Effect of Cryopreservation Protocol on Post-thaw Characteristics of Stallion Spermatozoa

Effect of Cryopreservation Protocol on Post-Thaw Characteristics of Stallion Spermatozoa. (August 2009) Jose L. Salazar, B.S., Texas A&M University Chair of Advisory Committee: Dr. Dickson D. Varner Three ejaculates from each of eight stallions were initially centrifuged in INRA 96 extender and spermatozoal pellets were resuspended in a milk/egg yolk-based freezing extender or an egg yolk-based freezing extender. Extended semen was exposed to a fast pre-freeze cooling rate (FAST semen immediately subjected to cryopreservation) or a slow pre-freeze cooling rate (SLOW semen pre-cooled at a controlled rate for 80 minutes prior to cryopreservation). After thawing, semen was diluted in initial freezing medium (FM) or INRA 96 prior to analysis of 9 experimental endpoints: total motility (MOT; %), progressive motility (PMOT; %), curvilinear velocity (VCL; μm/sec), average-path velocity (VAP; μm/sec), straight-line velocity (VSL; μm/sec), linearity (LIN; %), intact acrosomal and plasma membranes (AIVIAB; %), intact acrosomal membranes (AI; %), and intact plasma membranes (VIAB; %). Eight of nine experimental endpoints (MOT, PMOT, VAP, VSL, LIN AIVIAB, AI, and VIAB) were affected by extender type, with LE extender yielding higher values than MF extender for these variables (P<0.05). Exposure of extended semen to a slow pre-freeze cooling period resulted in increased values for seven of nine endpoints, as compared to a