Techniques for canine semen freezing need to be optimized in order to maximize pregnancy rates and to increase the number of AI-doses obtainable from a single ejaculate. To improve these techniques, simultaneous investigation of different aspects of the cryopreservation process must be performed, to find the best combination of extender and freezing and thawing rate. Four ejaculates were obtained from each of five dogs, and split-samples were diluted in a Tris citrate glucose extender containing 0.5% Equex STM Paste and either 3 or 5% glycerol. Two ejaculates from each dog were frozen at a slow freezing rate (10 degrees C/min in the range -6 degrees to -40 degrees C) and two at a fast freezing rate (50 degrees C/min in the range -6 degrees to -40 degrees C), in 0.5 mi straws using a programmable freezer. Prior to evaluation, the straws from each freezing rate and glycerol concentration were thawed in a water-bath, either at 38 degrees C for 1 min or at 70 degrees C for 8 s. Samples of cryopreserved semen were evaluated for motility and for the proportion of spermatozoa having an intact plasma membrane, immediately after thawing and during 5 h of incubation at 38 degrees C. The higher glycerol concentration and the faster thawing rate tested favoured the recovery of living and motile spermatozoa and their survival during incubation, while the tested freezing rates had no influence on sperm post-thaw longevity.
Cryosurvival of dog spermatozoa at different glycerol concentrations and freezing/thawing rates
ROTA, ALESSANDRA;VANNOZZI, IACOPO;
1998-01-01
Abstract
Techniques for canine semen freezing need to be optimized in order to maximize pregnancy rates and to increase the number of AI-doses obtainable from a single ejaculate. To improve these techniques, simultaneous investigation of different aspects of the cryopreservation process must be performed, to find the best combination of extender and freezing and thawing rate. Four ejaculates were obtained from each of five dogs, and split-samples were diluted in a Tris citrate glucose extender containing 0.5% Equex STM Paste and either 3 or 5% glycerol. Two ejaculates from each dog were frozen at a slow freezing rate (10 degrees C/min in the range -6 degrees to -40 degrees C) and two at a fast freezing rate (50 degrees C/min in the range -6 degrees to -40 degrees C), in 0.5 mi straws using a programmable freezer. Prior to evaluation, the straws from each freezing rate and glycerol concentration were thawed in a water-bath, either at 38 degrees C for 1 min or at 70 degrees C for 8 s. Samples of cryopreserved semen were evaluated for motility and for the proportion of spermatozoa having an intact plasma membrane, immediately after thawing and during 5 h of incubation at 38 degrees C. The higher glycerol concentration and the faster thawing rate tested favoured the recovery of living and motile spermatozoa and their survival during incubation, while the tested freezing rates had no influence on sperm post-thaw longevity.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
