P~.tNcrPLES AND. rN PHrLrPNNE CoNTEXf - NAST Philippines files/Publications...University of the Philippines Press, c2008. p.; ern. 1. Animal breeding-Philippines. 2. Breeding Philippines.

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P~N(!IPL£5 AND P~errC£ rN THE PHtLtPPtNE CoNTEXT

ORVILLE L. BONDOC

The University of the Philippines Press "' -Diliman, Quezon City

THE UNIVERSITY OF THE PHILIPPINES PRESS E. de los Santos St., UP Campus, Dilirnan, Quezon City 1101 Tel. No.: (02)925-3243, (02)926-6642/Telefax No.: (02)928-2558 e-mail: [email protected]

© 2008 by Orville L. Bondoc All rights reserved. No copies can be made in part or in whole without prior written permission from the author and the publisher.

The National Library of the Philippines CIP Data

Recommended entry:

Bondoc, Orville L.

Animal breeding: principles and practice in the Philippine context I Orville L. Bondoc.-Quezon City: The University of the Philippines Press, c2008.

p.; ern.

1. Animal breeding-Philippines. 2. Breeding­Philippines. 3. Animal genetics-Techniques. I. Title.

SF105 636.082 2009 P091000060 ISBN 978-971-542-589-6

Book Design by Zenaida N. Ebalan

Printed in the Philippines by EC-tec Commercial

Contents

Foreword .......... .. .. .... .... .. ............................... ................. .............. xxi

Acknowledgements ............ ..................................... .................. ... . xxiii

Chapter 1: Introduction

Summary ............. .............. .. ..................................................... .. 1

A. Definition of Animal Breeding ............................ .. .......... .. !

B. Goals of Animal Breeding ................................................. 4

C. Short History of Animal Breeding ............................ ...... .. 5

D. Overview of Animal Breeding Industries .. ...... ........... .. .... 6

l. Value of improvement ................................................ 9

2. Role of the government .. ......................................... . 10

E. Research in Animal Breeding .......................................... 10

Chapter 2: Genetic Basis of Animal Differences

Summary ....... .... .. .. ... .............. ....................... ..... ... .. ................. 13

A. Transmission of Genetic Materials ................................ 14

l. Gametogenesis and fertilization .............................. 14

2. Discovery of the chromosomes .............. .. ............... 15

a. Chromosomes of domestic species ...... .. .... .. ..... 16

b. Chromosomes and sex determination .. .. .......... 16

3. Nature and functions of genes .............. .... ......... ...... 16

a. The gene ...... .. ..................................................... 16

b. Functions of the gene ............................. .. ......... 18

vi Animal Breeding

B. Principles of Mendelian Genetics ... ...... .......... ... ... .. ...... 19

l. Law of segregation ....... ... ... .......... .......... ... ........ .. ..... 20

2. Law of independent assortment.. ..... .. .... .... ........... ... 21

3 . Probability and tests of genetic hypothesis ....... ..... . 21

C. Gene Effects .... ........ ...... .. ...... ........ .. .. .. ... ... .. .... ..... ........... 21

l. Phenotypic expression of genes ........ ... ... .. .. ... ...... ... . 21

2. Types of gene action .... ... ... .. .... ..... .......... ... ....... ........ 22

a. Additive gene action ...................................... .. .. 24

b. Non-additive gene action ....... ......... .... ..... .. ........ 24

i. Dominance

ii. Overdominance

iii. Epistasis or interaction

3 . Variations in phenotypic ratios ... ....................... .... .. 2 7

a. Linkage (autosomal linkage) ................... ......... . 2 7

b. Sex-related traits .. ... ....... .. .. ... ..... .. ...... ....... ......... 29

i. Sex-linked traits

ii. Sex-influenced traits

iii. Sex-limited traits

c . Multiple alleles .......... .. ....... ...... .... ...... ...... ... .. ..... 32

d . Pleiotropy .... .......... .. .. ... ......... ........... ............. .. ... 33

e. Variable expressivity ..... .......................... .... .. ... .. 34

f. Incomplete penetrance ......... .... .......... .. .......... ... 34

g. Extranuclear (cytoplasmic) inheritance .. .. .. ..... 34

h. Maternal influence ...... .. .. ...... ... ... .. .. .. ... .............. 35

Chapter 3: Genetics of Animal Populations

Summary .. ..... .. ... ....... ... .... ... ... ................ ..... ... ..... .... ...... ..... ... ... 36

