Fishmeal

4.0

2.63

0.97

f the DM

Fishmeal + NaHCOß

5.0

2.73

1.03

SE

.109

.066

Cottrill (unpublished data) In the presence of supplementary energy, on the other hand,

we have not detected significant differences between urea and fishmeal in their value as supplements of nitrogen for diets consisting predominantly of maize silage (Table 5). Since live weight gain was greater (by 20%) for the supplemented diets than for the control diet which contained the same level of concen­trate, and since intake of DM was similar between the control diet and the rest of the diets, the results suggest that in the presence of supplementary energy, urea is utilised in microbial protein synthesis to give a similar total supply of protein to the animal to that provided by fishmeal.

Thus the scope for efficient utilisation of non­protein

TABLE 5 EFFECT OF SOURCE, AND SITE OF ADDITION OF SUPPLEMENTARY NITROGEN ON VOLUNTARY INTAKE AND EFFICIENCY OF UTILISATION OF MAIZE SILAGE BY YOUNG CALVES

Site of addition:

Total Ν χ 6.25 (% of DM)

Dry matter intake (°¿ of LW) Live weight gain/ (kg/day) Live weight gain/ 100 kg DMI Live weight gain/ 100 g Ν intake

At ensiling Control Urea Fishmeal

12.8

2. 52

0.79

21.3

1.01

16.2

2.60

0.93

23.6

0.90

15.9

2.58

0.94

24.1

0.93

At feeding Urea Fishmeal

15.6

2.74

0.95

22.7

0.88

15.3

2.58

0.93

23.0

0.92

In concentrate Urea Fishmeal

15.3

2.63

0.96

23.8

0.97

14.9

2.62

0.96

23.3

0.97

(1) A 50% dried grass, 501 barley concentrate comprised 331 of the total daily DM intake of each treatment

Thomas et al. (1975b)

451 nitrogen appears to be severely restricted, by a deficiency in energy consumption, when maize silage is the sole source of energy in the diet. It may also be restricted by the presence of a large proportion of NPN in the silage, particularly when the silage is made from a relatively immature crop which has undergone extensive fermentation, as was the case in the experiments reported in Tables 2 and 3. In this situation, large responses in utilisation of maize silage by cattle may occur as a result of supplementing the silage with either energy or a source of insoluble protein such as fishmeal. However, further research is necessary to determine the relative values of different sources of supplementary nitrogen when given to cattle in combination with different quantities of supple­mentary energy.

CONCLUSIONS

Research is needed to establish more clearly the reasons for the depression in nutritive value which occurs when whole-crop maize is ensiled. Particular attention should be paid to the degradation of protein during ensilage and its impact on efficiency of utilisation of nitrogen by productive cattle.

There is need to define with greater precision the optimal nutritional regimes for the utilisation of NPN in diets contain­ing maize silage. This work should involve studies of protein and energy digestion, and should take account of the close inter­relationships between the two, since in many experiments differences in intake of energy have confounded comparisons between sources of supplementary nitrogen (see Thomas et al., 1975a).

Increased knowledge of the factors affecting the nutritive value of ensiled maize should facilitate more judicious use of supplements and enhance the efficiency of beef cattle production in Europe.

452

REFERENCES

Andrieu, J. and Demarquilly, C. 1974a. Valeur alimentaire du mais fourrage. II Influence du stade de végétation, de la variété, du peuplement, de l'enrichissement en épis et de l'addition d'uree sur la digestibilite et 1'ingestibilité de l'ensilage de mais. Annales de Zootechnie, 23, 1-25.

Andrieu, J. and Demarquilly, C. 1974b. Valeur alimentaire du mais fourrage. III Influence de la composition et des characteristiques fermentaires sur la digestibilite et 1'ingestibilité des ensilages de mais. Annales de Zootechnie, 23, 27-43.

Bergen, W.G., Cash, E.H. and Henderson, H.E., 1974. Changes in nitrogenous compounds of the whole corn plant during ensiling and subsequent effects on dry matter intake by sheep. Journal of Animal Science, 39, 629-637.

