d irected formation of dairy cows of the south of ukraine with help of polymorphism of structural genes .
A comparative analysis of the DNA polymorphism of structural genes has been carried out and their effect on the signs of milk productivity has been evaluated depending on the intensity of the formation of the organism and linear distribution of cows. The study was carried out in the conditions of cattle herds of Ukrainian black -motley and red dairy, red steppe breeds. Within each of them, two groups of animals were formed - with a moderate and fast type of intensity of formation of the organism. A comparative analysis of the genetic structure of these rocks and lines with polymorphism of the CSN3, BLG, GH and LEP genes using the PCR-RFLP method, as well as an analysis of their milk productivity, was performed.The results obtained did not establish an unambiguous dependence of the productive indices of cows on their pedigree in the examined loci. But it should be noted on the CSN3 gene that the AB genotypes of most research groups, which had higher milk yields during ontogenesis, and CC and TT homozygotes for LEP. Representatives of the rapid intensity of body formation, regardless of homo - or heterozygosity, are marked by high productive indicators, excluding the leptin locus, where representatives of the slow growth rate predominantly prevailed. The data obtained indicate that alleles of the CNS3 locus were included in the intergroup differentiation of the considered livestock lines, but without radically different characteristics. The livestock of the Hannover RED and Starbuck lines behind the BLG locus had a close percentage of heterozygotes (50,0 and 52,4 %, respectively), however, in the Valiant and Starbuck experimental groups, the BLG B allele frequency revealed close values of 0,577 and 0,500. Studies have established that, indeed, the Ukrainian black -motley dairy breed, as a daughter to the Holstein breed, has the highest occurrence of the GH V allele, especially among the Elevation, Annas Adema, Hannover RED and Starbuck lines.