Genetic characteristics of cows with different levels of lifetime productivity

Abstract

The results of the study of the genetic characteristics cows of the breed of Sychevka in the breeding plant KP "Rybkovskoe" of the Smolensk region with a lifetime productivity of up to 25,000 kg of milk (group I) and with a lifetime milk yield of 45,000 kg or more of milk (group II) are presented. It was found that the groups have some genetic features for EAB-alleles. The index of genetic similarity between the groups is 0.538. In the first group, 56 EAB alleles were identified, in the second – 46. The frequency of occurrence of the main alleles in the groups is 0.763 and 0.774. Among them, five marker alleles are found with a high frequency of 0.44 – 0.116. Alleles of the EAB locus b, A₁B^/, B₁G₂O₁, O₁Y₂E^/₃G^/G^//, O₂A^/₂J^/₂K^/O^/, Q^/ are more common in high-yielding cows by 2.5 – 7.2 %, and the EAB alleles B₂O₁, O^/, E^/₃G^/G^// are not found or are less common. When comparing the productivity of cows with different EAB – alleles, differences were noted. Lifetime productivity in cows with EAB alleles O₁, I₁Y₂E^/₃G^/G^//, O₂A^/₂J^/₂K^/O^/, I₂, A^/₁B^/ is higher than in cows with EAB alleles E^/₃G^/G^//, BI₁Q, Y₁A^/₁, I₁Y₂I^/. There is a significant difference in the duration of use in cows with the EAB-alleles O₁, O₁Y₂E^/₃G^/G^//, O₁I^/Q^/, I₁O₂A^/₂K^/Q^/. There were no significant differences in the content of fat and protein in milk.