Relationships Among Survival and Linear Type Traits in Jerseys

Daughters of 330 Jersey sires were used to estimate genetic and phenotypic correlations between survival measures and type traits. Survival measures included survival through first lactation, survival to 20 mo after first calving, and length of productive life. Type traits included final score and 13 linear traits. Genetic correlations were estimated by REML from survival of registered cows with type appraisals, from survival of registered cows in herds that did not appraise for type (type data from registered paternal half sisters in appraised herds), and from survival of grade cows in herds that did not appraise for type (type data from registered paternal half sisters in appraised herds). First lactation milk yield (linear and quadratic) was included as covariate. Genetic correlations between survival traits and final score were positive (.21 to .78). Genetic correlations between the survival measures and body traits, rear legs, and foot angle were small or inconsistent across sources of survival data, except for rump angle (less slope tended to be associated with increased survival). Genetic correlations between udder traits and survival were positive (averaged .51) except for udder cleft. Continued selection for improved udder characteristics in Jerseys appears justified.