Growth and meat productivity of bulls depending on the similarity of their blood group B antigens with mothers

Various molecular genetic markers are used to comprehensively assess the breeding value of animals based on genetic information. Therefore, an important place in the qualitative improvement of beef cattle breeds is occupied by the improvement of methods of animal selection using the immunogenetic characteristics of their blood. The purpose of the study is to determine the dependence of weight growth and meat productivity of animals of the Ukrainian beef breed on the number of similar antigenic factors of the B blood group system in them and their mothers. After weaning, the first group contained bulls (n = 12) who had similar antigens from 2 to 6 inclusive. The second group (n = 15) – from 7 to 13. When studying the features of weight gain and meat productivity of bulls, it was proved that the similarity in the B system of cattle blood groups between mother and offspring is informative regarding the homo- or heterozygosity of the latter. It was found that animals with a lower amount of antigens similar to the mother outperformed (by 9.3%) homozygous peers in the test from 8 to 18 months of age in terms of average daily weight gain and had a higher live weight (by 8.0%) at 18 months, indicating their better early maturity. With lower antigenic similarity between mother and offspring, the expression of meat forms is 7.8% and 6.0% higher, respectively, at 15 and 18 months of age.After slaughter, there is no significant difference between homozygous and heterozygous bulls in terms of meat productivity, including pre-slaughter live and slaughter weight. When selecting offsprings with fewer antigens similar to their mother, they tend to reduce the slaughter yield (by 0.5 points) and the muscle content in carcasses (by 3.2%). The selection of bulls of Ukrainian beef breed with a smaller number of antigens of the B blood group system, similar to mothers, will help to improve their weight growth and the expression of meat forms, and will allow predicting future meat productivity