Daily milk yield variance as an indicator trait in Holstein cattle

KAŠNÁ, Eva, ZAVADILOVÁ, Ludmila a VAŘEKA, Jan, 2023 Daily milk yield variance as an indicator trait in Holstein cattle. In Book of Abstracts of the 31st Symposium Animal Science Days. University of Ljubljana, Biotechnical Faculty: Ljubljana, Slovenia, s. 73. ISSN
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The variability of daily milk yield (DMY) reflects dairy cows‘ energy balance and health status and could therefore serve as an indicator trait for genetic evaluation of health and resilience. Our aim was to estimate the genetic parameters of log-transformed variance of milk yield (LnVar) in the first 100 days in milk and to approximate its genetic correlations with other routinely evaluated traits in Holstein cattle. We used 44,221 records from 683 cows (incl. 658 SNP-genotyped animals) distributed in 4 herds. The single-trait animal model included fixed effects of the farm*season of calving, parity; the first observed DIM, the random effect of animals included in the three-generation pedigree and the random residual. The heritability of LnVar was ⁓0.16. The Person correlations between breeding values showed a favourable association between LnVar and milk yield. The higher LnVar was negatively correlated with protein and fat content; lower body condition score, locomotion, and feet and legs score. The breeding values for higher LnVAR were associated with breeding values for lower fertility and disease resistance (clinical mastitis, hoof disorders). Our study showed that variability in milk yield contained information about cows’ health and fertility and could be used as an early predictor of resilience.

ProjektVyužití genomické selekce pro optimalizaci resilience dojeného skotu, Dlouhodobý koncepční rozvoj výzkumné organizace
OdděleníGenetika a šlechtění hospodářských zvířat