Genetic Evaluation of Survival Traits in the Holstein Dairy Cows of Iran

THE longevity is an important functional trait for dairy cow breeders. The aim of this study is genetic evaluation of survival traits in the Holstein dairy cows of Iran. A data set of information from the Iranian Holstein dairy cows was used for this study. The culling date of 36340 animals from 65 herds recorded in 1993-2014 was used. Lifespan and Length of productive life (LPL) were analyzed for longevity. Functional productive life (FPL) was estimated. Production traits consisted of first lactation milk and fat yield. The (Co) variance, heritability and genetic correlation were estimated with multiple-trait REML using an animal model. The mean of lifespan and length of productive life were estimated to be 954(+/- 716) and 1710(+/- 721) days respectively. Heritability of LPL and FPI, estimated as 0.032(0.012) and 0.028(0.012) respectively. The estimates of genetic and phenotypic correlations of milk yield with LPL and FPL were -0.33, 0.20, 0.10 and 0.25, respectively. Due to the decline in length of productive life, with diagnosis of the involuntary culling in herds is possible to increase the longevity.