A. Genes in Populations ....... ........ ...... ..... ....... ... ...... .. .. .. .. .... 3 7

B. Genetic Specification of a Population ...... .. ... ... .. .... ... .... . 3 7

1. Gene frequency ...... ... .. .. ... ... ..... .. ... ..... ...... ....... ... ...... 38

2. Genotypic frequency .................. ..... .... .... ... .... ..... ..... 38

Contents vii

3 . Computation of gene and genotypic frequencies .... 38

a. When no dominance exists .. ..... ... ........ ..... .... ..... 38

b. With complete dominance .... ....... .. ..... .. ....... .. .... 40

c. Other variations ............ .... .......... .... .. .. .. .... .. ...... . 40

C. Population Dynamics .... ....... .. ...... .... .. .. .. .... .. ... .. ...... .. .. .. .41

l. Static population: Hardy-Weinberg equilibrium ..... 41

2. Dynamic population: Changes in gene frequency ... 43

a. Nonrandom mating .. .. .... ...... ....... ...... ... .. .... ........ 4 3

b. Migration ........... ....... .... .. .. ..................... ... ..... .. ... 44

c. Mutation .. .. .. .... .. .. .. ... ............ .... ..... .. ... .... .. .......... 45

d. Selection ..... ............. ..... ........... .... ... ..... ... ...... .. .. .. 46

e. Small population size ............................ .. .... .. .. .. .4 7

D. Applications of Population Genetks to

Quantitative Traits .. .......... ...... ... .... .... ... .... .. .. ..... ... .. .... .. .. 48

Chapter 4: Quantitative Effects of Genes in Populations

Summary .. ............................. ......... .... .. ...... ........ .... ... ............... 50

A. Values and Means ................................ .. ...... .. ....... .. .. .. .... 51

l. Quantitative traits of possible economic

importance ............ ....... .... .. ........ ... .. ........ .. ... ... .... ..... 51

2. Genetic and environmental effects ..... .... .... .. .. .. .. ..... 52

3. Population mean ....... .. .. .... .. ............. .. ........... ...... .... .. 53

4. Breeding values ............. .. .... .. ..... ..... .. .. .. ..... ..... ... ....... 54

5. Dominance and interaction deviations ........ .. .. .. .. .. .. 55

B. Variance .... ...... .. .. .. ....... .. ...... .. .. ...... .. ............ .. .. ..... .... .. ... . 55

l. Genotypic and environmental variance .. ..... ...... .. .... 55

2. Genetic components of variance ....... ..... .. .... .. ...... .. . 56

a. Additive variance (VA) .. .. ................ .... ........ .. .. ... 57

i. Based on records of a parent and its offspring

ii. Based on sib records

b. Dominance variance (V 0

) .. .. ...... .. ......... .. ........... 58

viii Animal Breeding

c. Interaction variance (V1) •• •••••••• ••• ••• ••• • •• •• • •••• • ••• •• 58

3. Environmental components of variance ..... .... .. ....... 59

C. Resemblance Between Relatives .. ..... ....... ........... ........... . 59

1. Phenotypic resemblance ....... ......... ...... .... ... ...... ... .. .. 59

2 . Genetic covariance ...... ... .... .... ..... .... ..... ... .. ... .. ....... ... 60

a . Offspring and parent ......... ....... ....... ... ..... ... ........ 60

i. Offspring and one parent

ii. Offspring and mid-parent

b. Half sibs .. ........ .... .... .......... ......... .. .. .............. .. .... . 62

c. Fullsibs .. ...... .. ........ ... .. .. .. .. ........... .. .. .. .......... .. .. .. 62

d. Twins .... .. ............. ... .. ... ...... ....... .. ........ .............. ... 63

e. Epistatic interaction .. ...... .............. .. .. ....... .... .... .. 63

3 . Environmental covariance ................................ .. ..... 63

D. Heritability and Repeatability .. .. .... .. ...... .. ...................... 64

l. Concept of heritability .. ..... .. .. ...... .... .. .. .... .... ........ .. .. 64

2. Estimation of heritability .......... ........ .... .... ...... .. .. .... . 65

a . Offspring-parent regression .. .. ........ .. ...... .. .. .. .... . 65

b. Sib analysis ....... .. .......... ...... .......... .. .............. .. .... 66

c. Intra-sire regression of offspring on dam ...... .. .. 6 7

3. Reliability of heritability estimates .. .... .................... 6 7

4 . Repeatability ............. ... .......... .. .. .. ............................. 68