Chamberlain, H.C., Fribourg, H.A., Barth, K.M., Felts, J.H. and Anderson, J.M. 1971. Effect of maturity of corn silage at harvest on the performance of feeder heifers. Journal of Animal Science, 33, 161-66.

Cottrill, B.R., Osbourn, D.F., Wilkinson, J.M. and Richmond, P.J. 1976. The effect of dietary pH and nitrogen supplementation on the intake and utilisation of maize silage by young calves. Animal Production, 22, 154-55 (Abstract)

Demarquilly, C. 1969. Valeur alimentaire du mais fourrage. 1. Composition chemique et digestibilite du mais sur pied. Annales de Zootechnie, 18, 17-32.

Demarquilly, C. 1973. Composition chemique, characteristiques, fermentaires, digestibilite et quantité ingérée des ensilages de fourrages: modifications par rapport au fourrage vert initial. Annales de Zootechnie, 22, 1-35.

Dinius, D.A., Hill, D.L. and Noller, C.H. 1968. Influence of supplemental acetate feeding on voluntary intake of cattle fed green corn and corn silage. Journal of Dairy Science, 51, 1505-07.

Egan, A.R. and Moir, R.J. 1965. Nutritional status and intake regulation in sheep. 1. Effects of duodenally infused single doses of casein, urea and propionate upon voluntary intake of low protein roughage by sheep. Australian Journal of Agricultural Research, 16, 437-49.

Emery, R.S., Brown, L.D., Huffman, CF., Lewis, T.R., Everett, J.P. and Lassiter, C.A. 1961. Comparative feeding value of lactic acid and grain for dairy cattle. Journal of Animal Science, 20, 159-62.

453

Gross, F. 1970. Einfluss des erntezeitpunktes auf den futterwert von maisgarfutter. Das Wirtschaftseigene Futter, 16, 306-36.

Huber, J.T., Graf, G.C. and Engel, R.W. 1965. Effect of maturity on nutritive value of corn silage for lactating cows. Journal of Dairy Science, 48, 1121-23.

Huber, J.T., Thomas, J.W. and Emery, R.S. 1968. Response of cows fed urea-treated corn silage harvested at various stages of maturity. Journal of Dairy Science, 51, 1806-16.

Jackson, N. and Forbes, T.J. 1970. The voluntary intake by cattle of four silages differing in dry matter content. Animal Production, 12, 581-99.

Johnson, R.R., McClure, K.E., Klosterman, E.W. and Johnson, L.J. 1967. Corn plant maturity 3. Distribution of nitrogen in corn silage treated with limestone, urea and diammonium phosphate. Journal of Animal Science, 26, 394-99.

Johnson, R.R. and McClure, K.E. 1968. Corn plant maturity 4. Effects on digestibility of corn silage in sheep. Journal of Animal Science, 27, 535-40.

Malterre, C. 1976. Different ways of utilising the maize crop for beef production. In: J.C. Tayler and J.M. Wilkinson (Editors). Improving the Nutritional Efficiency of Beef Production. Commission of the European Communities, Luxemburg.

McLeod, D.S., Wilkins, R.J. and Raymond, W.F. 1970. The voluntary intake by sheep of silages differing in free-acid content. Journal of Agricultural Science, Cambridge, 75, 311-9.

Noller, C.H., Warner, J.E., Rumsey, T.S. and Hill, D.L. 1963. Comparative digestibilities and intakes of green corn and corn silage with advancing maturity. Journal of Animal Science, 22, 1135 (Abstract).

Osbourn, D.F., Terry, R.A., Outen, G.E. and Cammell, S.B. 1974. The significance of a determination of cell walls as the rational basis for the nutritive evaluation of forages. Proceedings of the XII International Grassland Congress, Moscow, Section 5, 514-9.

