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276

TOE ULCER: THE MOST IMPORTANT DISEASE IN FIRST - CALVING HOLSTEIN COWS UNDER GRAZING CONDITIONS

R. Acuña DMV, R. Scarsi DMV, MS, Ph.D.

Summary

Data are reported on foot diseases in dairy cattle. They were obtained from three dairy farms in Uruguay which operated under grazing conditions. Dairy farm 1. There were 850 milking cows including 140 first-calving cows. From these, 59 (42%) showed lameness. After being examined, 37(25%) showed Toe Ulcers in the ir rear legs, mostly affecting the external digit (70%). The remaining lame cows had Interdigital Dermatitis(ID) and Distal Interphalangeal Arthritis(DIA). The cows walked approximately 7 kilometers a day, on a road full of mud and manure. Dairy farm 2. Two hundred and eighty milking cows. There were 43 first–calving cows that presented lameness, and 27 of them were affected by Toe Ulcers. Other lesions were; ID, DIA and Coronary Phlegmons. Sole ulcers were not observed at their typical locations. These cows walked 6-8 kilometers daily. Dairy farm 3. This farm had 520 milking cows. One of us (R.A) was called for assistance because there was a problem of lameness affecting 63 first –calving cows. At the time the veterinarian was called to visit the farm, 20 first-calving cows had already died. Necropsy findings in two of the animals showed extensive phlegmons affecting the back of the leg beginning at the pastern area. The cause of death was septicemia. The remaining 43 affected cows were clinically examined. Toe Ulcers were found in 32(60%) of them, and the third phalanx was extremely detached in 8 cases suggesting fracture or osteitis. Additional lesions found were White Line Disease(WLD), Foot Rot, and interdigital-dermatitis (ID). Cows at this farm walked 6 kilometers daily on roads covered by manure and mud. Preventive trimming was not done at any of the dairy farms. The lame animals sole thickness were less than 3 millimeters. Overgrowth was not observed in any of the cases. It is concluded that the Toe Ulcer is the most serious disease observed in first-calving dairy cows under grazing conditions.

Introduction

There are relatively few reports of sole lesions occurring in zone 1 (Greenough and Vermunt). In a bibliographical review of the topic, some publications referred to toe ulcers and toe abscesses but we believe that this last classification does not fit the lesions observed according to the definition of an abscess. This term does not seem to be the appropriate in relation to lesions occuring in the apex (Kofler).

The aetiopathogenesis of the toe ulcer seems to be related to three main factors: 1) excessive wear of the sole, 2) separation of the axial or abaxial part of the white line in the apex and, 3) downward rotation and advancement of the third phalanx, pinching the solar corium in its anterior part (Van Amstel). However, osteitis of the third phalanx should be also be considered even if there is no apparent or obvious defect in the sole ( Greenough and Bergsten).

Under grazing conditions in which animals are managed by milk producers in South America, where the feeding practices include pasture and supplementation of concentrate feed and corn silage, we have observed that toe ulcers represents the most common lesions in heifers 15 to


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60 days post calving. Two types of toe ulcer lesions are usually presented. One is a single claw horn defect occurring in zone 1 which after further examination, granulation tissue is often observed. This lesion generally responds well to local treatment with hydrogen peroxide and the application of an orthopedic block on the healthy claw. The second type of lesion is more severe and includes bone problems with osteolisis and bone sequestrum, complicated by the anaerobic conditions that are ideal for putrefactive bacteria (Brizzi).

The initial lesions appear within 15 days post-calving, with complications in many cases by day thirty. We observed signs of subclinical laminitis which we believe was serving to complicate the original problem .

The animals in the initial stage of the disease exhibited a slower gait and were reluctant to move. After a few days animals exhibited severe lameness in affected legs with swelling at the coronary band. The lateral claws of hind feet were most commonly affected (70%), but medial hind claws and front feet also had lesions.

Materials and Methods

Three dairy farms with seasonal parturition in the fall (March-April) were studied, with a total of 320 heifers giving birth, of which 165 suffered lameness after 15 to 60 days post calving. Table 1 displays the incidence of the problem. It should be noted that these observations were made during a period of months in which 300 mm of rain fell with an average of 80% humidity. In all the cases the animals walked five kms. daily on roads with plenty of mud and manure. In farms 1 and 3 the heifers were milked separately from the cows. Cows and heifers were milked together in farm 2. In all three operations, acclimatization of the heifers was carried out before calving (on the average twenty days before parturition), with feed and supplements similar to those they would receive after giving birth (corn silage and bran wheat).

Table 1. Occurrence of lameness and toe ulcers in heifers from 3 dairy farms in Uruguay.

FARM HEIFERS LAMENESS TOE ULCER

1 140 59 37 ( 63 % )

2 70 43 27 ( 62,7% )

3 110 63 (-20 ) 32 ( 50,7% )

TOTAL 320 165 96 ( 58,2 %)

Preventive hoof trimming was not performed at any of these dairy operations. A conventional Wopa chute was used to restrain cows for examination and trimming (The Netherlands). The animals were selected for examination according to their symptoms, using the scoring system proposed by Bulgarelli and Van Amerongen. Acepromazine was used to sedate the animals.


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Results Group 1 heifers (at 20 days postpartum) had lesions such as those observed in Pictures 1-a and 1-b, whereas animals in Group 2 (more than 20 days postpartum) exhibited lesions like those displayed in Picture 2. What caught the attention of the authors, was the extreme thinness of the sole (less than 3 mm) exhibited in picture 3.

Picture 1-a Picture 1-b Picture 2 For the treatment of animals in group one, orthopedic blocks (Demotec 85 or Easy Block) were applied. In addition, it was suggested that the animals be rested in a clean dry place for a period of five days. Those in group two were also treated by the application of an orthopedic block and corrective trimming to remove all necrotic tissue. Cotton wrapped in gauze and soaked in hydrogen peroxide were placed on the lesions followed by closure of the lesion with Demotec glue resin.

In those animals which presented with lesions in both digits, Easy Blocks with the toe portion removed were used, but the results were not good. Since it was important that these animals be kept dry and the weather was wet, at a future examination we observed that thirty percent of treated animals presented with hyperextension of the deep flexor tendon in their external digit. Another 30% were sent to slaughter and the remaining 40% presented different alterations with sole ulcers appearing in typical areas.

Conclusions Toe ulcers are the most important lesion in calving heifers under pasture grazing conditions like those practiced in Uruguay, where abrupt nutritional changes are common immediately after calving in autumn with high humidity and rainfall. The initial lesions have a good prognosis if they are treated in time, but lesions with bone compromise have a very poor prognosis. However, according to the analysis of risk factors it is the subclinical laminitis that

Picture 3


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increases the graveness of the condition. The early treatment of the initial lesions proved to be effective, but when lesions involved the bone of the third phalanx, treatment was more difficult and had a poor prognosis. Acknowledgements Nichelle Martin (Writing expressions) for her kind cooperation. Leslie Shearer for her adviser. References 1. Brizzi A. 2001. E-mail communication. 2. Bulgarelli; Van Amerongen, et al. A hind foot position scoring system to monitor sub clinical

lameness in Dutch Holstein Friesian cows. Dept of herd health & Reproduction, Utrecht University, The Netherlands.

3. Greenough P.R., et al. 1990. Laminitis-like changes in the claw of feedlot cattle. Canadian Vet

J 31:202-208. 4. Greenough P.R. 2001. E-mail communication. 5. Kofler J. 1999. Clinical study of toe ulcer and necrosis of the apex of the distal phalanx in 53

cattle. Vet J 157(2):139-147. 6. Miskimins D.W. 1994. Bovine toe abscesses. Eighth Symposium on Disorders of the Ruminant

Digit. Banff, Canada, pp 54-59. 7. Van Amstel S.R. 2000. Toe abscess: A serious cause of lameness in the U.S. Dairy Industry.

XI. Symposium on Disorders of the Ruminant Digit. Parma, Italy; pp 212-214.


280

YIELDING WALKING AREAS IN LOOSE HOUSE SYSTEMS

B. Benz,1 H. Wandel, T. Jungbluth Institute of Agricultural Engineering, University of Hohenheim (440), 70593 Stuttgart,

Germany

Introduction

Lameness, the complex economic and welfare problem in dairy cattle, is directly linked to the flooring in loose house systems (STEFANOWSKA, 1998). Cattle originated on the grass pastures and hill terrain of Europe, where grass pastures and dirt lots provided them with walking surfaces that yielded under the pressure of the hoof (BURGI, 1998). In Germany at present, about 20 % of all cows have to be treated at least once a year due to lameness (ZEDDIES, 1997). Mobility is the most important prerequisite for the smooth functioning of a loose house system. Most disorders are concentrated on the hind legs and, especially, on the outer claw. A closer look at the anatomy of a cow shows, that the hind legs, although suitable for their primary function in forward propulsion, have little ability for shock-absorbance, because they are connected by joints. In contrast, the front legs, that have to catch the propulsive energy, are better designed for this purpose, as they possess an elastic connection to the shoulder blade. The following study aims at creating a farming systems that can, in part, model the original softer footing (grass pastures) environment of a cow without any significant indication of claw disease.

Material and Method

The test is being carried out on two farms, each with 60 dairy cows. Both loose house systems offer comfortable cubicles to avoid prolonged standing. Animal behaviour and claw diagnosis have been recorded, with biological and ethological parameters, in three steps. Firstly, on concrete slatted floors, secondly, on slatted floors covered with rubber mats, and thirdly, again on concrete slatted floors. Slip resistance tests were carried out and confirm the knowledge, that generally, slatted floors older than 5 years have to be seen as being too slippery for cows to walk on. As an appropriate surface material, only compact rubber mats came in question, because they can be cut to fit the slatted floors, and hence do not impede the self-cleaning-function. The elasticity of rubber mats is mainly dependent on the thickness and structure of the bottom side. The top side of the 3 cm thick KSL mats (Gummiwerk Kraiburg, Germany) is covered by a hammer scale profile and the bottom side by conical burls of differing height (see figures 1, 2 and 3). Claw diagnosis, based on region, description and severity, are recorded every three month during claw trimming. Differences in claw sizes are measured to control horn growth. Cow behaviour is observed and floor characterizing parameters, like walking speed, step length, amount of steps per hour, slipping and caudal licking are recorded.

