Genetic Correlations Between Survival and Linear Type Traits Measured in First Lactation

Abstract

Sire evaluations for 173 sires by BLUP for survival to 48, 54, 84 mo, and age at last record from unregistered daughters were correlated with proofs for 14 primary linear type traits and PD type computed by the Holstein Association of America. Progeny tests for type traits were based on first available scores. Genetic correlations between survival or survival adjusted for milk yield and early culling and most type traits were low or antagonistic. Body characteristics especially had low or negative correlations. When the effects of milk yield were removed, foot angle and udder characteristics (except rear udder) had positive genetic correlations with survival. Udder depth and teats rear view had the highest genetic correlations with survival adjusted for yield (near .25). Correlations between udder traits and survival to 84 mo were only slightly reduced by removing the effects of early culling in addition to yield. This suggests that udder characteristics may be useful in selection to reduce involuntary culling even if culling in first lactation is known. In addition to milk yield, selection based on udder depth and perhaps teat placement and foot angle may be justified in commercial dairy cattle.