Effect of storage and single layer centrifugation before cryopreservation on stallion sperm cryosurvival.
Authors: Nunes M M, Morrell J M, Santos F C C, Miragaya M H, Gallelli M F, Rodriguez M, Guimarães J D
Journal: Journal of equine veterinary science
Summary
# Editorial Summary Cryopreservation of stallion semen remains challenging, with individual males showing marked variation in post-thaw sperm survival. This investigation examined whether brief cooled storage prior to freezing, combined with different centrifugation approaches, could optimise progressive motility recovery in thawed samples across "good freezer" and "bad freezer" stallions. Researchers processed ejaculates using standard centrifugation or single-layer centrifugation (SLC), either immediately or following 8-hour storage at 5°C or 15°C, then assessed progressive motility before centrifugation, after processing, and post-thaw. Single-layer centrifugation consistently yielded superior post-thaw motility compared to standard centrifugation across all storage conditions (p ≤ 0.05), whilst immediate freezing without storage produced the highest initial motility at 72% versus 53% for stored samples. Critically, "bad freezer" stallions exhibited post-thaw motility below 30% when samples had undergone storage, regardless of method. For practitioners, these findings suggest that good freezers tolerate 8-hour storage at either temperature before SLC processing without significant quality loss, potentially improving workflow flexibility; however, bad freezer semen should be processed immediately post-collection using SLC to maximise viable sperm recovery, warranting pre-screening protocols to identify individual stallion freezability before implementing storage protocols.
Read the full abstract on PubMed
Practical Takeaways
- •Use Single Layer Centrifugation instead of standard centrifugation when preparing stallion semen for freezing to improve post-thaw survival rates
- •Assess individual stallion freezability before planning storage protocols; poor freezers require immediate processing by SLC rather than delayed storage
- •Good freezer stallions can be stored for 8 hours at either 5°C or 15°C before freezing without substantial motility loss, allowing flexible collection and processing schedules
Key Findings
- •Immediate freezing maintained superior progressive motility (71.98%) compared to 8-hour storage at 5°C (52.91%) or 15°C (53.93%)
- •Single Layer Centrifugation (SLC) produced significantly greater post-thaw motility than standard centrifugation across all storage conditions (p ≤ 0.05)
- •Good freezer stallions tolerated 8-hour storage at either temperature, while all bad freezers showed post-thaw motility ≤30% following storage
- •Storage condition, centrifugation method, and individual stallion freezability showed significant interactive effects on post-thaw motility (P=0.0004)