Results and Discussion Claw diagnosis, divided up into 5 severities ranging from 1 (very slight) to 5 (very severe), is the most important parameter for the comparison between hard and yielding floors. Lesions on the wall are inflicted when cows walk and slip on slatted floors leading to an overloading 1 Contact at: Tel: +49-7654-7338l; Fax: +49-7654-77538; E-mail: [email protected]


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of the sole. This can be considered as a predisposing factor for mechanically caused claw diseases, such as laminitis, sole bruises, or even sole ulcers. After installing the yielding rubber mats however, lesions of the wall moved statistically significant from severe to slightly severe. Laminitis is accepted as main risk factor for all the other claw diseases. Although laminitis is a multifactorial problem, it is obvious that yielding floors achieve at least a decrease in sole bleedings. In the white line region, bleedings show an injury of the suspensory apparatus. The pedal bone sinks in the hornshoe and the quick is bruised between sole and bone. Yielding floors moderate the consequences of laminitis, shown clearly by the sinking amount and slightly severity of sole bruises and sole ulcers. After installing the yielding rubber mats, a peeling of the thin layers of the sole horn was observed, which is part of the natural horn growth regulation (see figure 4). This is a positive mechanism, as it indicates that the weight-bearing boarder is assuming the main weight and the sole is carrying only additional weight as the claw sinks on the yielding surface. Consequently, there is no overloading of the sole or typical bruising. In intense dairy cattle husbandry, in contrast to the primordial situation, regularly claw trimming is necessary. Unbalanced weight distribution and local overloading have to be corrected when the horn growth rate exceeds horn abrasion, and natural horn growth regulation is missing. Generally, a moderate horn growth is desired. However, immoderate horn growth is dependent on many factors such as the reaction of heel horn erosion, laminitis, hypertrophy and abrasion. No difference in horn growth was detected between yielding and hard slatted floors. The floors do not only influence claw health but especially animal behaviour. In particular, caudal licking is a valuable characteristic behaviour to observe when determining the quality of the floors, as the animals are in an instable position with one hind leg lifted and the diagonal positioned front leg in danger of slipping. More frequent caudal licking was observed on yielding floors, where the animals licked themselves more than twice and never slipped. When the rubber mats were removed, the animals adapted immediately to the slippery floor (see figure 5). Obviously, the animals renounce their previous behaviour in response to the slipping danger. Not only is the amount of comfort behaviour (caudal licking) observed of importance, but decisive for the hygiene, is also the manner of the movement. Fearing to slip, the animals have little or no confidence in licking. Yet caudal licking might be important for the hygiene between the udder and leg. Step length on yielding floors (about 80 cm) is comparative to pasture and differs evidently to step length on concrete floors (less than 60 cm). Also walking speed increases on yielding slatted floors and statistically significant (81 steps/h (hard floor) and 99 steps/h (yielding floor)) more steps were counted. Conclusions The experiment shows that soft floors favour the requirements for the correct functioning of the claw and unimpeded cow behaviour. Further studies aim to prove that horn quality is strongly dependent on unimpeded locomotion because it is probable that a close relationship exists between the biomechanics, the microcirculation and the nutrition of the living cells that nourish the horn producing tissues of the claw. The advantage of installing the rubber mats is that this one precaution solves two walking area problems in one, namely insuffient slip resistence and floor hardness. Preventing lameness means considerably reducing milk and fertility losses and, as the experiments have shown, investing in a cow’s comfort is definitely profitable in the long term. Not only do economical aspects favour the installation of yielding rubber mats, but also ethical issues are of great importance today, especially amongst


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consumers. Cows mirror their needs quite clearly through their behaviour and this, together with a deeper understanding of their anatomy and physiology, can lead to farming methods that lend themselves better to the original habitat of dairy cows namely, grass pastures. References 1. Burgi K.: Determine maintenance hoof trimming by observing movement. 10th International

symposium on Lameness in Ruminants, Casino Lucerne, Switzerland, pp. 20-22, 1998. 2. Stefanowska J., et al: Impact of floor surface on behaviour and foot lesions in cattle. Rapport 98-

09, Instituut voor Milieu - en Agritechniek, imag-dlo, Wageningen, 1998. 3. Zeddies J., et al: Ökonomische Aspekte des Einsatzes von Tierarzneimitteln und tierärztlichen

Behandlungen. Der praktische Tierarzt 78, Heft 1, S. 44-51, 1997


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Figures Figures 1, 2 and 3: KSL-mat (Gummiwerk KRAIBURG) 1: Bottom view 2:Top view 3: Profile

Figure 4: functional claw Figure 5: Caudal lick

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284

EFFECTS OF A RUBBER-SLAT SYSTEM ON CLEANLINESS, FOOT HEALTH, AND BEHAVIOR IN TIED DAIRY COWS

Christer Bergsten1, Jan Hultgren1

Swedish Dairy Association1, Swedish University of Agricultural Sciences2

Introduction Infectious claw disorders are of great importance all over the world. These diseases are highly dependant on the hygienic conditions in places where the cows stand and walk. The contagiousness of pathogens is also important and infections are more likely to spread in systems where the animals are in frequent contact with each other, e.g. loose housing. The most common contagious claw diseases causing lameness in a UK study were: interdigital phlegmon (foot rot) and digital dermatitis (Mortellaro's disease, hairy heel warts). In total, sole ulcer was the most common disease [5]. However, in Swedish tie-stalls, footrot and digital dermatitis are rarely seen; instead the most common hygiene related diseases are interdigital dermatitis and heel horn erosion [1]. Free-stall systems are rapidly increasing, but still 75% of Swedish dairy cattle are kept in tie-stalls when housed. With less time spent per animal, a higher production and more manure produced, cleanliness and hygiene-related foot lesions is a major problem. In many countries, electric cow-trainers are an efficient means to keep tie-stalls clean from manure and reduce foot lesions. Although foot disorders are of great animal-welfare and economical concern [3], electric cow-trainers were banned by the Swedish animal welfare legislation in 1995, mainly for ethical reasons. Thus, new technical solutions are needed to improve the hygiene in modern dairy systems. A new rubber-slat system for tied dairy cows, with the ability to drain faeces and urine, was studied in a Swedish experimental herd. The aim of the study was to evaluate effects of the rubber-slat system on animal cleanliness, foot health and behavior.

Material and methods

The study included 42 Swedish Red and White cows, which were kept tied in traditional long-stalls (2.20 m) equipped with rubber mats. In a long-stall, the cow can be closed out from the manger, while in a short-stall (1.80 m) she has availability to the manger 24 hours. In 21 stalls, the rearmost 0.74 m of the solid stall floor had been replaced with nine rubber-coated 53 mm wide slats, divided by 29-mm slots (Fig. 1). A similar system had previously been used for more than 20 years in a commercial herd of tied beef cattle. Short (0.50 m) or long (0.85 m) stall dividers were placed between every 2nd cow. The cows were observed during two consecutive housing periods. At the beginning of each housing period, the animals were listed in order of parity and number of days in milk; every 2nd cow on the list was tied on each type of floor (quasi- random allocation). No cows were moved between the floor types during the housing periods and culled cows were successively replaced by heifers in late pregnancy. The cleanliness was assessed weekly (year 1) or bi-weekly (year 2) by observations of the hind part of the body. The extension of contamination with manure was assessed visually. Claw measurements and foot health of the rear feet were assessed at claw trimming in the beginning, middle, and end of each housing period, including the year prior to 1 Contact at: Swedish Dairy Association, P.O. Box 234, SE-532 23 Skara; Tel: +46-511 67000; Fax: +46-511 67134; E-mail: [email protected]


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the study (year 0). Interdigital dermatitis, sole lesions (hemorrhages and/or ulcers) and heel horn erosion were scored (0, 1) by the same person, except for the last trimming of years 0 and 2. The ris ing, lying-down, and resting behavior for 12 matched cow-pairs, one cow from each floor type, were studied during two 24-hour periods, using a time- lapse video technique. The effects of floor type on cleanliness and foot health was analyzed using logistic regression and a GEE technique (GENMOD procedure, SAS Institute Inc., 1997), to account for clustering on the cow level (assuming an exchangeable correlation structure). Statistical analysis of the difference in behavior between the two floor types was done using the Student's t test for matched pairs or the sign test (JMP 3, SAS Institute Inc., 1998). Results The risk of getting dirty on the rubber-slatted floor was significantly lower as compared to the solid stall floor (OR 0.12 for hind feet when short stall-dividers were used, 0.39 for hind legs and 0.38 for thighs and udder). The risk of foot diseases of rear feet at trimming was significantly lower on the rubber-slatted floor (OR 0.23 for dermatitis, 0.09 for heel horn erosion, and 0.34 for sole lesions). The prevalence of dermatitis and heel horn erosion showed a clear seasonal variation, reflecting an effect of time of exposure to imperfect housing conditions (Fig. 2). Cows on the rubber-slatted floor lay down more readily than cows on the solid floor, spending on average 23% less time preparing to lie down (20.8 vs. 27.4 s; P=0.026). Cows on rubber slats also slipped less frequently during rising. There was some evidence of a preference for a solid floor when lying, the relative time spent resting in an adjacent stall being 14% units longer on the rubber slats than on the solid floor (67 vs. 53%; P=0.026). The total average daily resting time was 12.2 h (55.2 min per resting bout). No differences in health (udder health, trauma) were observed between the floor types. Discussion The improved cleanliness on the rubber-slatted floor in the present study resulted in less dermatitis and heel horn erosion, similar to the effect of electric cow-trainers in an earlier Swedish trial [2]. Epidemiological studies have also showed dirtiness to be associated with papillomatous digital dermatitis [6]. The preventive effect of the rubber-slatted floor on sole lesions was unexpected, because the cows were kept on rubber floors in both floor groups. However, it has been proposed that heel horn erosion can provoke sole ulcers, because the support of the bulbs is reduced and the load on the rear part of the sole is greater in a cow affected by heel horn erosion [7]. Moreover, the rubber-coated slats were somewhat elastic in their construction, which might have been beneficial for the lasting of the elastic tissues of the claws, which seem to have deteriorated in cows with sole ulcers [4]. In tie-stalls, long feeding times often make it very difficult to scrape the stalls in pace with the contamination with manure. Although the rubber-slatted floor is rather expensive, this study indicates that its benefits in terms of improved cleanliness and foot health could counterbalance the investment. The cows´ behavior (rising, lying down or resting) was not affected negatively by the rubber-slatted floor system, as has been advocated for electric cow-trainers. The results were found to be in accordance with the requirements of pre-testing of new technical systems and equipment for livestock, as regulated by the Swedish statute on animal protection, and the rubber-slatted floor system has now been approved.


