Indicators of resilience in dairy cattle

KAŠNÁ, Eva., 2024 Indicators of resilience in dairy cattle. In Genetic Days, Conference proceedings. Poland: Genetic Days, s. nestránkováno. ISSN
Year2024
CathegoryOthers
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Abstract

Resilience refers to the capacity of cows to cope with short-term perturbations in their environment. Various disturbances threaten the homeostasis of animals, and their response can, therefore, be observed as fluctuations in frequently measured traits. To indicate resilience, we used 636,823 daily records of activity (minutes per day), body weight (kg) and milk yield (kg per day) of 455 Holstein cows kept on the farm of the Institute of Animal Science in Netluky between 2007 and 2017. For all three traits and each cow, we fitted the curves of predicted performance using polynomial quantile regression. Indicators of resilience were calculated as natural logarithms of variances LnVar of residuals (differences between observed and predicted values), where lower variance indicated good resilience. We used linear animal models for further evaluation. The model included fixed effect of year and season of calving, parity, number of recorded per lactation, random effect of animal, permanent environment and residual. Estimated heritabilities were low, from 0.12 for LnVar(weight) to 0.15 for LnVar(activity). Genetic correlations between traits ranged from 4 % (LnVar(activity)-LnVar(milk yield), LnVar(body weight)-LnVar(milk yield)) to 12 % (LnVar(activity-LnVar(body weight)). Cows with lower breeding values for LnVar(activity) completed more lactations and had shorter interval from calving to conception. The lower breeding values for LnVar(milk) were associated with lower milk yield. Both lower breeding values for LnVar(milk) and LnVar(weight) were associated with shorter interval from calving to conception and shorter calving interval. Supported by the Ministry of Agriculture of the Czech Republic, project QK22020280 and institutional support MZE-RO0723.