title: Impact of using a fast-freezing technique and different thawing protocols on viability and fertility of frozen equine spermatozoa.
abstract: The effects of freezing technique and thawing protocol on thawed semen viability and fertility were studied. Ejaculates from 5 stallions (n = 25) were frozen by conventional or a fast-freezing technique. Frozen semen was thawed by two thawing protocols (37 °C 30 s(-1) or 75 °C 7 s(-1) ). Thawed semen was evaluated by progressive motility, vigour, morphology and plasma membrane integrity. Mares (n = 25) were inseminated with 300 (n = 11) or 150 (n = 14) million spermatozoa. A greater (P < 0.05) vigour and progressively motile spermatozoa were detected, respectively, at thawing and after 20 min post-thawing in the fast-freezing technique than in the conventional one. Plasma membrane integrity was also greater (P < 0.05) in semen frozen with the fast-freezing technique. Semen viability was not affected by thawing protocol. Pregnancy rate using the fast-freezing technique was 76% (19/25), and did not differ (P > 0.05) between insemination doses. We concluded that the 150 million progressively motile spermatozoa per dose using a deep-horn insemination maximises the use of equine semen. The fast-freezing technique, as compared to the conventional one, efficiently preserves the viability and fertilising capacity of spermatozoa, indicating a new method to improve the fertility of frozen equine semen.
authors: Department of Animal Reproduction, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, Pirassununga, SP, Brazil.
authors: G
authors: G
authors: Pugliesi
authors: R
authors: R
authors: Fürst
authors: G R
authors: GR
authors: Carvalho
mesh_terms: D000818:Animals; D002470:Cell Survival; D015925:Cryopreservation / Q000295:instrumentation / Q000379:methods / Q000662:veterinary*; D005260:Female; D005298:Fertility; D006736:Horses; D007315:Insemination, Artificial / Q000379:methods / Q000662:veterinary*; D008297:Male; D011247:Pregnancy; D012661:Semen / Q000166:cytology; D012662:Semen Preservation / Q000295:instrumentation / Q000379:methods / Q000662:veterinary*
keywords: Artificial insemination; cryopreservation; semen extender; stallion