Effects of seminal plasma on uterine polymorphonuclear dynamics and fertility of jennies inseminated with glycerol-free, frozen-thawed donkey semen.
Authors: Vargas Jeimmy Hernández, Zarco Luis, Salinas Elizabeth Morales, Urías-Castro Cristian, Boeta Myriam
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Seminal Plasma and Uterine Inflammation in Frozen Donkey Semen Frozen-thawed donkey semen consistently triggers excessive uterine inflammation in jennies, compromising fertility outcomes—a challenge this 2025 study addressed by examining whether seminal plasma could modulate the inflammatory response. Researchers inseminated 39 jennies across three groups (fresh semen, frozen-thawed semen alone, and frozen-thawed semen with added seminal plasma) and tracked polymorphonuclear neutrophil (PMN) dynamics via uterine cytology at 8, 24, and 48 hours post-insemination. Whilst frozen-thawed semen alone provoked the most aggressive inflammatory spike at 8 hours (90.7% PMN versus 68.9% for fresh semen), the addition of seminal plasma accelerated PMN clearance between 24 and 48 hours, a pattern that correlated with pregnancy success—pregnant jennies showed significantly lower PMN percentages at 48 hours (44.4%) compared to non-pregnant animals (64.8%). The findings suggest that supplementing frozen-thawed donkey semen with seminal plasma represents a practical intervention to suppress maladaptive inflammation without eliminating the protective immune response entirely, potentially improving conception rates in assisted breeding programmes. For practitioners working with donkey reproduction, this indicates that seminal plasma recovery and addition during the thawing process warrants serious consideration as a cost-effective refinement to current freezing protocols.
Read the full abstract on PubMed
Practical Takeaways
- •When using frozen-thawed donkey semen for jenny insemination, adding seminal plasma to the thawed semen may improve conception rates by reducing prolonged uterine inflammation
- •Monitor jennies receiving frozen-thawed semen for extended inflammatory responses; those with slower polymorphonuclear clearance at 48 h post-insemination are at higher risk of subfertility
- •Fresh semen remains superior to frozen-thawed semen for jenny insemination, but seminal plasma addition offers a practical way to partially mitigate the immunological disadvantages of cryopreservation
Key Findings
- •At 8 h post-insemination, frozen-thawed semen (FTS) induced higher polymorphonuclear cell percentage (90.7%) compared to fresh semen (68.9%), with seminal plasma addition showing intermediate levels (82.7%)
- •Addition of seminal plasma to frozen-thawed semen resulted in faster polymorphonuclear clearance from 24-48 h post-insemination
- •Pregnant jennies demonstrated significantly lower polymorphonuclear percentages at 48 h (44.4%) compared to non-pregnant jennies (64.8%)
- •Seminal plasma supplementation may improve fertility by accelerating uterine immune cell clearance after insemination