Fertility of mares after unilateral laparoscopic tubal ligation.

This study investigated a special surgical procedure, unilateral laparoscopic tubal ligation (tying of one fallopian tube), on mares to identify its impacts on their fertility rates. The research found that this technique efficiently prevents pregnancy when egg release occurs from the ovary close to the tied tube, without hampering pregnancy establishment when the egg release is from the opposite ovary.

Methodology

• The research involved a randomized prospective clinical trial, comparing pregnancy rates after performing unilateral laparoscopic tubal ligation. This method is a non-biased way of comparing the differences between those mares that received the surgery and those that didn’t.
• The study was conducted on twelve mares of light horse breeds. In six of them, one fallopian tube was surgically tied using a laparoscopic technique, and the remaining six served as non-operated controls.
• Unilateral tubal ligations (UTL) mares were inseminated with 500 million progressively motile sperm during one cycle when the dominant follicle was on the same side as the surgery and another cycle when it was on the opposite side. The control mares were bred regardless of the side of the dominant follicle for two cycles.
• The researchers performed pregnancy tests on days 12, 14, and 16 after ovulation using transrectal ultrasonography.

Results

• The study revealed that none of the mares conceived when an ovulation occurred from the ovary adjacent to the tied tube. Surprisingly, all six mares successfully conceived during the first cycle when ovulation occurred from the non-operated ovary.
• The control group mares that were not subjected to the ligation process, were fertile on 10 out of 12 cycles, which is an 83.3% success rate.

Conclusion

• The study concluded that unilateral tubal ligation is completely effective in preventing pregnancy when ovulation happens from the same side as the tied tube. Importantly, the surgical procedure didn’t interfere with the normal process of pregnancy when ovulation happened from the opposite or untied ovary.
• The authors suggest that such a surgical procedure can be useful for preparing a recipient mare for a process known as gamete intrafallopian transfer. In this procedure, eggs from a donor are placed into the oviduct of the recipient mare which is not tied, allowing her to procreate using the donor’s eggs without the risk of her own eggs fertilizing.