E. Correlations and Interactions ........ .... ...... .. .. .. ...... .. .... .. .. 69

l. Genetic and environmental correlations ......... .. ...... 69

a. Causes of genetic correlation ...................... .... .. 71

b. Estimation of genetic correlation ... ... .. ...... .... .. .. 71

2. Genotype by environment interactions .......... .. .. .... . 7l

a. Definition and examples .. .. ........ .. .... .... .... .. ........ 71

b. Effects on selection ...... .. ...... .. ........ ........ .. .... .. .... 73

F. Statistical Methods to Estimate Genetic Parameters .... 73

Contents ix

Chapter 5: Selection in Farm Animals

Summary .. ..... ........ ........... .. .... .. ...... ... ................... .... .. .... ...... ... . 75

A. Principles of Selection ..... .... ............ .. .... .. ...... ..... ..... ... .... 76

1. Natural and artificial selection ........ ........ ... ... .. .... .. .. 7 6

2. Genetic effects of selection .... ........ .. .... ...... .. ...... ... ... 76

B. Methods of Selection ..... ...... ...... .. .... .... .. ..... .......... ... ... .... 78

1. Individual selection ... ........ .. ...... ....... ... ....... ... ... .... .. .. 79

2. Use of information from relatives .. .... ... .. ... .... ... ... .... 79

a. Selection on the basis of pedigree ... ..... .... ... .. .. .. 79

b. Selection on the basis of progeny tests .... ... ...... 80

c. Selection on the basis of sib information ...... .. .. 81

3. Use of measurements on several traits ... .... ..... ...... .. 82

a. Tandem method ... ... ........ ... .......... .. ... ...... .... ...... . 82

b. Independent culling levels .... .. ..... ............ ..... .... . 82

c. Selection index .......... .. ... .. .. ...... ....... .. .... .. ........ ... 83

C. Selection Index Theory ....... .. .... ..... ....... ..... ... ....... .. .. ... ... 84

1. Genetic and phenotypic variances and

covariances ..... .. .... .... .. ... .... .. .. .... ... ..... ..... .. .. ........... .. . 84

2. Economic values ........ ... ......... ...... .... .... ........ .. .. ......... 85

D. Evaluating Animals by BLUP .. ... ....... .... ..... ... .... .. ... .... ..... 87

l. BLUP animal model .... .. ..... .. ... .. ... .. .... ... ..... ... ...... ... ... 88

2. BLUP versus selection index ... .. .. .. ..... ... ... .. ~ .... ... ... ... 90

3. Comparison of BLUP with other methods

of predicting breeding values .. ....... .... ........ .... ......... . 91

4 . Applications to the local livestock industry ... ........ . 92

E. Estimation of Genetic Progress ..... ... ..... ..... .............. ...... 94

1. Prediction of genetic improvement per year .. ....... .. 94

a. Basic formula ........ ... ............. .... ..... ... ... .... ...... ..... 94

b. Correlated response .... .. ..... ..... ..... .... ... ............ 100

X Animal Breeding

c. Theoretical response possible by current selection methods .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . 10 1

2. Measurement of realized genetic improvement ... 101

a. Methods to monitor genetic improvement .. .. 102

b. Realized genetic improvement in farm

animals ........................ .... .. ............ ... .... .... .... ... 103

c. Long-term effects of selection .......... .. .... ........ 103

d. New developments in statistics and

computing ... ............................................. .... .. . 104

Chapter 6: Systems of Mating

Summary .... .... ... ......... .. .. ........................................ .... ............ 105

A. Inbreeding .............. ............ .. ................ .. ...................... 107

1. Relationship coefficients ....................................... 107

a. Additive relationship ............... .... .. .............. .. .. 108

b. Dominance relationship ......................... .. ..... .. 109

2. Inbreeding coefficient ....................... .................... 110

3. Rate of inbreeding .. ............ .......... ......................... 111

4. Change in genotypic frequency and genetic

variance due to inbreeding .. ........ ........ .... .. .... .. ..... 112

5. How to measure relationships and inbreeding .... 113

a. Tabular method ............................................... 114

b. Path coefficient method .. ................................ 120

6. Consequences of inbreeding .. .. .. .. .. .. .. .. .. . .. .. .. .. . .. .. . 123

a. Exposure of undesirable recessive gene

combinations ............ .. ... .. .. .............................. 123

b. Inbreeding depression ............ .. .. .... ................ 124

7. Practical uses of inbreeding .... ............. ...... .. .... ..... 125

a. Increased prepotency ..................................... 125

b. Detection of lethal genes ............... .... ............. 126

Contents xi

c. Concentrated use of a genetically superior

animal .. .. ... ...... ... ......... ... .. ..... .. ....... ....... ....... .... 126

