Temperature-processing effect on equine semen cryopreservation

Advances in semen cryopreservation, alongside the implementation of new laboratory techniques to better protect sperm cells viability, have allowed increased quality and fertility of frozen semen in mammals. However, this process can impair the acrosomal integrity, viability, and motility of spermatozoa to some degree. Deleterious effects of cryopreservation are largely due to shock temperature during the freezing process that causes osmotic and oxidative stress. The aim of the study was to assess whether an early semen cooling could influence main parameters of equine frozen-thawed semen. Eight healthy and fertile Sicilian Oriental Purebred stallions underwent semen collection by using a Missouri artificial vagina. Semen samples were processed according to two different freezing protocols. Semen was extended 1:1 ratio (semen:extender) in INRA-96 extender prewarmed at 37°C; thereafter in protocol A diluted samples were placed into conical tubes with 2ml Maxifreeze cushion and centrifuged at room temperature for 10 min at 600g. After removal of supernatant and cushion, the sperm pellet was resuspended with INRA-freeze to a final concentration of <200 × 106 spermatozoa/ml. ...