Estimates of Genetic Parameters for Body Weight in Turkish Holstein Bulls using Random Regression Model

Abstract

The objective of this study was to estimate genetic parameters for the body weights of Turkish Holstein bulls usingthe random regression model. The data set consists of 1475 body weight records from 395 Holstein bulls raised in thesame herd. Body weight records of bulls aged between 32 and 725 days old were collected at approximately two-monthintervals from December 2013 to October 2014. In the study body weight measurements made on the same day wereaccepted as a group and the bulls were grouped into 10 different groups according to their age. The additive genetic andpermanent environmental effects were estimated using DFREML algorithm by third order Legendre polynomials. Theadditive genetic variance estimates ranged from 10.73 to 4867.07, the phenotypic variance estimates ranged from 382.84to 5514.86 and permanent environmental variance estimates ranged from 0.33 to 63.27. The heritability values wereestimated between 0.03 to 0.90. The phenotypic and additive genetic correlations between body weights were positivelyestimated between 0.085 to 0.89 and 0.53 to 0.94, respectively. It was concluded that use of body weight at an earlier agewill give advantage in breeding studies for body weight at slaughter.