Motility and fertilizing ability of frozen-thawed ramspermfromtwo sheep breeds
2011
Kubovičová, E., Animal Production Research Centre, Nitra (Slovak Republic) | Makarevich, A.V., Animal Production Research Centre, Nitra (Slovak Republic) | Špaleková, E., Slovak Univ. of Agriculture in Nitra (Slovak Republic) | Hegedušová, Z., Research Institute for Cattle Breeding, Ltd., Rapotín (Czech Republic)
The aim of the study was to evaluate motility parameters of Lacaune (Lc) and East-Friesian (EF) ram frozen-thawed spermatozoa by CASA (Computer-Automated Sperm Analysis) technique in relation to their in vivo fertilizing ability. Fresh ejaculates were diluted in a Triladyl extender containing 20 % egg yolk, 6 % glycerol and 0.1 % trehalose and frozen in a liquid nitrogen vapour. The evaluation of frozen-thawed semen showed significant differences in sperm motility between the two sheep breeds by 30 (P less than 0.001) to 120 (P less than 0.05) min post thawing. Whole motility of spermatozoa was significantly reduced during incubation and by 120 min it was dropped to 7.68 (Lc) and 13.36 (EF) %. Similarly, the percentage of progressive motile spermatozoa was significantly reduced (P less than 0.001) during incubation, and only 6.31 % of Lc and 11.81 % of EF ram spermatozoa were progressive motile by 120 min of incubation. Significant decline of the velocity characteristics, such as a path velocity (VAP), curveilance velocity (VCL) and progressive velocity (VSL) was observed by 30 min (P less than 0.001) and 120 min (P less than 0.05) post thawing in Lc compared to the EF ram semen. Ram frozen-thawed semen was used for insemination of 99 hormonally synchronized ewes. The differences detected in the motility parameters of frozen-thawed spermatozoa from two sheep breeds were reflected in the pregnancy (12.24 and 28.00 %) and lambing rate (0.0 and 56.00 %) for EF and Lc, respectively. In conclusion, cryopreservation significantly affects the quality of frozen-thawed sperm by lowering sperm motion characteristics. This study revealed differences in basal motility parameters between ram sperm of two sheep breeds.
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