Sperm transport and distribution in the mare.

Area of Science:

• Reproductive Biology
• Animal Science
• Veterinary Medicine

Background:

• Understanding spermatozoa transport and distribution is crucial for equine artificial insemination success.
• The oestrous cycle stage significantly influences the mare's reproductive tract environment.

Purpose of the Study:

• To investigate the distribution of inseminated spermatozoa within the mare's reproductive tract at different stages of the oestrous cycle.
• To determine the influence of the stallion on spermatozoa recovery rates.

Main Methods:

• Fifty mares were inseminated with spermatozoa from three stallions at specific days of the oestrous cycle.
• Spermatozoa recovery was assessed in the cervix, uterus, and oviducts 12 hours post-insemination.
• Statistical analysis was performed to compare recovery rates across different days and stallions.

Main Results:

• Only a small percentage (0.06-2.21%) of inseminated spermatozoa were recovered.
• Higher spermatozoa recovery was observed in the cervix and uterus on Day 12 compared to other days.
• Greater numbers of spermatozoa were recovered from the oviducts on Days 5 and 8 compared to other days.
• The right oviduct had a higher recovery rate than the left oviduct.
• Stallion significantly influenced the number of spermatozoa recovered from the oviducts.

Conclusions:

• Spermatozoa distribution within the mare's reproductive tract is dynamic and stage-dependent.
• Oviductal spermatozoa recovery is higher during specific phases of the oestrous cycle.
• Stallion characteristics play a role in spermatozoa transport to the oviducts.