Effect of Pellet Volume on Cryopreservation of Barki Ram Semen using Cold Surfaces Made from Cattle Fat

الملخص

Preservation of semen had a major impact on sheep genetic breeding. The aim of this study was to evaluate the effect of pellet volume on semen freezability after freezing using cold surfaces made from cattle fat. A pool of three to four ejaculates were collected weekly from six rams within a period of ten weeks. Semen was diluted in egg yolk-Tris diluent and processed in 0.1, 0.2, 0.3 ml pellets. Sperm motility was evaluated after dilution, before freezing and post-thawing at 0, 1, 2 and 3-hour incubation. Viability index, acrosome integrity and leakage of intracellular enzymes of Aspartat aminotransferase (AST) and Alkaline phosphatase (AIK) were also evaluated. Spermatozoa exhibited highly significant (P>0.001) percentages of motility at 0, 1, 2 and 3 hours incubation after thawing and viability index in 0.03 ml pellet as compared to 0.2 and 0.1 ml pellets on cattle fat plate, while no significance changes between 0.2 and 0.1 ml. However there were no significant changes in the acrosome integrity and leakage of intracellular enzymes AST and AIK. In conclusion, freezing of Barki ram semen in pellet volume of 0.3 ml on surface made from cattle fat will improve the post-thawing at 0, 1, 2 and 3 hour incubation as well as Viability index.