Comparsion between sire and animal model to estimate genetic (co) variances for milk yield traits

Abstract Text: Records of 847 Friesian cows  were used  to estimate genetic and phenotypic (co) variances of and between three months

                        and 305 day milk yield traits  by using sire and animal models. The Sire model, included the fixed effects of HYS, parity and

                         days open was considered  as a covariate. The random effects were sire and dam. The animal model included

                          the same fixed effects as the sire  model, whereas random effects fitted were the animal direct genetic effect and permanent

                          environmental effect.  Estimates of heritability of milk traits for sire models were moderate, ranged from 0.096 to 0.276 for single

                           trait analyses and from 0.116 to 0.264 for multiple trait analyses. In comparsion heritability estimates for milk traits from animal

                          models ranged  from 0.001 to 0.031 for single trait analyses and from 0.046 to 0.062 for multiple trait analyses. 

Keywords: Friesian Cows

                    Genetic parameter