d. Formation of inbred lines .... .. ... ... ... .... .. .......... 126

B. Outbreeding ..... .. ... .. ..... .... ..... .... ..... .. ......... ...... ..... ........ 128

1. What is heterosis? .......... ..... ...... .. ......... ..... .. .. .. ...... 128

2. Genetic bases for heterosis .. .. .. ...... .... .. .. ...... .... .... . 130

3. How to estimate heterosis ........ .... .......... ......... .. .. . 132

4. Forms of outbreeding .......... .. ... .. .. ...... .. .... .. .... .... .. 136

a. Outcrossing ...................... ......... .. ............. .. .. .. . 136

b. Linecrossing .............. ... .. .. ......................... .. .... 137

c. Crossbreeding .. .. .... .. .. .. .. .. .......... ...... .......... .. ... 138

i. Two-breed crossing (Single crosses)

ii. Backcrossing

iii. Three-breed crossing (Three-breed terminal cross)

iv. Four-breed terminal cross (Topcrossing)

v. Crisscrossing

vi. Three-breed rotation

vii. Four-breed rotation

viii. New breed development

ix. Combining inbreeding, crossbreeding, and selection

d. Grading up .............. .... ...... .. .... ... .... .... .. .. .. ....... 150

e. Species hybridization ................ .. .. .. .......... ...... 151

Chapter 7: Biotechnology Applications for Animal Improvement

Summary ................ ........ .. .... .... .... .... .. .......... ... .. .. ... ... ......... .. .. 153

A. Techniques in Biochemical and Physiological

Genetics ....... ... ...... ... .. ...... ... .. .... ...... ... .. .. ....... ............... 154

B. Techniques in Molecular Genetics (Modern Genetic Engineering) ..... ... .... ........ ..... .... ........... ... ..... .. ..... ..... .... 156

xii Animal Breeding

1. Identification of individuals or genetic groups

and verification of parentage .. .. .. ...... .. ........ .. .... .. .. 156

2. Removal or blocking of undesirable genes .. ......... 158

3. Alteration of structural genes to change product quality ... .. ..... ... .. .. ........ .. ....... ...... ....... ........ ...... .. ..... 158

4. Evaluation of candidates for selection .. .... ........ .. .. 158

5. Transfer of genes .... .. .. ...... .. .. .... ...... .. .. ...... .. ...... ..... 159

C. Techniques in Reproduction or Artificial Breeding .. .. 160

l. Artificial insemination and related technologies .. 161

2. MOET and embryo transfer-based technologies .. 162

a. Pre-pubertal and juvenile MOET .. .... .. .... ...... .. 163

b. Embryo production in vitro ........ .... .......... .. .. .. 164

c. Embryo splitting and cloning ...... .... .... .. .. .... .... 164

d. Predetermining the sex of offspring .......... .. ... 165

e. Induced twinning .. .. .................. .. .... .. .... .. .... .. .. 165

f. Chimeras .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . 166

g. Cryopreservation .. .. .. ........ .. .... .. ...... .. .. .. ........ .. 166

Chapter 8: Animal Breeding Strategies for Livestock and Poultry Genetic Improvement in the Philippines

Summary ...... ........................... .. ........ .. ......... .. ......... .. ... ......... . 167

A. Systematic Approach to the Design of Animal Genetic Improvement Programs .. ........ .. .. .. ...... .... ...... ....... ....... . 16 7

1. Future environments (production and marketing systems) .......... .. ........................ ...... ...... ..... .... .. .. ... . 168

2. Breeding objectives and selection criteria ........ .... 169

3 . Testing and selection program ............ .. ...... .... ...... 170

a. Data collection .............. .... .. .... ...... ........ .... ...... 171

b. Animal performance recording .... .... .. ...... .. .... 171

c. Prediction and reporting of breeding values .. 172

d. Organizing a local selection program .. .... .... .. 173

Contents xiii

e . Importation strategy .......... .... .... .. ...... ........ .... . 174

4 . Crossbreeding systems ........ .. ........ ...... .. .. ............ .. 17 6

5 . Dissemination (dispersal and distribution) of improved breeding stock .. ........ .. .. .. .. .. ...... ...... .. .... 177

