Effect of blood groups in Holstein cattle breeding for producing ability

Abstract

The research goal was to study the connection of antigens, alleles of EAB-locus and genotypes of EAF-locus of blood groups with milk producing ability of local Holstein cows and the cows imported from Australia to the agricultural enterprise “Zarya” of the Khabarovsk Region. The studies were conducted according to generally accepted methodology. The research was based on the archival data of animal performance records. The selected animals formed three groups: Group 1 - local cattle bred in the agricultural enterprise “Zarya”, born in 2004 and 2005; Group 2 - the cattle imported to the enterprise “Zarya” from Australia in 1986 and 1987; Group 3 - the cattle imported from Australia to the enterprise in 2006 and 2007. It was found that the cows of this enterprise with lower milk producing ability indices were the carriers of antigens G’, G’’ (EAB-locus), U’ (EAS-locus) and EAB-allele E’₃G’G’’ in all studied groups; the difference in the groups was from 32.4 kg to 295.5 kg of milk as compared to the average milk yield indices. The cows in all groups that inherited the antigens L (EAL-locus) and Z (EAZ-locus) differed by higher milk producing ability; the difference in average indices achieved 225.7 kg. The cows from locally bred group that were the carriers of EAB-alleles O₂A’₂J’₂K’O’ exceeded by milk yield the average indices in the group by 759.1 kg, p < 0.05. The imported cows carrying the alleles O₂A’₂J’₂K’O’ and E’₃D’G’O’ showed lower milk producing ability, and the carriers of G₂I₁ allele exceeded the average indices by 173.8-733.4 kg, p < 0.05. The reliable differences in milk producing ability were revealed between the animals carrying homozygous and heterozygous genotypes regarding EAF-locus. The heterozygous cows surpassed the homozygous cows by 542.9 kg of milk, p < 0.01, in the locally bred group; and by 377.9 kg, p < 0.001, in the group of cows imported in 2006 and 2007. The milk producing ability of animals imported in 2006 and 2007 years that inherited F/V genotype and antigens I₁ and I₂ was significantly higher; it was higher by 810.2-852.4 kg than the average milk producing ability in the group, p < 0.01.