INFLUENCE OF GENETIC FACTOR ON PRODUCTIVE LONGEVITY OF HOLSTEIN COWS

The dynamics of changes in the fat and protein content in cow milk in different seasons of the year showed the presence of a certain amplitude fluctuations between groups. The highest fat content of 3.65% was observed in the summer in cows of the Reflection Sovereign line, which is 0.04% higher than the analogs of the Vis Beck Ideal line. The highest value of the protein mass fraction of 3.28-3.29% was observed in the autumn period, the differences in protein content in the studied groups were insignificant. The best indicators are autumn milk in cows of the Reflection Sovereign line (increased fat content - 3.65%, protein - 3.27% and lactose - 4.61%). Seasonal variations in lactose levels are weaker than fat and protein. The highest content of dry matter in milk during the year was observed in the autumn (12.57%), the lowest (12.21%) — in the spring. After analyzing the data, we see that seasonal conditions have different effects on the content of individual components of milk cows Holstein herd. For the most complete realization of the genetic potential of productive longevity and milk productivity of cows use cows belonging to the line Reflection Sovereign.