# Genetic evaluation of claw health traits accounting for potential preselection of cows to be trimmed

Vincent Ducrocq

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Vincent Ducrocq. Genetic evaluation of claw health traits accounting for potential preselection of cows to be trimmed. 68. Annual Meeting of the European Federation of Animal Science (EAAP), Aug 2017, Tallinn, Estonia. Wageningen Academic Publishers, Annual Meeting of the European Association for Animal Production, 2017, Annual Meeting of the European Association for Animal Production. hal-01606238

HAL Id: hal-01606238

https://hal.science/hal-01606238

Submitted on 2 Jun 2020

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Genetic evaluation of claw health traits accounting for potential preselection of cows to be trimmed

I. Croué¹,², K. Johansson³, E. Carlén³, G. Thomas⁴, H. Leclerc¹, F. Fikse³ and V. Ducrocq²

¹Institut de l'Elevage, UMR1313 GABI, 78352 Jouy-en-Josas Cedex, France, ²INRA, UMR1313 GABI, 78352 Jouy-en-Josas Cedex, France, ³Växa Sverige, Institutionen för Husdjursgenetik, SLU, Ulls väg 26, 756 51 Uppsala, Sweden, ⁴Institut de l'Elevage, Chambre régionale d'agriculture de Picardie, 19 bis rue Alexandre Dumas, 80096 Amiens Cedex 3, France; iola.croue@inra.fr

Claw lesions are one of the most important health issues in dairy cattle. Although their frequencies greatly rely on herd management, they can be lowered through genetic selection. A genetic evaluation can be developed based on trimming records collected by hoof trimmers. However, not all cows present in a herd are scored by trimmers. The objectives of this study were to investigate the importance of preselection of cows for trimming, ways to account for this preselection and to estimate genetic parameters of claw health traits. The data set contained 25,511 trimming records of French Holstein cows. Analyzed claw lesion traits were digital dermatitis, heel horn erosion, interdigital hyperplasia, sole hemorrhage circumscribed, sole hemorrhage diffused, sole ulcer and white line fissure. All traits were analyzed as binary traits in a multitrait linear animal model, including only trimmed cows in a seven-trait model (scenario 1), or trimmed cows and contemporary cows not trimmed but present at the time of a visit (i.e. considering that non-trimmed cows were healthy) in a seven-trait model (scenario 2), or trimmed cows and contemporary cows not trimmed but present at the time of a visit, in an eight-trait model, including a 0/1 trimming status trait (scenario 3). For scenario 3, heritability estimates ranged from 0.02 to 0.09 on the observed scale. Genetic correlations clearly revealed two groups of traits (digital dermatitis, heel horn erosion and interdigital hyperplasia on the one hand, and sole hemorrhage circumscribed, sole hemorrhage diffused, sole ulcer and white line fissure on the other hand). Heritabilities on the underlying scale did not vary much depending on the scenario. However including untrimmed cows as healthy caused bias in the estimation of genetic correlations. Scenario 3 seemed to be the best way of dealing with cow preselection, as it accounted for all available information without causing bias.