6 . Problems and future prospects ........ ...... .... ...... ..... 178

B. Carabao (Water Buffalo) Breeding ........ .. .. ...... .. .. .. .. .. .. 180

1. Industry profile ............ .. ............ .... .. .. .. .... .......... .. .. 180

a . Stock importations .... ............ .. .. ...... ................ 181

b. Philippine Carabao Center (PCC) .. .. .............. 181

2 . Water buffalo breeds .... ................ .......... ...... .. .. .... . 182

a. Swamp buffaloes .. .... .. ................ .. .. ...... .. .......... 182

b. River buffaloes ........ .. .. .... .... ...... ........ .. .... ...... .. . 183

3 . Quantitative traits of economic importance

in water buffaloes .... .... .... .. .. .............. .................. .. 187

4. Selection within purebreds ........ .... .. .. .. ...... ........... 187

5. Crosses between river x swamp buffaloes .. ...... ... 190

a . Heterosis estimates .. ........ .. .. .... .............. .. .... .. . 191

b. Karyotype analysis .... ............ .... .... .. ...... .......... 191

6. Applications of artificial insemination (AI) and embryo transfer (ET) technologies in water buffaloes .. .. .. .. .. .. .. .. .................... ... .. .... ... .. .. .. ..... ..... 192

C. Dairy Cattle Breeding .. .. ...... .... .. .... .. .... .. .. .. ............ .. .... 193

1. Industry profile ............ ........ ................ .. .... .... ........ 193

2. Stock importations and dairy cattle breeds .... ..... 194

3 . Quantitative traits of economic importance

in dairy cattle .. .... .. .. .. ............... ........ ... .... .. .. .. .... ... 196

4. Selection programs .... .. .... .. ................ .. .... .. .... .. .. .... 198

a . AI progeny testing .... ...... .. .. ...................... .... .. . 198

i. Importance of artificial insemination

ii. Test of young bulls program

iii. Sire evaluation

xiv Animal Breeding

b. MOET breeding schemes ................................ 200

c. Open nucleus breeding scheme ...................... 201

i. Foundation selection program

ii. Continuation selection program

d. Response to selection ..................................... 203

5. Crossbreeding of dairy cattle ................................ 203

a. Average genetic difference between Bos

taurus and Bos indicus .. ..................................... 204

b. Heterosis estimates ......................................... 205

c. Genotype (heterosis) x environment

interaction ...... ................... ..... ................... ...... 206

D. Beef Cattle Breeding ......... .... ....................... ...... .......... 207

1. Industry profile ...................................................... 207

2. Stock importations and beef cattle breeds in the Philippines ..... ................................................ ........ 207

3. Quantitative traits of economic importance

in beef cattle .......................................................... 215

4. Selection programs ................................................ 216

a. Improvement within a breed .......................... 217

i. Performance testing

ii. Progeny testing

iii. Pedigree testing

b. Improvement in a commercial herd ............... 219

i. Sire selection

ii. Selection of female replacements

iii. Cow culling

c. Local genetic evaluations ................................ 221

d. Response to selection ..................................... 223

5. Crossbreeding of beef cattle ................................. 223

a. Upgrading ........................................................ 224

Contents XV

b. Commercial crossbreeding .... .. ........ .... .......... . 225

i. Rotational crossbreeding

ii. Terminal crossbreeding

6. Applications of reproductive biotechnologies

in beef cattle .......... .. .................. .. ...... .. .... .. ............ 227

a. Artificial insemination and estrus synchronization ........ .. ................. .... ................ 227

b. Multiple ovulation and embryo transfer .. .. .. .. 229

E. Goat Breeding ........... .. .......... .. .... ...... ................ ... .. ... .. . 229

l. Industry profile ....................... .... .. .. ........ .. ............ . 229

