nfluence of sire genotype and cattle breed gene pool on sperm cryosurvival

This study characterized sires of Red-and-White, Black-and-White, and Red Steppe cattle breeds at JSC Barnaul Bull Stud Enterprise (Altai Krai, Russia) in terms of sperm production quality and resistance to freezing. A total of 50,388 ejaculates were examined before cryopreservation, including 38,333 that were frozen. The influence of individual sires was assessed on 1,716 ejaculates. Sires of the Black-and-White breed had the highest rate (31%) of sperm culling before cryopreservation. This rate was 9–18.2 percentage points higher than sires of the other two breeds (p < 0.001). The difference in frequency of ejaculates culled after thawing was significantly lower between the breeds. However, a significant difference existed between sires of the Red Steppe breed and the other two breeds (p < 0.001), with the Red Steppe breed having 1.6 and 2.0 percentage points lower culling rates. More significant differences in the frequency of ejaculates culled before cryopreservation were observed between individual sires within the Red Steppe breed than between breeds, with a maximum difference of 31.9%. A strong negative rank correlation (r = –0.90) was found between ejaculate volume and culling before freezing. There was no significant difference between the sires of Red Steppe breed in the frequency of culling ejaculates after thawing. Thus, this study demonstrates the influence of sire genotype and breed gene pool on sperm cryosurvival.