INTERBREED CROSSING IN THE ASPECT OF CREATION AND IMPROVEMENT IN CATTLE

The purpose of the research was to study the influence of the conditional share of Holstein heredity on the indicators of milk productivity of Ukrainian Black-and-White and Red-and-White dairy cows in identical conditions of the same farm. The following cross-breed genotypes of animals with different share of Holstein heredity were evaluated: I – < 49.9–50.0; II – 50.1–62.5; III – 62.6–75.0; IV – 75.1–87.5; V – 87.6–93.75 and VI – > 93.76%. A significant influence of the conditional share of heredity for the Holstein breed on the characteristics of milk productivity of cows within the assessment indicators of the first, third and higher lactations has been established. A linear correlation between the conditional Holstein heredity and milk productivity of crossbreed cows of the Ukrainian Black-and-White dairy breed was established. With the increase in the conditional proportion of Holstein blood, the milk yield and milk fat of crossbred cows increased within all lactations considered. In cows of the Ukrainian Red-and-White dairy breed, this relationship turned out to be curvilinear – with an increase in Holstein blood to 75.0%, a decline in milk productivity was observed, and above 75.1% – milk yield and milk fat indicators increased.