Effect of breed and other animal-related factors on conception rate to artificial insemination with frozen semen in mares in Ethiopia.

The study investigated the impact of animal breed and other characteristics on the conception rate of mares in Ethiopia when using artificial insemination with frozen semen. The research found that breed, ovulation location, follicle size, and frequency of insemination influence success rates, while factors such as age and body condition had no significant effect.

Study Setting and Methodology

• The research was carried out at the Balderas Sport Horses and Recreational Center in Addis Ababa, Ethiopia, between January and June 2018.
• The study involved both local and crossbreed mares. Their estrus behavior was characterized by teasing and ultrasound was used to detect any coming ovulation events.
• The horses were inseminated shortly after ovulation, typically within 6-9 hours, using frozen and then thawed semen.

Findings of the Study

• The overall conception rate from the frozen semen was 71.43%, with 72.73% for the crossbreed mares and 70% for the local breed mares.
• The age and body condition score (a rating of the animal’s fitness) did not significantly affect the conception rate.
• Conception rate was slightly higher when ovulation originated from the right ovary compared to the left.
• When the preovulatory follicle (the sac in the ovary where the egg grows) was less than or equal to 45mm in diameter, a higher conception rate was achieved than with larger follicles.
• A better conception rate was obtained with a higher number of inseminations per pregnancy attempt. The average was approximately 2.2 services per conception.
• However, more inseminations were needed for the local breed mares (2.7) than for the crossbreeds (1.8), and similarly for mares in poorer body condition compared to those in better condition.

Conclusions Drawn

• In general, increasing the number of inseminations boosted the conception rate. And there were significant variations in this effect depending on the breed of the mare.
• The researchers concluded that better mare management aimed at improving their physical condition could potentially decrease the number of required inseminations to achieve conception.