REALIZATION OF THE GENETIC POTENTIAL OF MILK PRODUCTIVITY OF BLACK-AND-WHITE CATTLE IN LARGE LIVESTOCK COMPLEXES

Abstract

When introducing selection and breeding work in dairy cattle breeding, one of the problems is the difference between the genetic potential and the actual level of livestock productivity. A study was conducted of the degree of realization of the genetic potential of daughter cows depending on the level of the bull's pedigree index in terms of milk productivity. The objects of the research were black-and-white cows (5472 heads) and Holstein breeders (38 heads). The research was carried out in seven modern and large, highly mechanized livestock complexes of Krasny Vostok Agro JSC. The cows of the breeding core were distinguished by higher milk productivity and had a slightly higher degree of realization of genetic potential. The degree of realization of the genetic potential of the mass fraction of fat and protein in milk is at a high level, and in terms of milk yield the realization of the potential is low. It has been established that with an increase in the level of RIB in bulls, there is a decrease in the degree of realization of the genetic potential, both in milk yield and in fat content. Thus, in the RIB group with a milk yield level of less than 11,500 kg, the degree of milk yield realization was 49%, and in the group with the maximum RIB (more than 16,001 kg) only 31%. With an increase in RIB for fat content in milk, the level of realization of the genetic potential of milk fat content decreases from 109% (RIB group less than 3.60%) to 97% (RIB group more than 3.91%). A similar decrease in the degree of realization of the genetic potential of milk protein production is observed when the RIB of bulls in terms of the mass fraction of protein increases from 107% (RIB less than 3.10%) to 97% (RIB more than 3.31%). Consequently, a low level of sales can be observed among producers with productivity potential that exceeds the average herd milk yield by more than 50%. Therefore, it should be taken into account that dairy cattle with a high level of genetic productivity potential do not always have a high degree of its realization.