Penning, l.M., Wilkinson, J.M. and Osbourn, D.F. 1976. Effect of stage of maturity and fineness of chopping on the nutritive value of maize silage. Animal Production, 22, 153-54 (Abstract)

Satter, L.D. and Slyter, L.L. 1974. Effect of ammonia concentration on rumen microbial production in vitro. British Journal of Nutrition, 32, 199-208.

454

Thomas, C. and Wilkinson, J.M. 1974. The voluntary intake of maize silage treated with ammonia. Proceedings of the British Scoeity of Animal Production, 3, 102-3 (Abstract).

Thomas, C. and Wilkinson, J.M. 1975. The utilisation of maize silage for intensive beef production 3. Nitrogen and acidity as factors affecting the nutritive value of ensiled maize. Journal of Agricultural Science, Cambridge, 85, 255-61.

Thomas, C , Wilkinson, J.M. and Tayler, J.C. 1975a. The utilisation of maize silage for intensive beef production 1. The effect of level and source of supplementary nitrogen on the utilisation of maize silage by cattle of different ages. Journal of Agricultural Science, Cambridge, 84, 353-64.

Thomas, C. Wilson, R.F., Wilkins, R.J. and Wilkinson, J.M. 1975b. The utilisation of maize silage for intensive beef production 2. The effect of urea on silage fermentation and on the voluntary intake and performance of young cattle fed maize silage-based diets. Journal of Agricultural Science, Cambridge, 84, 365-72.

Wilkins, R.J., Hutchinson, K.J. , Wilson, R.F. and Harris, C E . 1971. The voluntary intake of silage by sheep 1. Inter-relationships between silage composition and intake. Journal of Agricultural Science, Cambridge, 77, 531-37.

Wilkinson, J.M. 1976, Forage crops versus grain crops In: J.C. Tayler and J.M. Wilkinson (Editors) Improving the Nutritional Efficiency of Beef Production. Commission of the European Communities, Luxemburg.

Wilkinson, J.M., Huber, J.T. and Henderson, H.E. 1976. Acidity and proteolysis as factors affecting the nutritive value of corn silage. Journal of Animal Science, 42, 208-18.

Wilkinson, J.M. and Osbourn, D.F. 1975. Objectives in breeding forage maize for improved nutritive value. Proceedings 8th Congress of Eucarpia, Maize and Sorghum Section, Versailles, France, September 1975

Animal Feed Science and Technology. 1 (1976) 455-464 4 5 5 (ilsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands

THE DIGESTION AND METABOLISM OF THE ENERGY AND PROTEIN OF MAIZE

D.E. BEEVER

The Grassland Research Institute, Hurley, Maidenhead, Berkshire, SL6 5LR, England

ABSTRACT

This paper has attempted to review the carbohydrate and pro­tein digestion of maize grain and maize silage fed to ruminants. Attention has been drawn to the ability of ground maize markedly to increase the supply of glucose to the tissues, as a result of an increase in the amount of starch which escapes ruminai de­gradation, whilst the possible inferiority of ground maize com­pared with flaked maize in relation to protein supply has been discussed. Theoretical calculations have indicated why maize silage is unable to supply adequate protein to meet the animal's requirements, and attempts to establish an optimal level of in­clusion of protected prctein have been made. Further attention has been drawn to some of the factors influencing microbial act­ivity within the rumen.

INTRODUCTION

The development of reliable techniques for the insertion of re-entrant cannulae into the alimentary tract of ruminants (Brown, Armstrong and MacRae, 1968) and an improved understanding and use of radioactive tracer techniques (Annison, 1964) has, over the last 10 years, led to a fuller elucidation of the mechanisms of rumen fermentation, and how the balance of the end products of digestion may be influenced by chemical or physical modifi­cation of the diet (Osbourn, Beever and Thomson, 1976) and fre­quency and level of feeding. It is not the intention of this paper to review the various reactions which occur in the rumen, and the subsequent digestive processes in the hindgut, but to consider some of the interesting features of maize grain digestion and, in the absence of any available data, attempt to construct a digestion pattern for maize silage.

