Effect of the Flunixin Meglumine on Pregnancy Rates in an Equine Embryo Transfer Program

Abstract

a b s t r a c tDuring the equine embryo transfer (ET), manipulation of the recipients cervix can stimulate the release of prostaglandin F2a by the uterine environment. Nonsteroidal antiinflammatory drugs such as flunixin meglumine (FM) are frequently used in order to prevent a potential luteolysis. However, despite the reduction of inflammatory reaction and release of prostaglandins, the benefits of FM in pregnancy rates (PRs) of mares submitted to ET are not conclusive, and there is no information about the early pregnancy loss (EPL) rate after FM injection. The objective of this study was to evaluate the effect of FM in the PR and EPL in embryo-recipient mares. The data from 409 ET from a commercial breeding center were used, which 179 mares formed the control group (CG) and 230 recipients received the treatment of FM 1.1 mg/kg immediately after ET. There was no difference (P > .05) in PRs at 15 days (70.95% in the CG and 75.22% in treated mares) and 60 days (65.92% in CG and 65.22% in FM treated mares). However, there was a trend in the increase of early the pregnancy loss rate in mares that received FM (P ¼ .0852). From the results of the present experiment, FM does not improve the PR in embryo-recipient mares.

Non‐surgical embryo transfer technique and recipient mare pregnancy rate

“…The embryos were collected on day 8 or 9 ater ovulation and were transferred into recipient mares that ovulated from one day before and up to ive days ater the donor mare, with the The reason for the signiicant improvement in recipient pregnancy rate using the Wilsher forceps-assisted transfer remains unknown. Manipulation of the cervix has been associated with prostaglandin release that may result in luteolysis and pregnancy failure, 14 or ejection of the embryo from the uterus through the cervix. 7 In 2016, McCue studied 218 recipient mare cycles, and measured serum progesterone in these mares at ive days ater ovulation.…”

“…12 However, the relatively small percentage of recipient mares with low progesterone levels suggests that other factors such as poor embryo quality, post-transfer non-infectious or infectious endometritis, or failure of the maternal recognition of pregnancy by the recipient may better explain subsequent pregnancy rates. 14 Whether concurrent medication use increases pregnancy rates using conventional transfer is undecided. The study by Cuervo-Arango and others 13 reported a low but similar percentage of mares with signs of luteal failure in the conventional and Wilsher forceps-assisted transfer groups, suggesting that lower rates of luteal failure was not the cause of the improvement in recipient pregnancy rate.…”

“…Whether cervical manipulation is sufficient to cause sufficient prostaglandin release to cause luteolysis is not clear 15 . This is supported by investigations that show an inconsistent effect of non‐steroidal anti‐inflammatory medications at the time of embryo transfer on subsequent recipient pregnancy rates 14 . A persistently low level of progesterone is either a reflection of poor luteal formation or significant premature endometrial prostaglandin release resulting in luteal regression 12 .…”

“…A persistently low level of progesterone is either a reflection of poor luteal formation or significant premature endometrial prostaglandin release resulting in luteal regression 12 . However, the relatively small percentage of recipient mares with low progesterone levels suggests that other factors such as poor embryo quality, post‐transfer non‐infectious or infectious endometritis, or failure of the maternal recognition of pregnancy by the recipient may better explain subsequent pregnancy rates 14 …”