COMPONENTS OF VARIANCE AND COVARIANCE BETWEEN DIRECT AND FETAL EFFECTS IN PRODUCTION TRAITS

The correlation between sire of fetus effect and sire of cow effect on 3 production traits, milk yield, fat yield and protein yield, 1st lactation Holstein cows was investigated. Restricted maximum likelihood techniques were used. There was a small sire of fetus variance for milk yield, h2 = 0.23%, while the sire of fetus variances for fat and protein were small and negative. For milk yield, the genetic correlation between sire of fetus effect and sire and cow effect was -0.82. The negative sire of fetus variances for fat and protein precluded calculation of genetic correlations with sire of cow effects for fat and protein and with each other and with milk yield for sire of fetus effects.