Polymorphism of the thyroglobulin gene and its interrelationship with milk productivity indicators in first-calf Holstein cows

In recent years, dairy cattle breeding have been actively developing, especially in relation to Holstein cows. In this regard, there is a need to improve their milk productivity, especially milk yield and fat content. To achieve this goal, breeders use genotyping to determine the genetic potential of animals and identify first-calf cows with desirable alleles for use in breeding. In this study, the PCR-RFLP method was used to amplify the DNA of first-calf cows, followed by analysis of the amplification products using horizontal electrophoresis. The results of the study allowed us to assess the genetic potential of the Holstein breed and individual animals in terms of milk productivity. Analysis of polymorphism in the TG5 gene showed that cows with the TG5TT genotype have the highest milk fat content and higher milk yield. These results have practical application in cattle breeding, as they can be used for control and adjustment of breeding processes. The conclusions of the study indicate the need to use animals that are carriers of the desirable T allele in the TG5 gene when selecting parent pairs for breeding in order to improve milk productivity and fat content.