Genetic characteristics of the herd of KP "Rybkovskoe" by alleles of the EAB-locus of blood groups

Abstract

The analysis of the genetic structure of the herd to the marker alleles of the EAB locus - blood groups was according. The EAB-allele G₂Y₂E^/₁Q^/according to the results of the study with a high frequency of 11.9 – 15.7%, in the herd, whereas its frequency is 18% for the breed was found. In the period 2011-2015 sixteen main alleles of the EAB-locus of blood groups with a total frequency of 0.802 in the herd were found. In 2016-2020, the main EAB-alleles were 12 and the frequency of their occurrence was equal 0,752. The number of four main alleles of the Red-and-White Holstein breed Y₁A^/₁, O₂A^/₂J^/₂K^/O^/, I₁Y₂E^/₃G^/G^//, B₁O₁ decreased from 0,213 to 0,102. With the highest frequency, totaling 40.6% marker EAB - alleles G₂T₂Y₂A^/₁B^/D^/G^/I^/Q^/Y^/B^// (0.052), E^/₃G^/G^// (0,070), B₁I₁Q (0,053), O₁I^/Q^/ (0,080), B₂G₂O₁Y₂D^/E^/₂G^// (0,056), b (0.095) in KP "Rybkovskoe" are found. In the breed, these alleles occur with a frequency of 29.8%. There are no significant differences between the breed and the herd in the frequency of EAB alleles. The difference did not exceed 2.4 – 2.7%. From a genetic standpoint, the animals of the herd and the breed are close. The index of genetic similarity between them is 0.95. The level of homozygosity was 6.2% in the herd in the period 2016-2020, but its increase over the past five years was 1,2%, indicating a decrease in the genetic diversity of animals. The number of producer sires used by the pedigree farm decreased to 14 and the total diversity of their alleles decreased to 15. Comparative analysis showed that the difference in productivity of the daughters of bulls with alternative EAB-alleles was from 7 to 710 kg of milk, 0.01 – 0.19% fat and 0.02 – 0.09% protein for the first lactation in favor of one or another marker allele from the producer. By the highest lactation, the differences in milk yield are 55 – 1034 kg of milk, in fat content – 0.01 – 0.22%, protein – 0.02 – 0.14%.