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Conclusions

Tie-stalls equipped with the rubber-slatted flooring improved the cleanliness of the animals and reduced the prevalence of hygiene-dependent dermatitis, heel horn erosion and sole lesions. In the design of future dairy systems, the hygienic conditions of the floors must be considered.

References

1. Bergsten C: Kofot 2000: Promoting hoof trimming and hoof health in Swedish dairy herds. in 2000 Hoof Health Conference. Duluth, Minnesota: American Hoof Trimmers Assoc. 2000.

2. Bergsten C. and Pettersson B.: The cleanliness of cows tied in stalls and the health of their

Hooves as influenced by the use of electric trainers. Prev Vet Med 13:229-238, 1992. 3. Kossaibati M.A. and Esslemont R.J.: The costs of production diseases in dairy herds in England.

Vet J 154:41-51, 1997. 4. Lischer C.J., Ossent P., et al: The significance of the suspensory mechanism of the third phalanx

and its fat bodies in the pathogenesis of sole ulcers in cattle, Part I: macroscopic findings. in 11th Int. Symp. on Disorders of the Ruminant Digit & Int. Conf. on Bovine Lameness. Parma, pp. 222-225, 2000.

5. Murray R.D., Downham D.Y., et al: Epidemiology of lameness in dairy cattle: Description and

analysis of foot lesions. Vet Rec 138:586-591, 1996. 6. Rodriguez Lainz A., et al: Case-control study of papillomatous digital dermatitis in southern

California dairy farms. Prev Vet Med 28:117-131, 1996. 7. Toussaint Raven E., Haalstra R.T. and Peterse D.J.: Cattle foot care and claw trimming.

Ipswich: Farming press. Pp 128, 1985.


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Figure 1. Section of the rear part of the long-stall, showing the rubber-slatted floor over the dung channel with urine drainage. Figure 2. Prevalence of dermatitis and heel horn erosion in tied dairy cows on rubber slatted and solid floors during three housing seasons.

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288

THE LONG-TERM EFFECT OF HOUSING PRE-CALVING ON SOLE AND WHITE LINE HAEMORRHAGES

Laven R.A.,1 Livesey C.T.2

ADAS Bridgets Dairy Research Centre, Martyr Worthy, Hants SO21 1AP 1 Veterinary Laboratories Agency, Weybridge2

Introduction Abnormal hoof conformation results in significant increases in sole and white line lesions (Livesey et al. 2000a). Underfoot conditions have a significant impact on hoof conformation and health. Livesey et al. (2000b) showed that rearing heifers in straw yards resulted in significantly poorer hoof conformation at calving and a significantly higher severity of sole and white- line haemorrhages in the early post partum period. As a result of these findings the examination of these heifers were extended to assess whether the effect persisted into the second lactation.

Materials and Methods Sixty, 12 month-old, heifers were split into two housing groups: Rearing on straw with no access to concrete until after calving or in cubicles during the same period. Both groups were housed in the same cubicle yard after calving (see Livesey et al 2000b for more details). From 12 weeks post partum all had been managed together as part of the main commercial herd at ADAS Bridgets. Thirty heifers were re-examined 40 weeks after calving, 15 at second calving and 30 three months later. Measurements were made of toe angle, toe length, and the prevalence and severity of sole and white- line haemorrhages (Greenough and Vermunt 1994). Results and Discussion The results are summarised in Tables 1 to 3. No significant effects of rearing yard on any parameter were found except on white line haemorrhage score at 40 weeks when the straw reared cows had a significantly lower lesion score. Despite the very large differences seen in the first three months after calving (Livesey et al. 2000b), no effect of rearing yard on hoof conformation was seen. The effect of rearing on lesion score was very similar with no effect on the severity of sole or white line haemorrhages except for a significant effect on white line haemorrhages alone 14 weeks after calving. However, this effect was small compared to that seen after the first calving and was in the opposite direction. These data show that the heifers reared on straw were able to compensate during their first lactation so that there was no significant difference in hoof conformation or haemorrhages after second calving. This suggests that the conclusions of Livesey et al. (2000b) that rearing heifers on soft surfaces is undesirable are incorrect. However, claw horn disease is multifactorial and environment after first calving can have a major impact on lesion development (Livesey et al. 2000a). None of the heifers in this study developed white line

1 Contact at: ADAS Bridgets Dairy Research Centre, Martyr Worthy, Hants SO21 1AP; 01962 779765; E-mail: [email protected]


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disease or sole ulcer, probably because of good management. In a poorer environment, it is probable that exacerbation of the post partum haemorrhages, which were more prominent in the straw-reared heifers, would have led to an increase in claw horn diseases in that group, which would have had long-term consequences. Acknowledgements This research was funded by MAFF References 1. Greenhough P. and Vermunt J.: 8th International Symposium on the Ruminant Digit, Banff

pp.186-96, 1994. 2. Livesey, et al: 11th International Symposium on the Ruminant Digit, Parma pp.137-39, 2000(a). 3. Livesey, et al: 11th International Symposium on the Ruminant Digit, Parma pp.289-291,

2000(b). Table 1: Effect of rearing yard on lesion score, conformation, growth, and wear (mean ±±

SEM) at 40 weeks post partum Lesion score

Housing Sole White Line Toe Angle Toe Length

Cubicles 1.6 (±0.39) 2.0 (±0.32) 40.9 (±0.96) 73.3 (±0.87)

Straw 1.5 (±0.36) 2.0 (±0.37) 43.1 (±0.67) 72.9 (±0.94)

Table 2: Effect of rearing yard on lesion score, conformation, growth, and wear (mean ±± SEM) at second calving

Lesion score


Cubicles 1.0 (±0.37) 0.9 (±0.32) 39.9 (±1.15) 84.3 (±1.46)

Straw 0.2 (±0.17) 1.2 (±0.37) 39.2 (±1.6) 83 (±2.68)

Table 3: Effect of rearing yard on lesion score, conformation, growth, and wear (mean ±± SEM) at second calving + 14 weeks

Lesion score


Cubicles 1.4 (±0.39) 1.4 (±0.22) 45 (±1.4) 84 (±2.0)

Straw 1.5 (±0.36) 0.7 (±0.24) 42 (±1.77) 83.4 (±2.0)


290

THE EFFECT OF ENVIRONMENT PRE-CALVING ON THE HOOF CONFORMATION OF FIRST LACTATION HEIFERS

Livesey C.T2, Laven R.A.1

ADAS Bridgets Dairy Research Centre, Martyr Worthy, Hants SO21 1AP 1 Veterinary Laboratories Agency, Weybridge2

This paper reports the effects on hoof conformation of rearing heifers on straw yards as compared to cubicles. Previous reports have reported the effect on hoof growth and wear, hoof haemorrhages and toe angle. Sixty pedigree heifers were reared from 12 months of age until calving in one of two environments: Straw with no access to concrete or a straw bedded cubicle yard. The hind feet of each heifer were examined at the beginning of the study, mid-pregnancy, approximately six weeks before predicted data of calving and in weeks one and 13 of lactation. In addition to the measurements described previously (Livesey et al 2000), photographs were taken at each examination so that more specific measurements of hoof conformation could be made, including heel depth and toe length. Analysis of these data confirmed the previous analysis which suggested that the hoof conformation of the cubicle reared heifers did not change significantly within the first three months post partum, but the heifers reared on the straw, calved down with hooves that had very different conformation from the cubicle reared heifers (in particular heel height was considerably lower). The hoof conformation of the straw reared heifers also changed significantly during the first three months post partum, becoming much more similar to the conformation of the cubicle reared heifers.


291

INTENSIFICATION OF BUFFALO LEADS TO SIMILAR LAMANITIC LESIONS AS SEEN IN CATTLE

A. Shakespeare,1 M. Hofmeyr2 and C. Bergsten3

Faculty of Veterinary Science, Onderstepoort, South Africa,1 Kruger National Park, South Africa,2 Department of Animal Environment and Health, Skara, Sweden3

Commercial game farming has become big business in southern Africa. Breeding disease-free buffalo, to satisfy this market, not only requires large financial inputs but also various forms of intensification of these animals. These buffalo are often restricted to smallish camps or bomas, not only to protect and isolate them from the elements and disease, but to encourage more successful breeding and survival of the young. Because of this space restriction, natural grazing and exercise is severely limited and supplementary feed has to be offered. Consequently these animals are farmed in far from ideal conditions and certain problems obviously result, with lesions as a result of chronic laminitis being but one. Buffalo calves in one project, born between December 1999 and April 2000 were monitored for just over a year. One batch were removed from their natural mothers at birth and were fostered 3 to a Jersey cow for the entire period. These calves, although still suckling, had ad lib access to lucerne (alfalfa) and eragrostis teff as did their mothers who were also given a total mix ration to sustain their milk production. These calves grew at least a third bigger than the second batch and appeared at lot softer. None of these calves had any hoof lesions although the medial hind claw appeared to rotate slightly inwards. This could be normal and probably corrects itself later and has yet to be recorded. The second batch of buffalo calves were left to suckle their natural mothers until weaning at 5 to 6 months. The calves had had access to ad lib lucern (alfalfa) and eragrostis teff as was offered to their mothers. At weaning, in addition, to the previous diet, the calves were offered ad lib citrus pulp. Within a few months, all these calves showed lesions associated with chronic laminitis such as overgrown hooves (abnormal shapes ie., buckled anterior margin with rising tow; growth rings; high heel and convex sole [as described by Toussant Raven]), sole haemorrhages, slipper foot, double soles and white line bleeding. This second group of buffalo calves were subsequently darted a number of times and curatively trimmed back as close as possible to the normal. A few adult buffalo cows had to immobilized and examined due to lameness. Excessively overgrown hooves had to be trimmed back whilst those with white line disease and sole ulcers once rectified needed to have blocks fixed to the sound medial hind claws. In all these cases, the soft sandy ground and limited area for exercise, plus the commercial diets offered to these wild animals undoubtedly encouraged the hoof problems detected. Economic considerations will preclude the rectification of one or all of the predisposing causes so an increase in hoof problems in buffalo, as seen in cattle, is expected in the future.


