[Effect of the administration of PGF2 alpha synchronously with insemination on the pregnancy rate in mares in an insemination program].

This research investigates the effect of prostaglandin F2 alpha (PGF2 alpha), a hormone responsible for initiating uterine contractions during mating, on improving pregnancy rates in mares when delivered in sync with artificial insemination (A.I.). The study found that administering this hormone did not significantly impact pregnancy rates, with additional factors influencing the result include stallion, semen quality, and the frequency of insemination per cycle.

Introduction

• The study was conducted to explore possible ways of boosting pregnancy rates in mares through the concurrent administration of PGF2 alpha, a hormone associated with uterine contractions, with A.I. procedure.
• Previous research had suggested the role of uterine contractions in enhancing the transportation of sperm within the female genital tract.

Method

• The investigation involved 346 warmblood-mares, aged between two to 20 years, from a private stud farm. The test was carried out in the breeding season of 1996.
• PFG2 alpha (in the form of Dinoprost) was either injected intramuscularly or delivered intrauterine and then compared with a placebo treatment.
• The participating mares were divided into two groups: group A with mares undergoing spontaneous ovulation and group B in which ovulation was initiated by a GnRH-analog-implant (Deslorelin).
• The selection of treatment (intramuscular or intrauterine) for each mare was executed randomly.

Results

• The pregnancy rates following the first insemination cycle proved to be statistically similar across the groups, barring group B2, where the mares were given a placebo intramuscularly.
• In mares that were repeatedly treated during the oestrus period, no significant differences in pregnancy rates were recorded between treatment and control groups.
• Additional factors like the stallions contributing the semen, the quality and age of the semen, and frequency of insemination during each oestrus period had minor impacts on the results.

Conclusion

• The study concludes that the application of PGF2 alpha, synchronized with A.I., does not yield a significant enhancement in pregnancy rates in mares.
• Other influential factors contributing marginally to the results include the quality of the semen, the stallion from which it originated, and the number of inseminations each oestrus.