2. Stock importations and goat breeds in the Philippines ... .. ........ .. ................ ... ....... ...... .... .. .. .. ... . 230

a. Performance standards for various goat

breeds .... .. .. .. .......... ................. .. ............. .. .... ... . 232

b. Diversity of goat genetic resources ... .. .. .... .. ... 234

i. Blood protein polymorphisms in native goats

ii. Association between blood protein polymorphisms and mature body weight and external body measurements

iii. Analysis of albumin and transferrin electrophoretic band patterns in different sib families of goats

iv. Geographical distribution of goat blood proteins among Anglo Nubian, native goats and their F

1 crosses

3. Quantitative traits of economic importance

in goats ....... .. ............ .. ... .. ... .. ........ .... .... ...... .. .. ... .... 236

4 . Selection program .. .. .. .. .. .. .. .. .. .. .. .. . .. .. . .. . .. .. .. .. .. .. .. .. 23 7

a . The Philippine Goat Breed Registry .. ... .. ........ 238

b. Local genetic evaluations ..... .... ..... ......... ........ . 238

c. Response to selection .. .. ........ .. .. .... .. ...... ......... 239

xvi Animal Breeding

5. Crossbreeding in goats ... .... ... ... .... ..... ... ...... .... ... .... 239

a . Upgrading ... ...... .... ... ..... ..... .. .. .... .... .. ...... ......... . 239

i. Mature weight and external body measurements

ii. Carcass characteristics

b. Heterosis estimates ......... .. ..... .. ...... .... ... ......... . 241

6. Applications of reproductive biotechnologies

in goats ... .... ... .......... ... .. .. .. .......... ... .. .... .. ........... ..... 242

a. Artificial insemination ..... ..... .. .. ... ........ .. .... .. ... 24 2

b . Multiple ovulation and embryo transfer ....... . 243

F. Swine Breeding ... .. ... ........ ........ .... .. ...... ... .......... ........... 244

1. Industry profile ...... ...... ...... ..... ....... .. ....... ... ..... ....... 244

2. Stock importations ........... .... ....... .... ... .... ......... .... .. 245

3. Swine breeds in the Philippines ..... ... .. ........ ... ... .. .. 246

4. Quantitative traits of economic importance

in swine .. ..... ..... .......... ...... .... .. ... .. ... .......... .... ....... ... 250

5. Selection program ..... .. ...... ......... ..... ... .. ... ..... ......... 252

a . The pyramid structure .. ... ..... ... .. .. ...... .... .. ..... .. 253

b. Home test versus station test ...... ... ................ 253

c. The National Swine Performance Testing Program (NSPTP) ........ ........ ...... ... ..... .. ........... 253

d. Local genetic evaluations ..... ... .... ... .... .. ...... .. .. . 254

e. Locally-derived selection indices .... ........ .... ... . 255

f. Response to selection .. ........ ..... ...... .. ... ...... .. ... 256

i. Results of selection experiments

ii. Recent developments

iii. Other strategies to improve quality of pork

6. Crossbreeding of swine .. ........ ..... .. ...... ...... .. .... ..... . 257

a. Crossbreeding systems ........ ...... ... ........... .. ..... 258

b. Heterosis estimates ..... ... ...... .... ........ ..... .. ... ..... 258

Contents xvii

7. Applications of reproductive biotechnologies

in pigs ............. .... ............ .. ............ .... ......... ..... ....... 260

a. Artificial insemination ...... .... .. .... .... .. .... ...... .... 260

b. Multiple ovulation and embryo transfer ........ 260

G. Poultry (Chicken) Breeding ...... .... .. .. .. .. .. ...... .. .... ...... .. 261

l. Industry profile .. ...... .... .. .. ............ .. ................ .... .. .. 261

a. Production of native chickens .... .. .. .. .. .. ...... .. .. 261

b. Broiler industry .. .. .................. .. ............ .. .. .... .. . 262

c. Layer industry ...... ........ ........ .. .... .. ...... .. .. .... .. ... 262

2. Poultry breeding industry and stock

importation .. .... .. .... ................ ..... ... .... ... .. .. ......... ... . 263

