Acrosomal damage and progressive motility of stallion semen forzen by two methods in 0.5-milliliter straws.
Post centrifugation and postthaw progressive motility and postthaw acrosomal damage were used to evaluate two different freezing methods (A and B) on 11 ejaculates of one stallion and 6 of another. In Method A, extended semen was centrifuged in 50-ml centrifugation tubes in which 0.25 ml hyperosmotic, glucose-based medium were layered in the apex of the tubes to serve as a cushion. Spermatozoa were resuspended in freezing medium, packaged in 0.5-ml PVC straws and frozen at -60 degrees C/min. Method B differed only in that the hyperosmotic cushion was omitted during centrifugation. Straws were thawed at 75 degrees C for 6 sec and then transferred into a waterbath at 37 degrees C. The postcentrifugation and postthaw progressive motility and postthaw acrosomal damage were similar for Methods A and B. Method B, however, was found to be technically easier to carry out. It also offers less chance of error or contamination because only two diluents are admixed to the semen as opposed to the three diluents used in Method A. Method B is regarded as more practical and thus preferable to Method A.
Volkmann
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DH
Department of Theriogenology, Faculty of Veterinary Science, University of Pretoria, Private Bag XO4, Onderstepoort, 0110 Republic of South Africa.