The use of prostaglandin F2alpha-tham salt in mares in clinical anoestrus.

The study investigates the effectiveness of a drug, prostaglandin F2alpha-tham salt (PGF2alpha), in treating clinical anoestrus in seventy-three Standardbred and Thoroughbred mares. The results showed that this drug effectively restored progesterone levels to normal, induced oestrus, and resulted in successful pregnancies in more than half the treated mares.

Objective of the Research

• The primary aim of this research was to understand the effect of PGF2alpha in treating clinical anoestrus in mares. Clinical anoestrus refers to a state where a mare does not come into estrus, or heat, which is caused by various health issues. It is a significant issue as it prevents reproduction in mares.

Research Methodology

• The research involved 73 Standardbred and Thoroughbred mares who were in clinical anoestrus during the breeding season.
• The mares were divided into four categories: foaling, barren, maiden, and unknown, presumably based on their reproductive history.
• The treatment was administered, and straightforward biological parameters like plasma progesterone levels, behavioural oestrus detection, ovulation occurrence, and successful pregnancy were carefully observed and noted.

Key Findings

• The response to the treatment was notably consistent across all groups of mares.
• Mares in the early stage (Days 2 to 4) of dioestrus did not show a decrease in progesterone levels. However, those in the middle stage (Days 6 to 8) showed a return of those levels to baseline (1 ng/ml) within 24 to 48 hours post-treatment.
• In 93% of the treated mares, progesterone levels returned to normal within 24 to 48 hours. There was no change in levels in the remaining 7% even after 96 hours.
• Behavioural oestrus, a physical manifestation of the mare’s readiness to mate and breed, was detected in 71% of the treated mares within approximately 4.4 days of the treatment.
• Ovulation occurred in 86% of the mares, usually 8-9 days after treatment.
• Of the mares treated with PGF2alpha, 55.5% became pregnant after an average of 1.7 services during the induced estrus, meaning that on average, less than two mating attempts were needed for successful breeding following treatment.

Conclusion of the Research

• Based on the results, the use of prostaglandin F2alpha-tham salt (PGF2alpha) appears to be effective for treating clinical anoestrus in mares.
• It also showed promising results in improving reproductive responsiveness, indicated by the normalisation of hormonal balances, the induction of oestrus, ovulation, and pregnancies.