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THE INFLUENCE OF HOUSING SYSTEMS AND FEEDING REGIMES ON THE CLAW CONDITION AND THE OCCURRENCE OF KERATINOPATHOGENIC

FUNGI IN FATTENING BULLS

Ch. Stanek, P. Karall, J. Frickh*, M. Keller and J. Spergser

Clinic of Orthopaedics in Ungulates, University of Veterinary Medicine Vienna, Austria, and Federal Research Farm Königshof*, Lower Austria

In central Europe, various housing systems, including older tying stall systems, boxes with solid or slatted floors and in increasing frequency outdoor paddocks, are common for fattening bulls. Also different feeding regimes are applied. Comparatively little is known about the influence of the different systems on the claw condition and on time dependent development of pathological changes. Analyses of the occurrence of keratinopathogenic fungi should lead to a better understanding of the pathogenesis of poor claw horn quality and claw diseases.

60 young Simmenthal bulls, purchased on auctions of the Austrian breeding organisations, were divided into two groups on one large research farm: one group was kept in a tying stall, the other group was kept in an open paddock. Each of these groups was subdivided into two subgroups of 15 bulls each. One subgroup of each housing system was fed a pelleted complete feed ad lib, the other two subgroups were fed with maize silage ad lib and concentrate added. The observation period followed an accommodation period, started on day 75 and ended with slaughter on day 450 of the life of the fattening bulls (Karall, 2001).

Claws were scored using the system proposed by Bosman et al. (1989), modified by Stanek (in Brandejsky et al., 1994). Using this score, factors like condition and contour of the wall, condition and relief of the sole, white line separation, severe pathological changes and heel erosio are recorded for each of the 8 claws and summarised in a single numerical figure, allowing the comparison of a variety of changes. Adaptation of the Boosman score included a higher weighting of severe pathological changes like sole ulcers or apical necrosis of the claw. The bulls were claw-scored 3 times in regular intervals, the 4th claw scoring procedure was performed immediately after the slaughter.

For mycological examination, horn samples are harvested in the coronary region after slaughtering and deep frozen. Thereafter they were cultivated on Sabouraud-glucose agar.

Behaviour data, data on slaughter yield and meat quality factors were analysed as well, but are not included in this report.

The main results of claw scoring are presented in table 1:


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Table 1: Mean values of claw scores and residual standard (se):

SG 1 SG 2 SG 3 SG 4 se

Score 1 16.96 21.67 19.34 13.71 11.38

Score 2 27.48 23.53 15.00 31.46 15.35

Score 3 59.13b 20.39a 62.93b 23.37a 20.93

Score 4 111.23b 23.67a 114.02b 19.18a 21.39

Total score 53.82b 22.72a 53.57b 20.52a 17.77

SG 1: pellets / Tying stall; SG 2: pellets / paddock; SG 3 Maize silage and concentrate / Tying stall; SG 4 Maize silage and concentrate / paddock.

a, b: indicating significant difference p < 0.05

Claw soundness was influenced by various factors. The feeding regime did not affect the claw score during all 4 recordings of the observation period, whilst a significant influence of the housing regime could be observed (SG 1 and SG 3 vs. SG 2 and 4). Fattening bulls kept on tying stalls developed a significant deterioration of the claw condition mainly in the second part of the study. In the tied-stall groups, the claw score increased from mean 18.2 up to 112.4, whilst in the paddock group the increase was significantly lower from 17.7 to 21.4. The most significant deterioration was found with respect to severe pathological conditions, also mainly in the second part of the whole observation period. The occurrence of groove formation on the wall was quite low in both groups. The frequency of solear haemorrhages was quite low under both housing regimes, whilst the frequency of white line separations was significantly higher in the tied stall groups. Despite the frequent removal of manure, heel erosions developed more frequently in the tying stall system in the last part of the observation period. In the bulls kept in the tying stall, the heel erosion score rose from 0.1 to 8.8, whilst in the paddock kept group the increase of changes was comparatively low (from 0.0 to 0.87) Severe pathological changes were observed in the tying stall group in a significant high rate (Severe lesions score 33.5 vs. 7.6 in the paddock group)

Results of mycological examination revealed apathogenic, facultative and keratinopathogenic fungi in a high percentage in both housing groups. 12 different mould fungi and dermatophytes were observed, 8 of them accepted as non-keratinopathogenic in literature. Four keratinopathogenic genera (Alternaria sp., Goetrichum sp., Scopulariopsis sp., Trichophyton sp.) were found. There was no evident correlation with the general condition of the claw. On the other hand, the percentage of claws affected with keratinopathogenic fungi was significantly higher in the paddock group.


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Average daily weight gain was higher in both paddock subgroups compared with the tying stall system (1461 g vs. 1271 g), silage feeding was superior to the complete pelleted ratio. In combination with the superior behaviour possibilities of the paddock group, the paddock system offers a superior economical result, the needs of animal behaviour can be fulfilled much better.

References (a complete list of references may be provided upon request)

1. Boosman R, et al: Arteriographical and pathological changes in chronic laminitis in dairy cattle. Vet Quart 11:144–155, 1989.

2. Brandejsky F, Stanek Ch, et al: Zur Pathogenese der subklinischen Klauenrehe beim Milchrind: Untersuchungen von Klauenstatus, Pansenstatus und Blutgerinnungs-faktoren. Dtsch. Tierärztl. Wschr. 101:68–71, 1994.

3. Karall P: (The influence of two different housing systems and two different feeding systems on claw quality, behaviour, slaughter yield and meat quality in fattening bulls; German) Dr. med. vet. Thesis, Univ Vet Med Vienna, 2001.


295

MANAGING HERD LAMENESS - A PERSPECTIVE FROM DOWN UNDER

J.J. Vermunt1 and D.P. Twiss Institute of Veterinary, Animal and Biomedical Sciences, Massey University, New Zealand

Abstract The management of a lameness problem, involving up to 10 percent of a 500-cow, spring-calving, dairy herd is described. An on-farm investigation identified the farm tracks and the handling of cows by the stock persons as the two main risk factors for this particular problem. Recommendations were made on the patient handling of cows. However, improving the farm tracks had to be postponed until the cows were dried off. Once weekly, the lame cows were observed while walking, locomotion scored and treated (for scores >2).There appeared to be no age predilection. The predominant lesion was septic pododermatitis due to sole or white line penetration. Overall, hind limbs were more often affected than front limbs. The lesions, however, were fairly equally distributed between lateral and medial claws, which reflected the traumatic nature of most of the lesions. Introduction New Zealand has a unique, year-round, pasture-based dairying environment, with an average herd size of well over 250 cows. Lameness causes significant economic losses, and is one of the dairy industry's main welfare issues. The average annual incidence of lameness is around 8-10 percent, varying markedly between herds and between areas. Many herd managers treat cows for lameness themselves, and veterinarians only deal with 25 percent of lameness-causing lesions. Of these, greater than 75 percent are of traumatic origin (Chesterton, 1988; Tranter & Morris, 1991). Major contributing factors to lameness in New Zealand dairy cattle include farm tracks (their length, width, quality, design, construction, maintenance and use), dairy shed yards, the length of time spent on these concrete yards, the manner in which cows are moved from the paddock to the shed, and the manner in which cows are handled during the milking process (Chesterton et al, 1989; Malmo & Vermunt, 1998 & 1999). Nutrition, age, stage of lactation, conformation, genetics and rainfall also play a role, albeit minor (Vermunt, 1992). All these factors need to be taken into account when developing a programme to minimise dairy cattle lameness. This paper describes the management of a lameness problem, involving up to 10 percent of a 500-cow, spring-calving, Friesian dairy herd. Case Presentation Three neighbouring dairy farms had been joined to form one bigger dairy unit using a newly-built, 36-aside herringbone shed. In the spring of 2000, a systematic on-farm investigation identified the farm tracks and the handling of cows by the stock persons as the two main risk factors for this particular herd's lameness problem. Recommendations were made on the patient herding and handling of cows both before and during milking. Although improving the farm tracks was identified as a priority, this had to be postponed until the cows were dried off in the autumn / early winter of 2001.

