Relationship between conformation traits and longevity in Polish Holstein Friesian cattle

A Weibull proportional hazard model was applied to examine the impact of conformation on true and functional longevity of Polish HF cattle. Lifetime records of 592,639 cows from 2369 herds calving from 1995 to 2008 were used. Conformation data available for 236,137 cows consisted of phenotypic scores for 14 linear traits. True longevity (LPL) was defined as the number of days from first calving to culling or censoring, and functional longevity (FLPL) as LPL adjusted for production. Linear type traits were added into the reference model, which included random effect of herd-year-season, and fixed effects of age at first calving, year-season, parity-stage of lactation, annual change in herd size, and (for FLPL) fat and protein yield. The strongest and positive influence on true longevity was found for udder traits. Capacity traits, rump traits, teat length and rear leg set displayed intermediate optima with respect to LPL. The highest impacts on functional longevity were from udder depth, body depth, chest width, and dairy character. Those traits can be considered early predictors. In respect to FLPL, udder depth had a positive impact, body depth showed an intermediate optimum, and the influences of chest width and dairy character were negative.