The impact of improving breed on dairy productivity of cows of different breeds of domestic selection

Breeding of cattle of dairy productivity in Ukraine in recent years is carried out with the intensive use of reproductive breeding, where the parent breed is Holstein, which leads to the appearance in the herd or breed of individuals with a huge diversity of genotypes with heterogeneous productivity. For the consolidation of cattle of Ukrainian dairy breeds for economically useful features, it is necessary to set the maximum permissible limits of the conditional stiffness of the Holstein breed in the genotype of animals of newly created breeds. The purpose of the research was to determine the milk productivity of cows of different breeds of breeding herds of the experimental farms of the NAAS, depending on the conditional share of blood in their genotype of the Holstein breed. The studies were conducted in herds of research farms of the NAAS according to the data of breeding records of cows of Ukrainian Black-and-White Dairy (2130 heads), Ukrainian Red-and-White Dairy breeds (689 heads) and Ukrainian Red Dairy (176 heads). Significant differentiation of milk yields of cows of different breeds has been established depending on the proportion of conditioned blood supply by the Holstein breed. The possibility of even increase of milk productivity of cows of Ukrainian Red Dairy of the first and higher lactation with increase of a share of blood count on Holstein breed is proved. For cows of the Ukrainian Red-and-White dairy breed, the upper limit of conditional blood yield for the Holstein breed, which contributed to the increase in milk yield of the first lactation was 87.49 %, and for the higher lactation – 75.0 %. Animals of the Ukrainian Black-and-White Dairy breed have a higher hope of first and higher lactation with an increase in their genotype of the conditional share of blood by the breed of improvement to 75.0 %. An increase in the proportion of conditional blood over Holstein breeds beyond the specified limits leads to a decrease in dairy productivity of cows. In general, the further breeding of cattle of Ukrainian dairy breeds requires a clear justification for the use of Holstein breed for reproductive breeding, taking into account the results of the effect of conditional blood on the milk productivity of cows.