1Contact at: Massey University, Private Bag 11-222, Palmerston North 5320, New Zealand; Phone: + 64 (6) 350-5329; Fax: + 64 (6) 350-5616; E-mail: [email protected]


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As a rule, lame cows were separated from the milking herd and kept in paddocks adjacent to the dairy shed, so they did not have to walk long distances to pasture. On some days, the total number of lame cows was as high as 50. Managing such a large number of lame cows involved once weekly visits by one or two veterinarians. Cows that had been detected by the farm manager as being lame and that had not been treated before, were observed while walking and a locomotion score allocated (0 = no abnormality of gait; 1 = lameness hardly noticeable; 2 = slightly lame; 3 = markedly lame; 4 = affected limb not or hardly weight bearing). Each cow was examined as she moved on the concrete yard towards or away from the observer for about 10-15 metres at a normal pace. Those with a score of 2 or less were returned to the nearby lame cow paddock to be rested and were milked only once a day. For the other cows, the site of the lameness was determined as they moved around on the concrete. Cases of hind limb lameness were lined up for treatment in the bails of the herringbone shed. Front limb lameness was treated with the cow restrained in a crush. The lame limb was examined and the lameness causing lesion identified by paring away a thin layer of horn from the weight-bearing surface of both digits. The predominant lesion was septic pododermatitis due to sole or white line penetration. Treatment consisted of providing free drainage, removing all necrotic and underrun horn, and applying a Cowslip® to the sound claw. About 80 percent of lame cows had a Cowslip® fitted; some cows needed two on different limbs. The number of animals treated at each visit varied from 6 to 22, and seemed to be positively correlated to the amount of rainfall. There was no obvious age predilection, with both heifers and mature cows being affected. Lame cows were returned to the main herd when the manager considered them completely sound. Antibiotics were administered when lesions were either deep-seated, or if the cause of lameness was interdigital necrobacillosis. Cows that developed septic arthritis of the distal interphalangeal joint were culled. Overall, hind limbs were more often affected than front limbs. The lesions, however, were fairly equally distributed between lateral and medial claws. This reflected the traumatic nature of most of the lesions encountered, being the result of a chance event rather than a systemic condition. Discussion The types of lameness causing lesions are different to those found in most studies carried out in the Northern Hemisphere. Sole bruising and septic pododermatitis due to sole or white line penetration are commonly reported findings in lame dairy cows in New Zealand. The lesions and consequent lameness seen in this herd appear to result from traumatic injury and bruising/infection of the sole corium. The fact that the lesions were fairly equally distributed between lateral and medial claws also adds support to the argument of trauma being the main inciting factor. Under New Zealand conditions, the long distances walked to pasture, wet weather conditions during early lactation, and - in this particular case - excessive walking/standing on hard surfaces and unsuitable materials used for track surface construction are likely to be the major predisposing factors involved. Although the figures of the incidence of lameness in New Zealand dairy herds vary widely between studies (2-38%), there can be little doubt that lameness causes significant economic


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losses to the dairy industry. It is not possible to accurately assess the total loss caused by lameness. In addition to the costs of treatment, milk withdrawal (if required) and extra man hours spent managing lame cows, there are intangible losses such as decreased milk production, reproductive performance and bodyweight, premature culling and replacements costs. A decade ago, Tranter & Morris (1991) assessed the treatment costs to amount to NZ $12.50 per lame cow, excluding extra farm labour input. Evidently, this is considerably less than the mean total cost of Aus $43.00 per case, as estimated by Harris et al (1988) for dairy cattle in south-western Victoria, Australia. There can be little doubt that the cost figure will be significantly higher for the present herd because most lame cows had a Cowslip® applied as a part of their treatment protocol. Therefore, it can be concluded from these figures that steps to reduce lameness will increase farm profitability. The present approach greatly assisted the herd manager in developing a sound understanding of lameness, as it occurs in New Zealand dairy cattle, its treatment, control and prevention, and it could be used as a model for other similar herd lameness problems. References 1. Chesterton RN, et al: Environmental and behavioural factors affecting the prevalence of foot

lameness in New Zealand dairy herds - a case-control study. NZ Vet J 37:135-142, 1989. 2. Chesterton RN: Understanding and dealing with the lame dairy herd. Proceedings of the

Seminar of the Dairy Cattle Society of the New Zealand Veterinary Association, pp.115-125, 1988.

3. Harris DJ, Hebert CD, et al: The incidence, cost and factors associated with foot lameness in

dairy cattle in south-western Australia. Aust Vet J 65:171-176, 1988. 4. Malmo J, Vermunt JJ: Lameness in dairy cattle - A review (part 1). J Aust Assoc Cattle Vet

8:23-31, 1998. 5. Malmo J, Vermunt JJ: Lameness in dairy cattle - A review (part 2) - Farm track construction. J

Aust Assoc Cattle Vet 9:15-18, 1999. 6. Tranter WP, Morris RS: A case study of lameness in three dairy herds. NZ Vet J 39:88-96,

1991. 7. Vermunt JJ: “Subclinical” laminitis in dairy cattle. NZ Vet J 40:133-138, 1992.


298

EFFECTS OF HOUSING PRACTICE AT CALVING AND IN EARLY LACTATION ON THE DEVELOPMENT OF SOLE AND WHITE LINE LESIONS IN DAIRY

HEIFERS

A.J.F.Webster1 University of Bristol, Langford, Bristol U.K.

Abstract

Measurements of claw horn lesions CHL were made on two groups of heifers either introduced to a cubicle house at the time of calving (CC) or housed in a straw yard for 8 weeks after calving then moved into the cubicle house (SC). Lesions increased in both groups to a peak at parturition (P)+12 weeks. There were no differences between groups in white line lesions. However the severity of sole haemorrhages was conspicuously reduced in the SC group and recovery was greater even though both groups were in the same accommodation after P+8. These results strongly confirm the proposition that the severity of CHL can be significantly reduced by minimising external stresses to the foot during the critical period at calving and in early lactation.

Introduction

There is convincing evidence that the severity of claw horn lesions (CHL), presenting as sole haemorrhages (SH) and white line lesions (WL) in dairy cattle is profoundly influenced by external factors attributable to housing and feeding practices. One effective (but often unrealistic) way to reduce these lesions is to house cattle throughout the winter in straw yards instead of in cubicle houses with concrete floors2,4. There is however new evidence to suggest that the primary aetiology of CHL may involve biochemical changes associated with calving and the onset of lactation that compromise the structural integrity in the support apparatus of the foot3. When these are accompanied by substantial external stresses (as in cubicles) this may set in train the sequence of events that proceeds to severe CHL, typically sole ulcers, accompanied by profound lameness. However, if the primary systemic changes in the structural integrity of the foot are, in the absence of external stresses, restricted to the time around calving, it should be possible to reduce the severity of CHL by minimising external stresses during this critical period. This experiment was designed to test this hypothesis by comparing the development of CHL in first-calving heifers either introduced to a cubicle house at the time of calving or housed in a straw yard for 8 weeks after calving then moved into the cubicle house.

Materials and Methods

The trial was conducted with 34 heifers calving for the first time at 2 to 2.5 years of age between October and December. The animals were randomly divided into two groups, matched only according to date of calving. One group CC was introduced to cubicles 4 weeks before parturition (P-4) and remained there throughout the winter. The second group SC was introduced to a straw yard at P-4 and kept there until P+8 after which time they were moved

1 Contact at Department of Clinical Veterinary Science, University of Bristol, Langford, Bristol, U.K. BS40 5DU; Tel: 44 (0)117 928 9459; Fax: 44(0) 117 928 9582; E-mail [email protected]


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into the same cubicle house as the CC group. Both groups received the same ration. Prior to calving the forage was grass silage (36% DM). After calving the forage was a 50:50 mixture of grass silage (36% DM) and maize (corn) silage (28% DM). Concentrates were fed in parlour according to milk yield.

Lesions on the distal surface of each claw were scored using the conventions of Leach et al.1. White line lesions (WL) and sole haemorrhages (SH) were scored on an arithmetic scale of 1 to 8. Heel erosions (HE) were scored on an arithmetic scale of 1 to 3. Cumulative score for sole lesions (CvS), which incorporates both the severity and area of lesions, was calculated as (Geometric lesion score x (Area of lesions/area of foot) x 100) where a geometric score of 1 to 128 equates to an arithmetic score of 1 to 8. The results (Table 1) are presented as arithmetic means of lesion scores for WL, SH and HE but geometric means for CvS. However all lesion scores were normalised by (log10+1) transformation before statistical analysis of variance. Cumulative scores were subsequently categorised on a geometric scale of 1-5 as follows:

Category 1=0-10, 2=11-30, 3=31-70, 4=71-150, 5=>150. In category 1 sole lesions are absent or very minor. Animals in category 5 (severe) all had at least one perforated sole ulcer and were profoundly lame.

Results

There were no differences between the groups CC and SC in milk yield (mean 5,925 litres), body weight (532 kg), condition score (2.7) or mean sole area (57cm2). One animal in the SC group developed environmental mastitis and was withdrawn from the trial. Recorded numbers in the two groups were therefore CC=17, SC=16.

Table 1. Mean lesion scores for heifers in groups CC and SC at four weeks before parturition (P-4) and at 4, 8, 12, 16, and 24 weeks post parturition. Geometric means are given for the (geometric) cumulative scores.

Time (weeks) re:parturition P-4 P+4 P+8 P+12 P+16 P+24

White line CC 0.5 4.9 6.2 5.2 5.0 4.1 SC 0.9 6.0 4.7 3.8 3.7 2.3 Sig,P n.s. n.s. n.s. n.s. n.s. n.s.

Sole haemorrhage CC 1.6 6.2 9.2 12.1 11.6 8.5 SC 0.4 3.1 5.9 5.7 4.1 3.8 Sig,P n.s. 0.046 n.s. <0.0001 <0.0001 0.0049

Cumulative Score CC 1.1 11.5 16.5 59.0 32.7 34.5 (geometric mean) SC 0.8 11.9 10.6 12.8 6.9 5.3

Sig,P n.s. n.s. n.s. 0.002 <0.0001 0.0033 Heel erosion CC 1.7 4.9 5.1 7.7 9.4 10.0

SC 1.5 7.2 7.6 6.3 7.4 6.8 Sig,P n.s. n.s. n.s. n.s. n.s. n.s.

Table 1 summarises lesion scores for WL, SH, CvS and HE at the six times from P-4 to P+24. Fig 1 illustrates the number of animals within each CvS category at these times. Prior to


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parturition sole lesions were absent or very small. All animals were in CvS category 1. By P+4 and most animals showed WL and SH lesions and approximately half the animals were already in CvS category 2 (or higher). However differences between the CC and SC groups were small and, for WL and CvS statistically insignificant. Thereafter SH and CvS scores differed between the CC and SC groups. By P+12 these differences were highly significant and remained so thereafter. Mean geometric CvS was five times greater for the CC group (59/12). Numbers of animals in CvS category 5 were 6 and 1 for CC and SC respectively. In the SC group there was no significant difference in SH and CvS between weeks P+4, P+8 and P+12, despite the fact that these animals were moved from a straw yard into cubicles immediately after P+8. There were however no differences between groups in WL lesions whether analysed at any one time period or by repeat-measures ANOVAR for all periods. There were no significant differences between groups in HE when analysed at any one time period. However repeat-measures analysis across all time periods revealed a highly significant interaction between group and time (P=0.004), indicating that in the SC group, HE values were highest at P+4 and stabilised thereafter, whereas in CC they tended to increase throughout the winter period.

