Fertility of mares after unilateral laparoscopic tubal ligation.
Authors: McCue P M, Hendrickson D A, Hess M B
Journal: Veterinary surgery : VS
Summary
# Editorial Summary Researchers at Colorado State University developed a laparoscopic technique for unilateral tubal ligation in mares and assessed whether the procedure reliably prevented pregnancy when ovulation occurred ipsilateral to the ligated oviduct, whilst preserving fertility on the contralateral side. Using a randomized prospective design, they ligated one oviduct in six mares and monitored pregnancy rates across two breeding cycles—one with ovulation ipsilateral and one contralateral to the ligation—comparing outcomes against six control mares bred normally. The ligated oviduct proved 100% effective at preventing pregnancy when the ovary on that side ovulated (0/6 pregnancies), whilst all six mares conceived when ovulation occurred from the opposite ovary on the first cycle, matching the control group's conception rate of 83.3% (10/12 cycles). This technique has practical value for recipient mares undergoing gamete intrafallopian transfer (GIFT), as unilateral tubal ligation allows controlled prevention of the recipient's own oocyte fertilisation whilst maintaining luteal function and enabling transfer of a donor oocyte into the patent contralateral oviduct. For equine reproduction specialists, this procedure represents a valuable refinement in assisted reproductive techniques, though practitioners should note that side-specific ovulation prediction remains essential for reliable application.
Read the full abstract on PubMed
Practical Takeaways
- •UTL offers an alternative to systemic contraception for mares that need controlled breeding or recipient preparation, as it completely blocks pregnancy from one ovary while preserving normal cycles on the other side
- •Practitioners should counsel owners that this technique reliably allows ovulation and corpus luteum formation (maintaining hormone production) while selectively preventing fertilization, useful for GIFT procedures or managing mares that need to cycle but not conceive
- •The procedure requires laparoscopic surgical capability but provides permanent, side-specific contraception without recurring medication or hormone-related complications
Key Findings
- •Unilateral tubal ligation was 100% effective at preventing pregnancy when ovulation occurred from the ipsilateral ovary (0/6 pregnancies)
- •All 6 mares with contralateral ovulation became pregnant on the first cycle after ligation
- •Control mares achieved pregnancy in 83.3% of cycles (10/12), indicating the ligation procedure did not affect corpus luteum formation or contralateral fertility
- •Laparoscopic tubal ligation is a viable technique for selective reproductive control without systemic hormonal effects