Effects of endometrial biopsy, uterine culture, and cervical dilatation on the equine estrous cycle.

This study explored the impacts of endometrial biopsy, uterine culture, and cervical dilation on the equine estrous cycle. Research findings showed a marked decrease in serum progesterone concentration and a shortened interestrous period following these procedures, suggesting potential effects on estrus duration and luteum regression.

Background and Methods

• The experiment was conducted with a sample of 10 mares, and data was collected before and after endometrial biopsy, uterine culture, or cervical dilation were performed.
• The aforementioned procedures took place on specific days after estrus: day 4 for endometrial biopsy and culture, and days 1 and 3 for manual cervical dilation.

Results

• After the endometrial biopsy and culture performed on day 4, there was a marked drop in serum progesterone concentration, significantly reducing the interestrous interval and prolonged estrus.
• Applying the same procedures on days 1 and 3 or by dilating the cervix on day 4 also lowered the serum progesterone concentration within 24-48 hours, leading to a shortened diestrus and extended subsequent estrus.

Second Experiment

• A follow-up experiment revealed similar effects on the estrous cycle and diestrous period following an endometrial biopsy on day 4 after estrus.
• Notably, this manipulation also led to an extended subsequent estrus.

Conclusion

• The findings suggest that the corpus luteum regression may be stimulated by the procedures of endometrial biopsy, uterine culture, and cervical dilatation, leading to the subsequent occurrence of estrus and ovulation in the mare.
• This could provide valuable insights into reproductive veterinary practices and might help in developing more effective fertility treatments related to the equine estrous cycle.