Fig 1. Numbers of animals within 6 categories of cumulative geometric score for sole lesions

at different times with respect to parturition. (light dots = 1; black = 6)

Discussion

These results strongly confirm the proposition that the severity of claw horn lesions can be significantly reduced by minimising external stresses to the foot during the critical period at calving and in early lactation. It is of interest that these differences only involved sole haemorrhages, white line lesions were unaffected. Nevertheless, SH lesions were the major contributor to CvS and to clinical lameness. WL lesions were minor in both groups. This is consistent with the hypothesis that SH (but not WL) lesions are associated with a temporary loss of integrity in the suspensory apparatus of the feet around the time of parturition.

References

Group CC

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1. Leach KA, Logue DN, et al. Claw lesions in dairy cattle: Methods for assessment of sole and white line lesions. Vet J 155:91-102 1998.

2. Livesey CT, et al. The effect of diet and housing on the development of sole haemorrhages, white line haemorrhages and heel erosions in Holstein heifers. Anim Sci 67 :9-16 1998.

3. Tarlton JF, Webster AJF, et al. Biomechanical and histopathological changes in the support structures of bovine hooves around the time of first calving. Vet J (2001 in press).

4. Webster AJF. Effects of housing and two forage diets and the development of claw horn lesions in dairy cows at first calving and in first lactation. Vet J 162:56-65, 2001.


302

THE USE OF BEHAVIOURAL OBSERVATION IN THE IDENTIFICATION AND MONITORING OF LAMENESS

H R Whay,1 A E Waterman-Pearson, A J F Webster

University of Bristol, Department of Clinical Veterinary Science, Langford House, Langford, Bristol, BS40 5DU

Introduction Lameness is a chronically painful condition (Whay et al., 1998a). Although the pain may be most severe, and most obvious, during locomotion, the main welfare problem for the cow is the distress she experiences during the long period of time that she is stationary. The assessment of pain and distress in lame cattle should not therefore be limited to locomotion score alone but should incorporate other behavioural indices of pain and mood observable in stationary animals. This paper describes a set of behavioural observations involving the posture and demeanour of the stationary animals. The observations were evaluated over a 28 day period which encompassed both conventional lameness treatment and administration of parenteral analgesia. Materials and Methods Observations were made on 40 cattle identified as requiring treatment for unilateral hindlimb lameness. In addition to conventional treatment (which included blocking the unaffected claw), the cattle were randomly assigned to receive three injections of either ketoprofen or sterile saline on days 1, 2 and 3. The observer was ‘blinded’ to these treatments. Over the 28 day period immediately prior to and following treatment a series of behavioural observations was recorded (Table 1). These were categorised into observations of posture, appearance/ demeanour, and response to palpation of the lame limb. For the purpose of analysis each observation was classified simply as normal or abnormal. The animals were also locomotion scored within a range of 1 (sound) to 6 (very severe lameness).

Table 1. Classification of behavioural observations of lame cattle Category Observation Normal Abnormal Posture Reluctance to move Moves away easily Reluctant / will not move Straightness of hind limbs Normally straight Abducted / adducted Angle of hocks (lateral view) Normal Reduced angle

Sole placement Sole flat to ground Weight towards heel / toe or medial / lateral claw Evenness of weight bearing Weight evenly distributed Uneven / little weight on one foot Alignment of pin bones Aligned evenly Aligned unevenly

Demeanour General aspect Fidgeting or still Rigid And Response to environment Alert & interested Dull / apathetic

Appearance Head & neck posture Normal (relaxed) Raised / stiff / arched

Ears Normal / alert Still / laid back / down Eyes Observant / making eye contact No eye contact / wide & staring

1 Contact at: University of Bristol, Department of Clinical Veterinary Science, Langford House, Langford, Bristol, BS40 5DU; Tel: 0117 928 9340; E-mail: [email protected]


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Category Observation Normal Abnormal

Response Hock region No response /step away Vigorous stamp / kick To Fetlock region “ “ “ “ “ “ “ palpation Coronary band region “ “ “ “ “ “ “

Results There was a significant improvement in locomotion in response to conventional treatment in both the ketoprofen and saline groups (P=0.001). Table 2 shows the median locomotion scores at each time point for both treatment groups. Figures 1 and 2 illustrate the reduction in abnormal postures over time. Table 2. The scores of locomotion at each observation for both the ketoprofen and sterile

saline groups Treatment

Group Day 1(A)

Initial Observations

Day 1(B) Post Injection

Day 3 Post conventional

treatment

Day 8 1 week post treatments

Day 28 Final Observations

Median Locomotion Scores

Ketoprofen 3 3 2 2 1.5 Sterile Saline 4 3.5 2.5 1 1

Overall, there was no significant difference in locomotion scores between the two treatment groups. Both groups showed changes over time indicative of improvement in posture. The level of improvement was a function of the severity of the initial lameness. Thus the magnitude of change tended to be greater in the saline group, but the initial severity of lameness was also (non-significantly) greater in this group (an unfortunate but unavoidable consequence of the ‘blind’ comparison). The changes in posture that related most closely to the improvements seen in the locomotion score were ‘evenness of weight bearing’, ‘alignment of pin bones’ and to a lesser extent ‘sole placement’. The greatest change in demeanour and general appearance was seen in the head and neck posture and the positioning of the ears. There were no significant changes in responsiveness to palpation.


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The administration of a three day course of ketoprofen did not significantly alter the rate of change of these behavioural observations when compared to the saline group.

Discussion This study of the relationship between pain- induced changes in posture and locomotion develops a theme described by Toussaint Raven (1989). Although this relationship was not unexpected it supports the use of this type of observation in the search for more subtle behavioural measures associated with pain and lameness. Researchers investigating pain management in human patients have used approaches similar to this to rate pain severity in patients, often relying on behavioural observation rather than ‘self report’ by the patient which can be misleading (Richards et al., 1982). More recently, detailed behavioural observation for the assessment of pain in dogs was described by Holton et al. (2001). The changes in head and neck posture of the dairy cattle may be directly related to demeanour or may be at least in part due to changes in stance resulting from lameness The non-steroidal anti- inflammatory drug (NSAID) ketoprofen was not associated with a detectably greater reduction in any of the behaviours than were seen in the sterile saline group. Ketoprofen was, however, shown to cause a modulation in the level of hyperalgesia detectable in this group of animals (Whay et al., 1998b). This suggests that although these observations were not subtle enough to be comparable to the technique of nociceptive threshold testing they were comparable to the sensitivity of lameness or locomotion scoring. Reinforcement of convent ional locomotion scores with other robust indices of posture and demeanour should allow more comprehensive measurement of the effectiveness of treatment and pain management associated with lameness. In addition, further validation of the use of lameness and locomotion scores using concurrent observation of behavioural changes has the potential to be a useful research tool.

-10

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Figure 1. A reduction in the count of observations of abnormal posture shown bychange from initial observation on Day 1(A) in the group which received Ketoprofen.

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Figure 2. A reduction in the count of observations of abnormal posture shown bychange from initial observation on Day 1(A) in the group which recieived Sterile Saline

R2 =0.226P=0.019

Key:Reluctant to Move Straightness of Hind Limbs Angle of Hocks

Sole Placement Evenness of Weight Bearing Alignment of Pin BonesKey :

Reluctance to Move Straightness of Hind Limbs Angle of Hocks

Sole Placement Evenness of Weight Bearing Alignment of Pin Bones


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Acknowledgements The authors would like to acknowledge the funding by MAFF and to thank all the farmers and cows who participated in this study

References

1. Holton L, et al: Development of a behaviour-based scale to measure acute pain in dogs. Vet

Rec 148:525-31, 2001. 2. Richards JS, et al: Assessing pain behaviour: The UAB pain behaviour scale. Pain 14:393-8,

1982. 3. Toussaint Raven E: Cattle footcare and claw trimming. Farming Press (Ipswich), pp 32-3,

1989. 4. Whay HR, et al: The influence of lesion type on the duration of hyperalgesia associated with

hindlimb lameness in dairy cattle. Vet J 156:.23-29, 1998a. 5. Whay HR, et al: The use of Ketoprofen in the modulation of hyperalgesia associated with hind

limb lameness in dairy cattle. 10th International Symposium on Lameness in Ruminants (Lucerne, Switzerland), pp 305-306, 1998b.


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ENVIRONMENT AND MANAGEMENT EFFECTS ON LAMINITIS

Erin Bell1 & Daniel Weary

Animal Welfare Program, University of British Columbia

Abstract

Our epidemiological study had two objectives. The first was to describe the prevalence of laminitis in the Fraser Valley of British Columbia, an area of intensive dairy production. The second objective was to examine among and within farm management and environmental factors that are most associated with laminitis in this area. We recorded the number, severity, and location of laminitic lesions in the claws of 624 primiparous and multiparous Holstein cows from 20 herds during hoof trimming. Lesions were found in cows from all herds. The mean herd prevalence of cows with at least one lesion was 85.7% (with individual herds ranging from 53.7 to 100.0%). The mean herd prevalence of cows with at least one severe lesion (severe haemorrhage or ulcer) was 34.9% (range 7.3 – 74.1%). Within the cow, we found differences in the number of lesions observed on different claws. Cows had more lesions on the hind claws than the front claws, on the hind lateral (HL) than the front lateral (FL) claws, on the HL than the hind medial (HM) claws, and on the front medial (FM) than the FL claws. Within the medial claws there was no front-hind difference (i.e. HM and FM). Overall, the HL claws contained 54.9% of the lesions followed by the FM (17.7%), the HM (16.4%) and the FL (10.9%). We found a very similar pattern when considering only the most severe lesions, except that the difference between the FM and HM claws was significant in this analysis. Focusing on the distribution of lesions within the claws, zones (adapted from the recommendations of the VIth Symposium on Diseases of the Ruminant Digit, Liverpool, 1990) differed in the total number of lesions, with the greatest number in Zone 4. Of the 2116 lesions observed, 47.1% were located in Zone 4, 26.8% in Zone 3, 14.2% in Zone 5, 7.9% in Zone 2, and 4.0% in Zone 1. Once again, we found a very similar pattern of results for the most severe lesions. Primiparous cows were at greater risk for laminitis at the beginning of their lactation while multiparous cows were more likely to have visible lesions in mid- lactation. Overall, cows with higher body condition scores were less likely to have laminitic lesions than those with lower scores. Relationships between management and environment factors and lesion scores are also discussed. In conclusion, laminitis affects the majority of dairy cows in the Fraser Valley. The risk of lesions is related to stage of lactation, individual cow factors and farm characteristics. Keywords: dairy cattle, laminitis, lameness, hoof, barn design, herd management

