ALLELES OF BLOOD GROUPS WITH HIGH AND LOW CONCENTRATION BY THE COWS OF BLACK-AND-WHITE BREED IN THE OREL REGION
The study of blood groups, the concentration of alleles of blood groups and the dynamics of the frequency of occurrence of alleles are of great importance in the selection of dairy cattle. This is due to the need to study the genetic diversity of breeds and, in particular, immunogenetic polymorphism. In this regard, the alleles of blood groups with a high and rare concentration in the population of Black-and-White cattle of the Orel region are studied in the work. The livestock of cows in 6 herds were investigated: (farms Streletskoe, Michurin, Agrofirm Mtsenskaya, Slavyanskoe, Kurakinskoe, Krasnaya Zvezda, n = 306). As a result of the research in all herds of the Orel region, it was established that from 33.3% of all the animals are carriers of the G<sub>2</sub>, H′, F, C<sub>1</sub> antigens. Their concentration ranged from 33.33 to 65.54%, from 44.44 to 89.23, from 64.15 to 93.88 and from 56.60 to 63.08%, respectively. So, in farm Streletskoe there was a high concentration in system B: G<sub>2</sub> - 63.54%; Y<sub>2</sub> - 63.54%; Q′ - 63.54%; in system S: H′ - 69.79; in system C: X<sub>2</sub> - 64.58%; in the F-V system: FF - 84.38%. Low concentration of alleles was typical for system B for Q<sub>4</sub> - 1.04%; F′<sub>3 </sub>- 1.04%; in system S: U′ - 1.04%; in system C: X<sub>4</sub> - 1.04%; in the F-V system: R′′ - 1.04%. In the studied herds, certain alleles are revealed, which can be genetic markers of the milk productivity of cows. In the future, it is proposed to conduct more detailed immunogenetic monitoring in the Orel cattle population.