The influence of external irradiation and cryopreservation on sperm quality of stud bulls

The purpose of the study is to investigate combined effect of external radiation exposure and cryopreservation on the semen quality of fertile bulls. The study presents results of research on clinical and physiological state of stud bulls exposed to sublethal doses of external radiation and effect of cryopreservation on the semen quality. The bulls divided in 4 groups, the animals of each group were exposed to the single radiation dose of 1, 2, 3, and 4 Gy. Blood was tested in 3, 7, 15, 30, 45, 60 days after exposure. Sperm was taken every week, after testing its quality the sperm was frozen and kept in liquid nitrogen. On the 7th day after the exposure of 3 Gy and 4 Gy the concentration of white blood cells decreased by 44% and 55% respectively, as compared to the initial level. Authors present dynamic data on dead sperm cells level in the cryopreserved and thawed sperm in relation to a radiation dose received by the bulls. They demonstrate the dependence of the semen quality on dose. As compared with the control points, concentration of sperm decreased by 40-75% in 8 weeks after the exposure of the bulls to doses of 1-4 Gy, there was a significant decline in motility and viability. Sperm motility recovered in 38-40 weeks after exposure to radiation.