1 Contact at: Faculty of Agricultural Science, University of British Columbia, 2357 Main Mall, Vancouver, Canada BC, V6T 1Z 4; 604-822-1422; E-mail: [email protected]


307

BOVINE LAMENESS IN PORTUGUESE DAIRY FARM - EFFECT OF HOUSING, PRODUCTION LEVEL AND FEEDING SYSTEM ON BOVINE LAMENESS

A.N. Brito1 and J.C.O. Lopes

Instituto Politécnico de Viana do Castelo, Escola Superior Agrária de Ponte de Lima, Portugal The problems prune was identified as one of the largest problems in the exploitations aimed for milk production, in the Entre-Douro and Minho. This area, with enormous weight in the agricultural context of Portugal, more specifically in the milk sector, has been suffering a great restructuring, through larger production intensification, animal number increase and the abandonment of small producers, being, in this moment, this sector extraordinarily vocational and of great relevance to regional economy. In an initial phase of the study, 80 inquiries to producers of the area, were executed, the producers with best medium/larger milk production in the year of 1998-1999, with the identification of the largest strangulations, besides causes and the most relevant lameness pathologies (Brito & Lopes, 2000). It was considered, still, the inherent losses to this pathology for the group of the exploitations, as well as the proposal of a prophylactic program. With base in the effects considered significant (P<0.05), in other words, housing type, production level and concentrate tenor, 20 explorations has selected, with different characteristics for each one of these effects, in the sense of if they identify incidences and own pathologies, that, eventually, she can attribute to each one of the proposed causes. On the other hand, it is intended, still, to esteem the economic losses (for refuse, treatments or production reduction), as well as the impact of the prophylaxis measures proposed and/or already accomplished in the exploration. The work is in conclusion phase, and the first results confirm the previous presuppositions (relevant effect of the housing, feeding and productive level) and it is waited for the conclusion and writing until September.


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DISASTERS WITH FREE-STALL DESIGN – FOUR CASE EXAMPLES

N.B. Cook,1 K. Nordlund University of Wisconsin-Madison, School of Veterinary Medicine

Four examples of free-stall design and management problems will be presented. Herds were referred to and visited by the Farm Animal Production Medicine Team from the University of Wisconsin-Madison, School of Veterinary Medicine. For each scenario:

I. Color pictures will be used to depict the problem II. Stall dimensions and bedding type will be clearly shown III. Associated cow health problems will be summarized IV. A Cow Comfort Index will be given V. A diagnosis will be suggested VI. A solution to the problem will be described

A general principle by which free-stall design may be assessed will form the basis of the poster presentation.

1 Contact at: 2015 Linden Drive West, Madison, WI 53706-1102; 608-265-4981; E-mail: [email protected]


309

BEHAVIOURAL INDICATORS OF PAIN ASSOCIATED WITH LAMENESS IN DAIRY CATTLE

K.A. O’Callaghan,1 R.D. Murray1 and P.J.Cripps1

1Department of Veterinary Clinical Science and Animal Husbandry, University of Liverpool, Leahurst, Chester High Road, Neston, South Wirral L64 5TE

Introduction Lameness is a debilitating condition in which the affected animal attempts to reduce the weight borne by a particular limb. Foot lesions cause approximately 90% of cattle lameness. Most lesions occur on the lateral digit of the hind foot. Pain is a serious component of lameness, which is often masked by the instinctively stoical nature of cattle. This leads to delayed detection of lameness and results in treatment without due acknowledgement of the pain experienced by the cow. Behavioural observations are useful for gaining insight into how an animal copes with its environment and imposed stresses. When the pain experienced by the cow during locomotion is sufficiently great obvious lameness can be detected and treated. However, lame cattle adopt several pain-related behavioural changes to redistribute weight or minimise discomfort in the early stages of the condition, and for the duration of the episode. These changes are often ignored. Spinal arching, lowered head carriage and rotation of the digits are among the behaviours used by the cow to alleviate the pain of lameness. These have been validated in terms of repeatability, inter-observer consistency and association with the presence of lesions on the feet. Study Objectives - To investigate the reliability of behavioural indicators as predictors of foot lesions in dairy

cattle - To encourage those dealing with cattle to recognise these indicators and act promptly Materials and Methods A normal cow walks with a level spine. She selects a path around obstacles. She places her hind feet almost exactly onto the same spot as the fore feet. The gait appears comfortable and she walks at an even pace. The feet point in the direction of travel. Method 1: Behavioural Scoring System • A behavioural scoring system was developed to assess the posture adopted by cattle

during locomotion. • Six behaviour categories were selected. Each was scored using a Numerical Rating Scale

between 1-5. (NRS 5). 1 = Normal, 5 = Most severely abnormal. • Cows were observed walking past and then away from the observer on a level concrete

surface. Behaviours scored were:

1 Contact at: University of Liverpool, Division of Farm Animal Studies, Department of Veterinary Clinical Science and Animal Husbandry, Leahurst, Neston, S. Wirral CH64 7TE; Phone: +44 (0) 151 7946024; E-mail: [email protected]


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1. Overall locomotion score 4. Tracking – hind feet on fore feet positions 2. Spine curvature 5. Head carriage 3. Speed 6. Rotation of feet from the direction of travel • Inter-relationships of the behavioural categories was assessed using Spearman rank

correlation tests Method 2: Assessment of the repeatability of the behavioural scoring system • Scores attributed to cows on successive days by a single observer were assessed for

repeatability • The degree of agreement and near-agreement between scores provided a simple measure

of repeatability (Near- agreement was defined as being within one score on the 1-5 scale) Method 3: Assessment of inter-observer consistency of behaviour scoring • Two observers scored cows independently according to the NRS 5 guidelines • Differences between the observer scores for individual cows were assessed • Repeatability was evaluated on the basis of percentage agreement and near-agreement as

above Method 4: Validation of behavioural changes as indicators of pain due to digital disease • All cows had their hind feet trimmed using the five step ‘Dutch Method’ • Details of lesions present were recorded along with treatment or further action • Lesion status was compared against the behavioural scores attributed before foot trimming Results Inter-relationships of the behavioural categories. - Locomotion scoring is a widely accepted method of lameness assessment. All behaviours were correlated against the overall locomotion score. • Non-parametric data - Spearman rank correlation test carried out • Highly significant relationships between all behaviours and locomotion scoring

Table 1. Correlation between overall locomotion score and selected behaviours Behaviour Correlation coefficient Significance (P) Spine : locomotion score 0.69 < 0.001 Speed : locomotion 0.68 < 0.001 Tracking : locomotion 0.75 < 0.001 Head level : locomotion 0.70 < 0.001 Rotation : locomotion 0.82 < 0.001

Repeatability of the behavioural scoring system • High levels of agreement and near-agreement between scores attributed to individual cows

on successive days by a single observer.


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Table 2. Intra-observer repeatability of behavioural scores

Behaviour Agreement (%) Near agreement (%) Locomotion score 70 (49) 116 (82) Spinal curvature 50 (36) 119 (86) Speed 27 (50) 47 (87) Tracking 11 (28) 30 (77) Head carriage 21 (46) 35 (76) Rotation 9 (29) 21 (68)

Assessment of scoring consistency between observer • High levels of agreement and near-agreement for all behaviours • Indicates ease of training and usage of the system

Table 3. Inter-observer consistency of behavioural scores Behaviour Agreement (%) Near agreement (%) Locomotion score 30 (37) 66 (81) Spinal curvature 40 (49) 74 (91) Speed 25 (36) 57 (81) Tracking 24 (39) 50 (81) Head carriage 23 (43) 47 (87) Rotation 17 (33) 43 (84)

Validation of the behaviours chosen to indicate digital pain or disease • Strong correlation between behaviour and the presence or absence of lesions on the feet • Supports the use of these behaviours as indicators of the development or presence of

lameness and pain due to foot lesions

Table 4. Relationship between behaviours and the presence/absence of foot lesions

Behaviour (v) lesion Correlation coefficient Significance (P)

Loco : lesion present 0.52 < 0.001 Spine : lesion present 0.55 < 0.001 Speed : lesion present 0.43 < 0.001 Tracking : lesion present 0.45 < 0.001 Head level : lesion present 0.38 < 0.01 Rotation : lesion present 0.50 < 0.001

Conclusions These behaviours can be reliably used to indicate pain and discomfort due to the presence of foot lesions. Improved awareness and recognition of these behaviours by veterinary surgeons and stockmen on farms will increase early lameness detection rates and therefore enable rapid, effective treatment. Good repeatability and levels of agreement between observers indicate how easily the system is learned and applied in practice. Awareness of all the behaviours identified is important since individual cows often adopt different combinations. A subtle change in one or more behaviours is often seen in cows that on first impression appeared sound.


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Acknowledgements The authors would like to thank the RSPCA for the funding associated with this research. Also, staff at Clayley Hall Farm and colleagues in the Department of Veterinary Clinical Science and Animal Husbandry for their help and advise in the development of this work. Particularly: Dr. W.R. Ward; Miss E. Cabell; Mr J. Hughes.


