Preserving of the bovine chilled semen viability

The aim of the work is to assess the biological usefulness of bull semen when cooled to 5 °C and stored for a period of time. Sperm cooling is less traumatic for cells than deep freezing. The fertilizing capacity of chilled sperm is higher than cryopreserved sperm, but it persists for several days, which limits its use. The study was conducted using native sperm from black-and-white (n = 6) and Ayrshire bulls (n = 3). Two diluents were used in the experiment: OptiXcell commercial diluent (IMV) (France) was used as a control, and an experimental diluent based on Tris was developed as an experiment. There was no significant difference in overall and progressive mobility between the studied diluents. In most cases, the spermatozoa were alive for 10 days. If we take into account the progressive mobility of 40% as the minimum permissible for artificial insemination, on average, the studied bulls had it during storage for 120 hours. At the same time, there were individual ejaculates that had progressive mobility (40% and higher) even after 168 hours of storage. There were no significant differences in membrane safety when diluted with the studied diluents. When stored for 72 hours, there was practically no decrease in the number of intact cells when using an experimental diluent. The preparation and application of an experimental diluent are economically more profitable than using a Western analogue — OptiXcell (IMV). At the same time, the diluent developed by the authors is not inferior in characteristics (qualitative indicators of spermatozoa), and even surpasses the foreign one.