First pregnancies in jennies with vitrified donkey semen using a new warming method

Area of Science:

• Reproductive biology
• Animal science
• Veterinary medicine

Background:

• Sperm vitrification is a novel technique with limited fertility data in equids.
• Conventional semen freezing methods can impact sperm quality and lead to uterine inflammation post-insemination.

Purpose of the Study:

• To develop and evaluate a new warming technique for vitrified donkey semen.
• To compare the uterine inflammatory response and fertility of vitrified versus conventionally frozen semen in jennies.

Main Methods:

• Donkey sperm was vitrified and warmed using different temperatures and times (37°C/30s, 43°C/10s, 60°C/5s).
• Sperm motility, membrane integrity, and DNA integrity were assessed.
• Jennies were artificially inseminated with either vitrified or frozen semen, and pregnancy rates and uterine polymorphonuclear neutrophil (PMN) concentrations were measured.

Main Results:

• Warming at 43°C for 10 seconds yielded optimal sperm motility compared to other temperatures.
• No significant difference in PMN concentration was observed between vitrified and frozen semen groups immediately after insemination.
• PMN levels decreased faster in jennies inseminated with vitrified semen, and pregnancy rates were higher (22%) compared to frozen semen (10%).

Conclusions:

• Direct warming of vitrified donkey semen in a water bath at 43°C for 10 seconds is effective.
• This method reduces the uterine inflammatory response and shows potential for improved pregnancy rates in equine artificial insemination.