313

COW COMFORT IN LOOSE HOUSE SYSTEMS

H. Wandel,1 T. Jungbluth and B. Benz Institute of Agricultural Engineering, University of Hohenheim (440), 70593 Stuttgart,

Germany Cow comfort in loose housing systems is no luxury, but a necessity. Increased return can only be achieved permanently in a loose housing system that offers more cow comfort. Diseases of the integument and claws, caused by incorrect housing conditions, can be prevented based on experimental findings. Animals require more room when they lie down to when they are standing, therefore cubicle constructions must be made to fit the cow. Cubicle detachments must stand off the floor at approximately 0,70 to 0,80 m. the cows should not bump into the sides when getting up or lying down. The cubicles should not only provide sufficient lying room (1,70 –1,80 m long und 1,20 –1,25 m wide) but should also be soft. Soft mattresses (12 to 15 cm thick) are preferred by the animals. They induce the cows to assume their natural rhythm of resting for about 90 minutes in their favoured position between 10 to 12 times a day. At the same time, the elastic, yet yielding deformation of the thick mattresses supports the sensitive legs and joints the cow is resting on. Inadequate lying comfort leads to very long standing periods and this in turn favours an overloading of the claws. In addition, short lying periods shorten the ruminating phases significantly. If the animals lack the confidence of moving around freely in the lying areas, they try to avoid getting up regularly which leads to an inferior feed intake and consequently has a negative effect on their milk production. The walking areas should correspond to the needs of the cow. By nature, the claw is designed for walking on a yielding underground, therefore the walking areas should be soft. This soft underground can be reproduced artificially using elastic rubber mats on the concrete or slatted floors. A soft surface is not slippery and enables unimpeded movement, as well as essential social and comfort behaviour amongst the cows. Pastures encourage the cows to move about at ease and lick themselves clean particularly between their hind legs in the area of the udder, and so prevent the appearance of painful eczema. Not only do the soft floors lead to an increase in licking, but also to a marked decrease in claw disease, with no more severe cases noted. The reasons are undoutedly that, due to the softer flooring, the weight bearing boarders of the claw carry the main weight. Cow comfort in cubicles and walking areas guarantees the desired animal behaviour and avoids damage of the integument and claw at the same time. If the structural environment is animal friendly, it is marked through "minimal barn, but maximum comfort ".

1Contact at: TEL: +49-711-4592504; Fax: +49-711-4592519


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DIFFERENCES IN MECHANICAL PROPERTIES OF THE HOOF HORN OF HEIFERS BEFORE THE FIRST LACTATION

Betina Winkler,1 Jean K. Margerison and Charles Brennan

University of Plymouth, Seale-Hayne Faculty, Devon, UK1

Introduction Increases in the number and severity of claw horn lesions on dairy cows and heifers are related to the time around calving and the start of the lactation period. The hind outer claws are the most affected claws when compared to the hind inner and front claws, suggesting an overburden of these claws (Vermut and Greenough, 1996; Offer et al., 2000; LeFevre et al., 2001). However, the factors responsible for the development of lesions are not well defined. This paper aims to describe differences in the elastic modulus and puncture resistance observed in the hoof horn of heifers one month before calving. Materials and Methods Mechanical tests were performed on samples of hoof horn of the sole taken from 20 heifers at one to two months before calving. The heifers were kept at pasture and joined the lactating cow group one month before calving to get accustomed to handling in the milking parlour. Samples of hoof horn were collected using a plain. The first outer layer (0.5mm) of the horn of the sole and white line of the distal part of the hoof of all claws was discarded and a sample of 0.05 to 0.3 mm thickness was kept for analysis. Samples were kept in sealed plastic bags and stored in a refrigerator at a temperature of 3 - 5 °C until analysis the following day. Samples were analysed for puncture resistance using a P/2N needle probe and a tension test was performed using self- tightening roller grips for the calculation of the elastic modulus (EM). Both tests were performed on a TA.XT2i texture analyser (Stable Micro Systems). The samples used for the tension tests had the following measurements: 10mm x 15mm x thickness (0.05-0.3 mm). Three to five puncture tests and one to two tension tests were completed on the sole and white line areas of each claw. The dry matter of the samples was measured by oven drying at 100°C for 72 hrs. The data was analysed by ANOVA – GLM (Minitab 12.0), using cow, claw and period as fixed effects and thickness as a covariant. The effect of thickness on puncture force was tested by regression analysis. Means with significant p values were compared using Tukey test (95 % confidence interval). Results Sample thickness had a significant effect on the force required to puncture the sample (p<0.001). Thicker samples required a greater force to be punctured. Puncture force was corrected for sample thickness using the following equation: y = 494.41 + 3440.1 x (R2 = 0.411).

The mean values for dry matter, puncture force of the sole and white line horn and EM of the front and hind claws, are presented in Table 1.

1 Contact at: Department of Agriculture and Food Studies, Seale-Hayne Faculty, Plymouth University, Newton Abbot, Devon, TQ12 6NQ, UK; (1626) 325681; Fax: (1626) 325605; E-mail: [email protected]


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There was no significant difference between the dry matter of the hind and the front claws.

The puncture force of the sole horn was significantly greater in the front claws when compared to the hind claws (p<0.01). The puncture force of the white line did not differ significantly between front and hind claws. However, it was correlated to the puncture force of the sole (0.46, p<0.01). There was no significant difference between the puncture force of the sole horn of the inner and outer claws on both the front and hind hooves. The same finding was found to apply to the white line horn. The puncture force of the sole horn was significantly different between heifers (p<0.01). The elastic modulus of the sole horn was significantly greater for the front claws when compared to the hind claws (p<0.05). There was no difference in the elastic modulus of the white line between front and hind claws. No comparison of elastic modulus was made between the inner and outer claws.

Discussion

The difference in the puncture resistance between the front and hind claws can not be attributed to a difference in dry matter, unlike findings reported by Zoscher et al. (2000). The heifers were at pasture when tested, therefore they were less susceptible to changes in the moisture of the environment around the claws (cows standing with the hind claws in passageways and front claws in cubicles).

The force required to puncture the white line horn was lower than the force required to puncture the sole horn, agreeing with the findings of Mulling et al. (1994) that demonstrated that the white line is less hard when compared to the sole horn.

Tranter et al. (1993) demonstrated that the occurrence of lesions could be related to mechanical properties of the hoof horn. The differences in puncture force and elastic modulus observed between the front and hind claws are considered to be related to the biomechanics of the claws. According to Bergsten (2001) and Toussaint-Raven (1985) the front claws bear more weight than the hind claws. However, the cow can relieve the pressure of the front claws easier than the hind claws through postural adaptations (Toussaint-Raven,1985). MacCallum (1999) demonstrated that an increased pressure on the hoof increases the rate of cell proliferation and protein synthesis, affecting the structural conformation of the hoof horn. The observed differences between front and hind claws helps to explain why front claws are less affected by the appearance of haemorrhages during lactation.

No differences were observed between the force required to puncture the inner and the outer claws, indicating no differences in the structure of the hoof horn of the sole of the inner and outer claws at one month before calving. The development of the udder around the calving period of the first lactation is considered the major predisposing factor to cause a shift in load bearing to the outer hind claws (Vermut and Greenough, 1995). The hoof horn analysed at one to two months before calving would have been produced around mid pregnancy and at this time the udder was not exerting enough pressure on the hind legs to cause the shift in load bearing. Tranter and Morris (1992) described changes in sole concavity and hoof wear in 2-year-old heifers two months before calving and after calving. After calving there was a significant loss of concavity of the sole and the loss of concavity was greater in the outer hind


316

claws. According to theses authors the change in concavity was a direct consequence of wear exceeding growth and the wear of the hoof wall and sole horn was greater in the hind outer claws when compared to the hind inner claws.

Conclusions One to two months prior to calving the heifers demonstrated a higher puncture force and elastic modulus on the sole horn of the front claws when compared to the hind claws. These differences increase the susceptibility of the hind claws to the development of lesions during calving and the start of lactation. No significant difference in puncture resistance was found between the inner and outer claws. Differences between the inner and outer hind claws are believed to develop around calving, when the pressure exerted by the udder causes a shift in load leading to an overburden of the outer hind claw. References 1. Bergsten C. Effects of conformation and management system on hoof and leg diseases and

lameness in dairy cows. Vet Clinics N Am – Food Anim Pract 17:1-23, 2001. 2. Le Fevre A.M., Logue, et al. Correlations of measurements of subclinical claw horn lesions in

dairy cattle. Vet Rec 148:135-138, 2001. 3. MacCallum A.J. A cell biological approach to study lameness in dairy cows. Glasgow, University

of Glasgow, 1999. 4. Mulling Ch, Bragulla H., et al. Structural factors influencing horn quality and sites of predilection

at the ground surface of the cattle hoof. Schweizer Archiv fur Tierheilkunde 136: 49-57, 1994. 5. Offer J.E., McNulty D.N., et al. Observations of lameness, hoof conformation and development of

lesions in dairy cattle over four lactations. Vet Rec 147:105-109, 2000. 6. Toussaint Raven E. Cattle footcare and claw trimming. Farming Press Ltd., Suffolk, UK, pp.126,

1985. 7. Tranter W.P. and Morris R.S. Hoof growth and wear in pasture fed dairy cattle. NZ Vet J 40: 89-

96, 1992. 8. Vermunt J.J. and Greenough P.R. Structural characteristics of the bovine claw: horn growth and

wear, horn hardness and claw conformation. British Vet J 151:157-180, 1995. 9. Vermunt J.J. and Greenough P.R. Sole haemorrhages in dairy herds managed under different

underfoot and environmental conditions. British Vet J 152:57-73, 1996. 10. Zoscher M., Hinterhofer, C, et al. New aspects of mechanical properties of bovine hoof horn.

Proceedings of the Eleventh International Symposium on Disorders of the Ruminant Digit, 3-7 Sept. 2000, Parma, Italy, pp. 91-93, 2000.


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Table 1: Puncture force (N) and Elastic modulus (N/mm2) of the sole horn and the white line horn of front and hind claws and dry matter (%) of front and hind claws

Claws front hind sem P

dry matter 74.70 75.06 0.45 Ns

puncture force

-sole horn 8.441b 7.359a 46.55 0.01

-white line 5.908 6.236 40.8 Ns

Elastic modulus

-sole horn 92.8b 86.8a 15.35 0.05

-white line 101.0 100.2 38.7 Ns


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