Effect of seminal plasma concentration and various extenders on postthaw motility and glass wool-Sephadex filtration of cryopreserved stallion semen

Objective-To compare the effect of semen extender and seminal plasma on postthaw motility and filtration through a glass wool-Sephadex (GWS) filter for frozen stallion semen. Sample Population-7 stallions from which we collected ≥ 3 ejaculates/stallion. Procedures-4 experiments were conducted to evaluate postthaw quality of frozen stallion semen. Kenney extender was compared with glucose-EDTA extender by use of various dilution rates that resulted in differing concentrations of seminal plasma. Stallions known to produce semen with poor postthaw quality were used to investigate whether a particular extender or dilution rate could improve ability of such semen to survive freeze-thaw procedures. Results-Use of Kenney extender as the centrifugation extender significantly improved postthaw motility and GWS filtration, compared with glucose-EDTA. Extending semen at a dilution of 1:3 was significantly better than 1:1 for both motility and GWS filtration. In addition, including seminal plasma at a concentration of 5% in the cryopreserved semen resulted in significantly higher yield of spermatozoa after GWS filtration, compared with complete removal of SP or use of seminal plasma at 25%. Lastly, semen with poor postthaw quality had significantly improved postthaw quality in regard to motility and GWS filtration when semen was frozen with seminal plasma at a concentration of 5%, compared with semen frozen with seminal plasma at a concentration of 25%. Conclusions and Clinical Relevance-Use of Kenney extender at a high dilution (≥ 1:3) immediately after collection of semen can improve postthaw quality of frozen stallion semen.