Selection and genetic parameters of productive traits and exterior features of black-and-white cattle in Western Siberia

The article presents materials on the selection and genetic indicators of black-and-white cattle. The amount of repeatability allows for selection by productive qualities already in the first lactation. There was a significant negative moderate relationship between the mass fraction of fat and milk yield for 305 days of lactation (- 0.308; Р>0,999). There is a tendency of negative weak dependence between the milk yield and the mass fraction of protein, namely, the increase in milk yield is accompanied by a slight decrease in protein content. A weak positive relationship was established between the mass fraction of protein and the mass fraction of fat in milk yield for 305 days of lactation (0.255; P>0.999). It follows that unilateral selection by the mass fraction of protein can increase the fat content. The heritability coefficient of milk yield was 0.266, fat mass fraction - 0.403, protein mass fraction - 0.082. Exterior features of livestock have been established.