Cryopreservation of white-tail deer epididymal sperm for artificial insemination

The ability to cryopreserve epididymal sperm from mature postmortem bucks has long been of interest to both wildlife conservationists and deer ranchers. Increased understanding of the cryobiology of epididymal sperm from a non domestic species, such as White-tail deer, could aid in development of future protocols to assist in the preservation of endangered species. In Experiment I, results showed that after cooling postmortem bull testes for 22 hours, no significant difference was noted between sperm parameters of epididymal sperm collected at room temperature or at a cool enviorment. In Experiment II, it was shown that White-tail deer sperm could be successfully cryopreserved using a bovine freezing protocol. Also, if immediate processing of epididymal sperm is not an option, testes can be held within the scrotum at 10°C to 15°C for up to 24 hours prior to processing the sperm for freezing. In Experiment III, post-thaw normal sperm morphology results show that glycerol should be considered over DMSO when freezing White-tail deer epididymal sperm. In Experiment IV, it was shown that White-tail deer epididymal sperm can be held in the presence of glycerol for up to 12 hours and still result in post-thaw motility values \u3e30%. Also, when comparing exposure time of White-tail deer epididymal sperm to glycerol there was relatively no change in post-thaw membrane integrity from 0 hours to 24 hours. In the final experiment, the fawning rates of three different estrous synchronization protocols using timed artificial insemination were compared over two consecutive breeding seasons. The most preferred synchronization protocol was a 14 day CIDR with an eCG injection at the time of CIDR removal. A preliminary experiment was then conducted using the 14 day CIDR with eCG to synchronize and artificially inseminate six does with frozen-thawed epididymal sperm, resulting in five healthy fawns from three pregnancies