Including milk production, conformation, and functional traits in multivariate models for genetic evaluation of lameness

摘要

Lameness is a serious health and welfare issue thatcan negatively affect the economic performance of cows,especially on pasture-based dairy farms. However, mostgenetic predictions (GP) of lameness have low accuracybecause lameness data are often incomplete as data arecollected voluntarily by farmers in countries such asAustralia. The objective of this study was to find routinelymeasured traits that are correlated with lamenessand use them in multivariate evaluation modelsto improve the accuracy of GP for lameness. We usedhealth events and treatments associated with lamenessrecorded by Australian farmers from 2002 to early 2019.The lameness incidence rates in Holstein and Jerseycows were 3.3% and 4.6%, respectively. We analyzedthe records of 36 other traits (milk production, conformation,fertility, and survival traits) to estimate geneticcorrelations with lameness. The estimated heritability± standard error (and repeatability ± standard error)for lameness in both Holstein and Jersey breeds werevery low: 0.007 ± 0.002 (and 0.029 ± 0.002) and 0.005± 0.003 (and 0.027 ± 0.006), respectively, in univariatesire models. For the GP models, we tested includingmeasurements of overall type to prediction models forHolsteins, stature and body length for Jersey, and milkyield and fertility traits for both breeds. The averageaccuracy of GP, calculated from prediction errorvariances, were 0.38 and 0.24 for Holstein and Jerseysires, respectively, when estimated using univariate siremodels and both increased to 0.43 using multivariatesire models. In conclusion, we found that the accuracyof GP for lameness could be improved by includinggenetically correlated traits in a multivariate model.However, to further improve the accuracy of predictionsof lameness, precise identification and recordingincidences of hoof or leg disorder, or large-scale recordingof locomotion and claw scores by trained personnelshould be considered.