45(>

MAIZE GRAIN

Whilst two forms of maize grain are generally available for feeding ruminants in the United Kingdom, the proportion consumed as flaked maize is considerably greater than the amount of ground maize used. Clearly starch comprises the major nutrient in all forms of maize grain, and MacRae and Armstrong (1969) observed with a hay:flaked maize diet (1:2 by weight), fed to mature sheep, an overall starch digestibility of 100%, with 90% of the (digest­ible) starch being lost within the reticulo-rumen. From the studies of Beever, Coehlo da Silva and Armstrong (1970), who fed a diet of 80% flaked maize, 20% dried grass, similar data were obtained, indicating 100% overall digestion, with 96% of this digestion occurring within the rumen. Thus it could be shown that for a total dry matter intake of 1 kg/day, of which flaked maize comprised 80%, the diet provided only 26 g of starch which was digested in the small intestine, but approximately 6.3 moles of rumen VFA, based on the stoichiometric data of Baldwin, Lucas and Cabrera (1970).

In contrast, when Beever et al". (1970) fed a similar diet but with the flaked maize replaced by ground maize, 139 g of digestible starch entered the small intestine, whilst VFA pro­duction from ruminai digestion of the cereal was reduced to a computed value of 5.0 moles/day. Whilst Beever et al. (1970) did not study the molar proportions of rumen VFA on the flaked maize and ground maize diets, there is evidence from other work, (Harrison, Beever, Thomson and Osbourn, 1975; Thomson and Beever, 1976, and D.E. Beever - unpublished observation) that the molar proportion of propionate is not influenced by the physical form of the grain. For twice-daily feeding situations, Harrison et al. (1975) and Thomson and Beever (1976) found a mean value of 30% propionate for flaked maize (60% of diet), whilst for ground maize which comprised 65% of the diet, D.E. Beever (unpublished observation), found a value of 29%. If VFA proportions can be extrapolated to VFA production rate (Armstrong and Prescott, 1970) then from the computed VFA yields, the yields of propionate can be derived. Assuming this is totally converted to glucose, then the total supply of glucose from propionate, and from glucose absorbed from the small intestine, was found to be 94 g/kg dry

457

matter consumed on the flaked maize diet of Beever et al. (1970) but 193 g/kg DM on the ground maize diet. The importance of this in terms of the animal's requirement is discussed by Armstrong and Prescott (1970) who calculated the minimal glucose require­ment of a 590 kg cow yielding 20 kg milk of 4% fat and 4.7% lactose to be 1494 g/day. With a ration formulated to ARC (1965) requirements, of 50% hay, 7% soya bean meal and the re­mainder as rolled barley or ground maize, they concluded that glucose from the small intestine would provide only 15% of the glucose requirement on the barley diet, but 78% on the ground maize diet. Clearly large benefits can be derived from the feed­ing of ground maize when glucose requirement is high, such as in pregnancy or lactation, with an associated sparing of amino acids from gluconeogenesis although definitive experimentation on this latter aspect is not available.

The mechanism of this response with ground maize has eluded full elucidation. The size of the particle presented to the rumen may facilitate greater passage, as has been demonstrated with finely ground forages (Osbourn et al., 1976), whilst the possibility of an elevated flow of microbial polysaccharide, in particular that of protozoal origin, cannot be ignored. However, it is pertinent to note that attempts to reproduce this response with barley or wheat have proved unsuccessful (Ørskov, Fraser and Kay, 1969), and from this we may conclude that the physical form of the grain is responsible. Kerr (1950) demonstrated a horny endosperm in maize, quite different from barley grain, and in this respect a slowing down in the rate of raw maize digestion within the rumen might be expected; an effect which is probably negated when maize is heat treated in the flaking process prior to feeding.

