DYNAMICS OF CHANGES IN THE GENETIC STRUCTURE OF THE SIMMENTAL BREED BY THE IMMUNOGENETIC CRITERIA
Labeling of populations of farm animals by individual genes and gene complexes, as well as determining on their basis the genotypic structure and the level of diversity, both structural units and populations as a whole, creates prerequisites for the development of breeding and genetic approaches aimed at preventing the narrowing of the gene pool. The immunogenetic evaluation of experimental cattle populations of Simmental breed of domestic breeding of PJSC "Red Veleten" Breeding Plant, Kharkiv region for the period from 1998 to 2018 was conducted. The studies were performed on the basis of the certification of animals according to 9 systems of blood groups (A, B, C, F, J, L, M, S, Z) with 48 monospecific reagents sera and created a data bank of data on blood types of cattle. Changes in the level of antigen saturation were detected (Аn = 0.2488 in 1998-2003, Аn = 0.2165 in 2014-2018), which indicates an overall tendency of decreasing frequencies of factors of blood groups. The EAB system of blood groups showed an increase in the value of the homozygosity coefficient from 2.12 % to 2.89 % and the degree of homozygosity (H) from 6.69 % to 7.83 % for the 20-year population study period. The data obtained is a reflection of the decrease in the overall reserve of genetic variability of the studied herd. When conducting genetic monitoring, as well as to control genetic diversity, the level of homo- and heterozygosity of cattle populations, it is recommended to use immunogenetic methods that allow the genetic level to control the genotypic situation and promptly adjust the breeding stratege.