Influence of polymorphism of complex of csn3 and lgb genes on the dairy productivity in holstein cattle

Abstract

The study presents the results obtained in the course of DNA testing of allelic polymorphism by PCR-RFLP on CSN3 and LGB genes and the associations of their complex genotypes to the indicators of milk productivity of Holstein cow-heifers.Genetic polymorphism was detected by digestion with the endonucleases Hinf I (CSN3) and Hae III (LGB). All integrated CSN3/LGB genotypes were identified during the work. The maximum frequency of occurrence is observed in a combination of heterozygous AB/AB genotypes – 120 animals (25.5%), which is the fourth part of the studied cattle population. The group of animals with homozygous BB/BB genotypes of CSN3/LGB genes is the smallest one – 10 animals (2.1%). Milk productivity test, based on the complex CSN3 and LGB genotypes is observed in heifers with an integrated combination of CSN3BBLGBAAshowed that a significantly high level of productivity for 305 days of lactation – 7239.8 kg, and a minimum level of productivity (6222.9 kg) is observed in heifers with the complex CSN3BBLGBAB genotype, compared with indicators of milk yield of cow-heifers with other integrated genotypes. According to the content of the mass fraction of fat, the best indicators were established in the subpopulation of animals with the complex AA/AB genotype – 3.90%, and the worst result was recorded in the group of animals with the complex AB/AA genotype, which amounted to 3.44%. The high content of the mass fraction of protein was observed in individuals by the complexof the CSN3 and LGB genes BB/AA – 3.43%, and a reduced level of protein was observed in heifers with a combination of homozygous AA/AA and BB/BB genotypes by the genes under study – 3.18%. Thus, individuals carrying the homozygous A allele of the kappa-casein (CSN3) gene and the homozygous B allele of the beta-lactoglobulin (LGB) gene in the integrated genotype favorably differed on the main indicators of milk productivity.