Consideration of the protein supply of flaked and ground maize, however, reveals quite a different situation. With the two diets fed by Beever et al. (1970) the crude protein content (Ν χ 6.25) was 11.0% forthe diet containing flaked maize and 11.7% for that containing ground maize. However, despite a slightly higher intake of Ν on the ground maize diet, the amounts flowing at the duodenum and digested in the small intestines were greater on the flaked maize diet (see Table 1). It would appear that such values are related to the extra energy, and, in particular, the extra carbohydrate energy, digested in the rumen on the flaked maize diet, and possibly a slight increase

458 in the amount of cereal protein escaping rumen degradation on the heat-treated diet. In consequence, total protein uptake was 12 o higher on the flaked maize diet. When expressed as g truly digestible protein absorbed from the small intestine/MJ energy absorbed from the total tract (Thomas and Clapperton, 1972), the value for flaked maize (7.0) was higher than the value derived for the ground maize (6.3).

TABLE 1 THE MEAN QUANTITIES OF NITROGEN CONSUMED AND ENTERING AND LEAVING THE SMALL INTESTINE OF SHEEP

Nitrogen g/d: In feed At proximal duodenum At terminal ileum

Flaked maize

17.6 24.8 7.9

Ground maize

18.8 22.4 7.4

(Sheep receiving 1 kg dry matter per day of a flaked maize: dried grass or ground maize: dried grass diet, in which the maize component comprised 80% of the dry matter)

When compared with the calculated truly digestible protein requirements given by Egan and Walker (1975), assuming a BV of 75%, the flaked maize supplied sufficient truly digestible pro­tein to meet maintenance requirements in cattle up to 400 kg liveweight or for 500 kg cows in the 5th month of lactation, whilst ground maize failed to meet the protein requirements of all classes of ruminant livestock reviewed by Egan and Walker (1975). In this situation, where flaked or, in particular, ground maize comprises a large part of the diet, recourse to supplement­ation of the diet with protected protein would be essential if requirements were to be met.

MAIZE SILAGE

The task of considering maize silage is made difficult by the absence of any published detailed digestion studies. Current experimentation at this Institute is measuring the quantity and composition of the end products of digestion of maize silage fed with varying amounts of urea or fishmeal, sufficient to pro-

459

vide 2.6% Ν in the dry matter. However, to date, no data are available. Clearly the composition of maize silage can vary according to the time of harvesting, the type of cutter used and the resulting ensiling process (Wilkinson, Penning and Osbourn, unpublished observation). For this paper I have considered mat­erial harvested at a dry matter content of 27 ­ 30%, with a pre­cision chop harvester. The resulting silage has been shown to have approximately 28% starch and 25% cellulose, with a total organic acid content of 5.6%. Nitrogen content was found to be 1.4%, of which 10% was ammonia­N and 50% water­insoluble N. In the absence of reliable data, it may be calculated that the supply of glucose to the small intestine on a diet of maize sil­age would be of the order of 50 g/kg dry matter consumed, assuming total digestion of starch within the alimentary tract and with 20% of this occurring post­ruminally. Clearly this value of 50 g exceeds the amount found on all­cereal diets other than ground maize, and may be important when the values of 20% or so for the molar proportion of propionic acid of calves fed maize silage, reported by Thomas and Wilkinson (1975) are considered in relation to the animals' overall glucose economy.

The most controversial issue about the nutritive value of maize silage is regarding the protein content. Several workers (Thomas, Wilkinson and Tayler, 1975; Cottrill, Osbourn, Wilkin­son and Richmond, 1976) have shown maize silage and urea to be an inadequate diet for calves less than 6 months of age, and have clearly defined the importance of including preformed protein in the diets fed to such animals. Clearly with its ,low Ν content and the large proportion which is non­protein in origin, maize silage is most inadequate for meeting the protein requirements of the animal. From the data of J.M. Wilkinson (unpublished observation) it may be concluded that as much as 35% of the Ν in the crop is of non­protein origin, with the true protein content of the crop being as low as 6%. With these assumptions, application of the data to the Metabolisable Protein model of Satter and Roff1er(1975), which is based on earlier work of Burroughs, Trenkle and Vetter (1974), achieved the data outlined in Figure 1. An estimate of absorbed (metabolisable) energy was derived from the data of Thomas and Clapperton (1972). The value of 5.6 g of digestible true protein/MJ ME was considerably less than the lowest value of

