Effect of surgical removal of endometrial cups on concentrations of chorionic gonadotrophin and subsequent fertility in the mare.

This research investigated the impact of surgical elimination of endometrial cups on the levels of horse chorionic gonadotrophin and future fertility in mares. The findings demonstrated a decrease in the chorionic gonadotrophin concentrations post-surgery, with successful pregnancy reestablishment observed in some mares.

Research Methodology

• The researchers conducted an experiment on seven pregnant mares. This involved general anaesthesia, laparotomy, and hysterotomy and removal of a 50-day conceptus.
• The uterine horn’s eversion via the hysterotomy site enabled direct visualisation and electrosurgical elimination of the endometrial cup tissue in five of the mares. The remaining two mares’ endometrial cup tissue was left untouched.
• Two other pregnant mares without surgery served to be the control group for the study.
• The team started efforts to reinitiate pregnancy in the mares 20 days post-surgery.

Data Collection and Analysis

• Serum samples were collected before the surgery and during the post-operative period. These were analysed for concentration levels of horse chorionic gonadotrophin (CG) using a radioimmunoassay.
• The average weight and area of the removed tissue was also noted.
• The concentration levels of CG were found to be the highest at the time of cup removal (50 days), followed by a gradual decline.
• The researchers discovered that the peak concentrations of CG at the time of surgery did not linearly correlate with the mass of excised cup tissue.
• Peak CG concentrations were observed 68 days post-conception in the mares that underwent cup tissue removal surgery, with a varying rate of disappearance.
• Further observations revealed mares exhibiting behavioural oestrus and ovulation post-surgery. Successful pregnancy was observed in three of these mares, associated with low CG concentration levels.

Findings and Conclusion

• The study found that surgical removal of endometrial cups resulted in a decrease in the concentrations of CG, especially after the surgery.
• The results also showed a possibility of successful reestablishment of pregnancy after such a procedure.
• However, as only some of the mares became pregnant following the operation it suggests that while this surgery may not impede fertility completely, it may have a significant impact.
• Further research is needed to gain deeper insights into the full implications of the removal of endometrial cups on horse fertility.