Multivariate analysis of phenotypic and genetic correlations between productive and reproductive traits in Holstein dairy cattle

In this study, in order to multivariate analysis of genetic and phenotypic correlations of productive and reproductive traits in Iranian Holstein dairy cows, records of 64220 first lactation dairy cows were used. Data were collected from 749 herds during 1996 to 2009 by the Animal Breeding Center of Iran. The studied traits were productive (305 days milk yield, 305 days fat percentage, 305 days protein percentage and lactation length) and reproductive (dry days, age at first calving, calving interval and open days). Animals breeding values were predicted using a single trait animal model. A canonical correlation analysis using CANCORR procedure of SAS software was carried out to examine the relation between sets of productive and reproductive traits. Analysis indicated that first canonical correlation between first canonical variate pair for phenotypic and breeding values were 0.999 and 0.996, respectively (P<0.0001). Considering high and undesirable genetic correlation between sets of productive and reproductive traits, for long term profitability, designing selection programs based on a combination of these traits is recommendable.