By Huang, Y. C. and Shanks, R. D., Livestock Production Science, 1995
Description
Heritabilities and repeatabilities of 6 hoof traits were estimated from 10 years of routine hoof trimming data for a research dairy herd. Heritabilities were estimated using a Derivative-free Restricted Maximum Likelihood algorithm with an animal model on original scores and Snell-transformed scores. A sire threshold model was also tested, but was numerically unstable because of the small number of observations per sire. Heritability estimates based on 3821 records of the transformed scores were 0.05, 0.12, 0.06, 0.14, 0.02 and 0.08 for corkscrew claw, heel erosion, interdigital dermatitis, laminitis, sole ulcers and white line separation respectively; the repeatabilities were 0.17, 0.19, 0.15, 0.19, 0.14 and 0.14. Highly consistent estimates were obtained from original scores. Low h2 estimates with a relatively large proportion of permanent environmental variance with respect to additive genetic variance implied that the response to selection for a single score of corkscrew claw, interdigital dermatitis and sole ulcers would be small. Large proportions of environmental variance were consistent with 2 hypotheses: (1) corkscrew claw is affected by other diseases or inappropriate hoof care; (2) interdigital dermatitis or sole ulcers affect some cows repeatedly. Heritability estimates for heel erosion and laminitis were >0.1
Heritabilities and repeatabilities of 6 hoof traits were estimated from 10 years of routine hoof trimming data for a research dairy herd. Heritabilities were estimated using a Derivative-free Restricted Maximum Likelihood algorithm with an animal model on original scores and Snell-transformed scores. A sire threshold model was also tested, but was numerically unstable because of the small number of observations per sire. Heritability estimates based on 3821 records of the transformed scores were 0.05, 0.12, 0.06, 0.14, 0.02 and 0.08 for corkscrew claw, heel erosion, interdigital dermatitis, laminitis, sole ulcers and white line separation respectively; the repeatabilities were 0.17, 0.19, 0.15, 0.19, 0.14 and 0.14. Highly consistent estimates were obtained from original scores. Low h2 estimates with a relatively large proportion of permanent environmental variance with respect to additive genetic variance implied that the response to selection for a single score of corkscrew claw, interdigital dermatitis and sole ulcers would be small. Large proportions of environmental variance were consistent with 2 hypotheses: (1) corkscrew claw is affected by other diseases or inappropriate hoof care; (2) interdigital dermatitis or sole ulcers affect some cows repeatedly. Heritability estimates for heel erosion and laminitis were >0.1
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