MONITORING OF THE EAB-LOCUS OF THE ALLELE POOL OF BLOOD GROUPS IN THE SELECTION PROCESS OF HOLSTEIN CATTLE
In the results of conducted researches changes of genetic situation in the cattle herd of the agricultural enterprise SPK «Sokolovsky» in Sakhalin are determined. Control of the genetic situation of animals was realized with a help of EAB-locus of blood groups. Analysis of alleles dynamics in time from 1620 animals showed the fact of gene fund change to its improverishment. The shortening of the common number of alleles, taking place in the forming of genetypes of EAB-locus, from 45-48 (offsprings from 2004 to 2011 years of birth) to 30 (offsprings of 2018 to 2019 years of birth) happened. The offsprings of 2008-2011 and 2016-2017 years of birth had the maximum level of homozygosis - within of 10,4-12,7. Decrease of the number of effective alleles was the result of it. Use of the great number of sires, G2Y2E′2Q′ - bearers, came to increasing the birth of offsprings by 1,7 times with this allele in 2017-2018 years. The great number of seldom meeting I1O1Y2, Aʹ2Bʹ, O1QY2Eʹ3DʹGʹ, O1T2Eʹ3QʹOʹGʹʹ, Y2Aʹ2Bʹ, Y2Aʹ2BʹYʹ, B2Bʹʹ, I2Iʹ, O1Y2, QQʹ, Y2Eʹ2GʹOʹQʹ, Y2Eʹ3ОʹGʹʹ, B2Y2BʹEʹ3GʹIʹGʹʹ, G2O1Y2DʹEʹ3, G2Y2Dʹ, P2Q and others disappeared in genetypes of the herd offsprings from 2008 to 2015 years of birth. At the same time during the all period of the researches the herd increased by only 25 alleles, that came to decrease the genetic changeability in the herd. It is necessary for removal the negative processes in the herd to use such gene fund of sires, which will be able to compensate elimination of alleles in the uterine herd.