Phenotypic relationship between type and longevity in the Holstein breed

The relationship between type traits and longevity was studied in the French Holstein breed using a survival analysis model where the phenotypic value or the estimated genetic value of the cow for each type trait was included as a risk factor. This was done separately for two subpopulations (registered and non registered herds) and with or without adjustment for production traits, i.e., considering true or functional longevity. For all herds, udder traits (and above all, udder depth) clearly influence length of productive life. There seems to be a more drastic voluntary culling on type traits in registered herds. The correction for production traits, as a way to approximate functional longevity, increases the importance of udder traits and decreases the weight of capacity traits. The same results were obtained when the phenotypic value of the cow for type was replaced by her EBV. The relationship between longevity and type traits is most often nonlinear, in particular for udder traits.