Age-related and seasonal dynamics of sperm production of Aberdeen-Angus bull sires

Methodology. The sperm production of nine Aberdeen-Angus bull sires aged 4–9 years (55–91 months) has been studied depending on the animal age, the animal color, and the season at the Head Center for Reproduction of Farm Animals, Public Corporation. Methodology and results. It is ascertained that age appears to affect the ejaculate volume, the sperm concentration in the ejaculate and the total sperm count in the ejaculate. The best values for sperm count per ejaculate were calculated for the black-color bulls at the age of 5–6 years, for the red-color bulls at the age of 7 years. Defects in native sperm comprised 78–79%. It has been revealed that the sperm parameters for the ejaculate volume ( P < 0.01), the sperm concentration and the total sperm count ( P < 0.001) tend to vary depending on the color of an animal. The values for sperm quality determined by the post-thaw sperm motility after 5 hours of incubation at 38 ° C are in the range of 8.4–9.5%. However, despite the analyzed ejaculates taken from the black-color bulls of ( n = 309) and the red-color bulls ( n = 107), it is required to carry out a survey with the higher number of qualitative ejaculates. It is necessary to find out both the cause for a high abnormal sperm count and the ways to solve the problem.