A comparison between freezing methods for the cryopreservation of stallion spermatozoa.
The effects of sperm freezing concentration (40 x 10(6)mL(-1) vs. 400 x 10(6)mL(-1)), straw size (0.25 mL vs. 0.5 mL) and freezing method (liquid nitrogen vapour in a Styrofoam box vs. programmable freezing machine) were evaluated in a 2 x 2 x 2 factorial experimental design using 3 split ejaculates from each of 4 stallions. Immediately after thawing, the total motility and forward progressive motility of spermatozoa frozen at a concentration of 40 x 10(6)mL(-1) was higher than for spermatozoa frozen at 400 x 10(6)mL(-1). No significant differences were observed in the semen parameters assessed after cryopreservation in either 0.25 or 0.5 mL straws. However, the programmable freezer provided a more consistent and reliable freezing rate than liquid nitrogen vapour. We conclude that an effective protocol for the cryopreservation of stallion spermatozoa at low concentrations would include concentrations of 40 x 10(6)mL(-1) in 0.25 mL straws using a programmable freezer. This freezing protocol would be suitable for emerging sperm technologies such as sex-preselection of stallion spermatozoa as the sorting process yields only low numbers of spermatozoa in a small volume available for either immediate insemination or cryopreservation.
Clulow
J R
JR
Centre for Advanced Technologies in Animal Genetics and Reproduction, Faculty of Veterinary Science, University of Sydney, Sydney, NSW 2006, Australia. jenclulow@hotmail.com
Mansfield
L J
LJ
Morris
L H A
LH
Evans
G
G
Maxwell
W M C
WM
D000177:Acrosome / Q000502:physiology; D000818:Animals; D015925:Cryopreservation / Q000379:methods / Q000662:veterinary*; D003451:Cryoprotective Agents / Q000494:pharmacology*; D006736:Horses / Q000502:physiology*; D016014:Linear Models; D008297:Male; D008856:Microscopy, Fluorescence; D008858:Microscopy, Phase-Contrast / Q000662:veterinary; D011897:Random Allocation; D012662:Semen Preservation / Q000379:methods / Q000662:veterinary*; D013081:Sperm Motility / Q000502:physiology; D013094:Spermatozoa / Q000502:physiology* / Q000648:ultrastructure
D003451:Cryoprotective Agents