USE OF MEFENAMIC ACID IN EQUINE EMBRYOS RECIPIENTS

Abstract

In order to extend an acceptable interval between ovulation of the recipient and the day of the
embryo transfer (ET), the purpose of this study was to evaluate the effect of mefenamic acid
in the ability to maintain corpus luteum function in recipient mares that were on Day 10 (D10)
of the estrous cycle, and to verify the pregnancy rate after embryo transfer. 48 embryos were
transferred into recipients on Day 10 of the cycle divided into three experimental groups:
Group 1 control (n = 18); Group 2 (n = 15) recipients treated with 1g mefenamic acid orally
since the eighth until the tenth sixth days after ovulation; Group 3 (n = 15) recipients treated
with 1g mefenamic acid orally on day of transfer and for two more days. Six days after ET,
pregnancy was confirmed by ultrasound and repeated at 30 days. For analysis of percentages
of pregnancy and classification uterine on ET day was used Fisher's exact test and the values obtained from the serum progesterone was used ANOVA followed by Tukey test.The control
group showed a 33.3% pregnancy rate (6/18). Groups 2 and 3 presented 40.0% (6/15) and
33.3% (5/15), respectively. In non-pregnant mares, all three groups showed a progressive
decrease in the mean concentration of progesterone significantly from day 12 post ovulation,
without interference in the time of the occurrence of luteolysis. The pregnancy rate in
recipients on Day 10 showed satisfactory rates in recipients with good uterine tone and neck
on the day of ET. It is concluded that mefenamic acid did not prevent luteolysis and did not
improve pregnancy rates of recipients on day 10 of the estrous cycle