Induction of ovulation in cyclic mares by administration of a synthetic prostaglandin, fenprostalene, during oestrus.

The study examines the impact of administering synthetic prostaglandin fenprostalene to cyclic mares during their oestrus cycle. The research suggests that fenprostalene effectively hastens the time of ovulation in these horses.

Study Design and Methodology

• This study involved eight mares over four oestrus cycles. In alternate oestrus periods, the mares were either given fenprostalene (250 micrograms) or saline 60 hours after the onset of oestrus.
• The onset of oestrus and stage of cycle were determined through daily teasing, palpation, and ultrasonography until treatment time.
• The scientist monitored follicular development through 12-hour interval checks to confirm ovulation.
• They also inspected daily serum progesterone concentrations.

Findings and Results

• The study found that fenprostalene significantly decreased the interval from treatment to ovulation, with results showing 41.25 hours for treated mares vs 73.50 hours for untreated mares.
• The duration of oestrus was also significantly decreased in the treated mares (5.63 VS 6.88 days).
• The fenprostalene did not impact the duration of dioestrus which remained similar across the study group.
• The hormone treatment did not affect serum progesterone concentrations at the onset of oestrus, treatment time, or examination before ovulation.
• Follicular size was mostly unaffected at the start of oestrus or pre-ovulation.
• While there was no significant difference found in follicle size at treatment time (considering a possible horse effect), the study noted a significant difference in size when the horse effect was not factored in.
• The researchers observed that 81% of the treated mares had ovulated 48 hours post-treatment compared to 31% of untreated mares.

Conclusion

• The findings of this research indicate that fenprostalene efficiently fosters a quicker ovulation time in cyclic mares.