3 . Chicken breeds in the Philippines .............. .. ........ 264

a. Philippine native chickens .... .. .......... .... .. .... .. .. 264

b. Modern chicken breeds .. .. .... .. .... .. ........ .. .. .. .. .. 267

4 . Broiler breeding .. .. .. .. .. .. .. .... ........ .... .... .. .... ...... .... .. . 268

a. Quantitative traits of economic importance

in broilers ... ........... .. ... ............. .... .... .... ..... .. .. ... 268

b. Broiler improvement program ...... ...... .... .... .... 270

i. Testing and selection program

ii. Crossbreeding systems

5. Layer breeding .... .......... .... .................. .... ...... ...... .. . 2 72

a. Quantitative traits of economic importance

in layers ............................... ...... .. ........ .. .......... 2 72

b. Layer improvement program .. .... .... ...... ...... .... 274

i. Multiple-trait selection

ii. Crossing strains or breeds

iii. Elimination of poorer lines, strains, and commercial stocks

H. Duck Breeding ................................ .. ...... ...... .... .... .. .... . 276

l. Industry profile .......... .. .............................. .... ........ 2 7 6

xviii Animal Breeding

2. Stock importation ......... , ........... .. .......................... 277

3. Duck breeds in the Philippines ............................. 278

a . Meat-type breeds ............................................ 278

b. Egg-type breeds ............................................... 2 79

4 . Quantitative traits of economic importance

in ducks ................................................................. 280

5. Selection program ................................................. 281

6. Crossbreeding of ducks ......................................... 283

Chapter 9: Conservation and Use of Domestic Animal Genetic Resources

Summary .. ..................... .... ..... ... ..... ................ .... ... ...... ... ... ..... 284

A. Importance of Biodiversity of Livestock and Poultry Genetic Resources ....... ......................... .... .... ...... ......... 285

l. Present applications .... ....... ........ .... ....................... 285

2. Scientific research ................................................. 287

3. Public sentiment .. .. .. ...... ..... ........ .................. .. .. .. .. . 287

4. Future insurance ................................................... 287

B. Priorities for Conserving Animal Genetic Resources ... 287

C. Kinds of Conservation Schemes ...... .... ... .. ................... 289

l. In situ conservation ............................................... 289

2. Ex situ conservation ..................... ... ...................... 290

3. Recommended conservation methods .................. 292

D. Applied Breeding Schemes for Conservation .............. 293

l. Maintaining genetic diversity ............ .... ........ ........ 296

2. Avoiding/minimizing hazards and genetic loss ..... 296

3. Multiplying the conserved stocks .... ..................... 297

Appendices

2.1. Some notes on probability ......................................... 299

2.2. Test of genetic hypotheses ..... .. ............ ........ ............... 302

Contents xix

4.1. Statistical formulas useful in the study of

quantitative genetics .. .. .......... .. ........ .... ........ .... .. .. ...... 306

4.2. Milestones in quantitative genetics .. .. .......... ...... ...... .. 310

4.3 . Local applications/practice of quantitative

genetics ........ .. ... ........ .... .......... .. .................. ... .... ......... 310

4.4. Milestones in statistical methodology .. ........ .... ... ...... 314

4.5 . Local applications/practice of statistical

methodology ... ...... ..... ............ ............. ........ .. ... .......... 314

5.1. Milestones in selection ........ .. .......... .... ........ ... ........ .. .. 317

5.2. Local applications/practice of selection .. .... .. .. .......... . 318

6.1. Milestones in mating designs .. .. ...... .... ......... .... ...... ... . 322

6.2. Local applications/practice of mating designs ........ ... 322

Practice Questions/Problems

Mendelian inheritance ..... .. ...................... ............ ..... ....... .. 325

Linkage and sex-related traits .. ... .. .................. ........ .... .. .... 328

Laws of probability ....... ..... .... ..... ... .... ..... .... .. ..... ..... .... .... ... 331

Chi-square (X2) test .. .... .. ..... ..... ... .... ....... .. ....... .. .. ..... .. ....... 333

Gene and genotypic frequency ..... .... ...... .. .. .. ...... ....... .. .... .. 334

Effects of selection on gene frequency ...... ........ ...... .. ...... .. 335

Values and means ... ...... .... ............... ..... ....... ...... ...... ...... .... 336

Mean, variance, correlation, and regression .. .. ... .. .. .. .... .. . 33 7

Estimation of heritability .. .. .......... .. ........ ..... ..... .... ... .. ..... .. . 338

Methods of selection for more than one trait.. .... ......... .. .. 341

Prediction and measurement of response to selection ... .. 34 2

Inbreeding ... ......... ............. .. .................. ..... .... ...... ..... ........ . 344

Outbreeding ... .... .... ...... .... .. ...... ........ .... ............... ... .. ... ...... . 345

Operations manual of a livestock breeding

station/center .. .... ... .... ... ...... ........ .... ... .... ...... ... ... .. ........ 348