460

Fî$J Calculation oí the irtthţ diçee i íMr protein¡IK'S mtfobolhaMt CïlCrO^ 0$ matte Ç'ÛCLtt i^aíicr Sate r fi. RoØler 1975)

1 kiloçram maire silage drç matter

l­4gNH3N

9­5a protein Ν Y Ξ 59­4$ protein

4­6a,N

Iluminai NH3 Pool' 4·6α,Ν 5­7s Ν «ι

Escapes Ruminai degradation

, _ U PLASM ¡ ''

ZS ~~Ί UREA POOL j

(microbial M) ».microbial

~ ^ Ν PW frZa,) 3­1 $

• *ιί*. » y JAECES ^ microbial tme­N *

55· δ a, microbial true protein

1 25· 8a, protein

IO· 8a,

43­Oa, Digestible. 20·Ύα/

65·7α, D i b b l e True Protein ^ ^ ^ . ^

Calculated absorWd etiera^­II^MJ/ka, DM iru* ?roïcinl^­M£

461

6.7 given by Egan and Walker (1975) which they said was necessary to meet the protein requirements of 200 ­ 400 kg cattle at maint­enance. Inclusion of fishmeal sufficient to raise the crude pro­tein (Ν χ 6.25) content of the diet to 14% raised this value to 7.7, which was still insufficient to meet the protein require­ments for growing lambs, but adequate for up to almost 1 kg live­weight gain per day in growing cattle. Further inclusion of fishmeal to a crude protein content of 16%, gave a computed value of 9.2, which from Egan and Walker's data would meet most protein requirements for growth, and in most instances would supply an excess.

Recent work at this Institute has been considering a range of factors likely to influence microbial synthesis within the rumen. McMeniman, Ben Ghadalia and Armstrong (1975) from a re­view of the literature concluded that on cereal diets the yield of microbial Ν in relation to organic matter (OM) digested within the rumen was 2.2 g/100g OM whilst a value of 3.3 g/100g OM was derived for forage diets. The mechanism responsible for such changes is not clear, although the work of Harrison et al. (1975) indicated that the turnover rate of the rumen fluid (dilution rate, Warner and Stacy, 1968) may be important. In this context, diets containing large amounts of cereals have inherently low dilution rates, whilst forage­containing diets have much higher values. Recent work conducted in this laboratory has considered the effect on microbial protein synthesis of varying the ratio of readily available carbohydrate to structural carbohydrate digested in the rumen. The amounts of water­soluble carbohydrate and starch digested in the rumen were termed the o¿linked carbo­hydrate, whilst digested cellulose and hemicellulose were termed the /Q linked carbohydrate and diets were classified according to the oc : /β ratio. Preliminary data for a range of diets is shown in Table 2, indicating that as the o<. : & ratio increases so the efficiency of microbial synthesis declines. From the data of J.M. Wilkinson (personal communication) it can be con­cluded that the oc : £ ratio was of the order of 1:1, and from this we may conclude that microbial synthesis is highly efficient and may indicate why little response to additions of non­protein nitrogen is obtained.

462

TABLE 2 RELATIONSHIP BETWEEN THE RATIO OF READILY AVAILABLE CARBOHYDRATE ( O". ) TO STRUCTURAL CARBOHYDRATE US> ) DEGRADED IN THE RUMEN, AND MICROBIAL DRY MATTER SYNTHESISED PER MOLE ATP PRODUCED (Y (ATP))*

Diet (with % compo

Ground maize (65) Rolled barley (41) Ground maize (25) Rolled barley (19) Grass pellet (57)

sition)

Dried grass (35) Formalin silage (59) Grass pellet (75) Lucerne (81) Grass silage (43)

CX. :xS

3.3 2.4 1.8 0.7 0.6

Y (ATP)

10.0 13.7 13.3 17.3 16.8

Data: D.E. Beever (unpublished observation) * Hobson (1965)

CONCLUSIONS