Genetic and biochemical characteristics of sire bulls (Bos taurus) in reproductive biotechnologies

Abstract

This study aims to investigate the relationship between polymorphic serum protein systems – transferrin (Tf), amylase (Am), and ceruloplasmin, (Cp)- and sperm production parameters, as well as fertilization rates, in Red Steppe and Angeln cattle. Electrophoresis was employed to determine protein phenotypes and calculate levels of heterozygosity. The relevance of this study is justified by the necessity of establishing immunogenetic markers to enhance selection efficiency. Analysis revealed breed-specific immunogenetic markers. Regarding the Transferrin (Tf) locus in Red Steppe bulls, the highest sperm production indicators were observed in homozygous individuals (TfAA, TfDD), whereas in the Angeln breed, superior sperm volume was noted in heterozygous individuals (TfAD). Cows inseminated with sperm from heterozygous pairs generally exhibited significantly higher fertility rates than those inseminated with sperm from homozygous pairs. The Amylase (Am) system confirmed the negative influence of the AmCC phenotype, which is associated with the lowest level of sperm production and fertility. In the Red Steppe breed, homozygous AmBB sire bulls possessed the highest reproductive qualities. The study of the Ceruloplasmin (Cp) system revealed that in the Red Steppe breed, heterozygotes (CpBC) demonstrated the highest fertility, despite the superior sperm productivity of homozygotes (CpAA). Conversely, in the Angeln breed, CpBB homozygotes prevailed in both indicators. These results suggest that the optimal level of heterozygosity may depend on breed-specific genetic backgrounds. Red steppe bulls that were homozygous or possessed a 25% heterozygosity level exhibited the highest sperm production and fertilization ability, whereas the optimal level of Angeln bulls was 50%. It is recommended that homozygosity levels of Tf, Am, and Cp be incorporated into selection indices when purchasing sire bulls to improve the reproductive qualities of the herd.