Genetic monitoring cattle a herd of the sychev breed

According to the results of immunogenetic studies (2006-2020), the dynamics of changes in the herd allelofond according to genetic markers of blood groups with a period of five years was studied in JSC Smolenskoye for breeding work. A reduction in the number of EAB alleles in breeding bulls from 29 to 16, in cows from 39 to 33 was revealed. The frequency of occurrence of 12-13 main EAB alleles in the herd is 0.737 - 0.753, in the breed - 0,778. During all monitoring periods, the EAB alleles - G2Y2E/1Q/, Y1A/1, E/3G/G//, Q/ were found with a frequency of 4% and higher. There was an increase in the level of homozygosity for dam stock by 1.1%, for producing bulls - by more than 3%. It was found that in the herd for 2020 with a total frequency of 0.318, there are alleles of the EAB locus B2±G2O1Y2D/E/2G//, E/3G/, E/3G/G//, G2T2Y2A/1B/G/I/Q/Y/B//, G1A/1. The frequency of their occurrence by breed is 0.120. In 13% of cows of the herd, there are EAB alleles A1B/, B1I1Q, O1I/Q/, G3O1T1A/2E/3F/2K/G//, I1Y2I/, in the breed they occur in 22.3% of animals. It was revealed that alleles of the Holstein breed in different periods were found, respectively, in 43.3, 25.9, 61.7 percent of cows, alleles of the breed of Sychevka - in 19.2, 36.0, 23.2%. The index of genetic similarity between the breeding farms of the breed of Sychevka varied from 0.632-0.884, between the animals of the herd and the breed it was 0.750-0.855. We note that in bulls evaluated by the quality of offspring, the difference in the productivity of daughters in favor of one or another preferential allele from the producer was 61-1403 kg of milk, 0,01-0,15% fat and up to 0.06 percent protein for the first lactation. According to the highest lactation, the differences in milk yield are 26-1083 kg of milk, in fat content - 0,02-0,19%, protein 0,01-0,06%.

EAB-alleles, genetic monitoring, frequency of occurrence, blood groups, selection, homozygosity, productivity