Cryopreservation of epididymal dog sperm

A method of cryopreservation was developed for sperm salvaged from the caud a epididymis and vas deferens of domestic dog testes. Four modifications of the glycerol concentration of a buffer used for cryopreservation of dog ej aculates and two freezing rates were assessed for their effect upon post-th aw spermatozoal motility and morphology. There was no statistical differenc e between the four glycerol concentrations or the two freezing rates and th e buffer containing 6% glycerol and the freezing rate provided by 0.5 ml st raws was chosen for further study. This method resulted in a significant re duction in the percentage of live spermatozoa detected with Hoechst stainin g and a reduction in the percentage of capacitated spermatozoa after freeze -thawing. How ever, there was no difference in the ability of frozen-thawed spermatozoa to penetrate homologous oocytes. This study demonstrates that cryopreservation of epididymal canine sperm ca n be performed using methods similar to those established for ejaculates of the same species, and that despite some damage, spermatozoa retain their F unctional ability. (C) 2001 Elsevier Science B.V. All rights reserved.