87 Effect of Treatment with Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) on Pregnancy Rates of Recipient Alpacas Post-Embryo Transfer

Abstract

The aim of the study was to improve the pregnancy rate in recipient alpacas using nonsteroidal anti-inflammatpry druds (NSAIDs) at time of embryo transfer. Because most NSAIDs are non-selective inhibitors of cyclooxygenases, which are the rate-limiting enzymes in the formation of prostaglandins, such treatment could temporarily block the production of prositaglandin F_2α (PGF_2α) and hence maintain corpus luetum (CL) activity long enough to support embryo development and pregnancy. The experiment was carried out in the Peruvian southern highlands (4,100 m elevation). Thirty-one adult alpaca donors were subjected to superovulation and embryo flushing as described previously (Vivanco-Mackie 2013 Proc. 29th Annu. Mtg. AETE, Istanbul, pp. 43-74; http://www.aete.eu/index.php/publications-aete/proceedings/2013/file). From the collected embryos, 20 grade A embryos were selected and transferred fresh into the recipients of the 2 experimental groups. All embryos were collected and transferred at 6.5 days post-mating of the donors with one embryo transferred per recipient. Recipient alpacas (n = 20) were synchronized and induced to ovulate after a selection made by ultrasonography, selecting as recipients the alpacas with follicles >8 mm and then exposing them to vasectomized males followed by IM injection of gonadotropin-releasing hormone (GnRH, 0.0084 mg of acetate of buserelin). Embryo transfers were made by laparoscopically aided laparotomy 6.5 days after ovulation induction as this method has been demonstrated to be more effective in previous trials compared with transcervical non-surgical transfers. At the time of embryo transfer, the recipients were randomly assigned to 1 of the 2 treatments according to the NSAID injected immediately after embryo transfer: Treatment 1 (10 alpacas) was an IM injection of meloxicam at 0.5 mg/kg of body weight; treatment 2 (10 alpacas) was an IM injection of tolfenamic acid at 3 mg/kg of body weight. At the pregnancy test by ultrasound scanning on Day 58 post-transfer, 30% (3/10) of the recipients had a live fetus in treatment 1, whereas treatment 2 had only 10% (1/10).The difference was not significant (P > 0.05) based on Chi-squared analysis. Th historical pregnancy rate obtained with fresh embryos transferred using the same technique and on the same farm where the comparison between NSAIDs was performed was 28.6% at 58 days post-transfer (Vivanco-Mackie et al. 2015 Reprod. Fertil. Dev. 27, 173 abst). Results suggest that there is no difference between tolfenamic acid and meloxicam in their effect on pregnancy rates in alpacas receiving fresh embryo transfers. Compared with historical data of nontreated recipients, results of the present experiment may indicate that the use of NSAIDs at the time of embryo transfer does not improve pregnancy rates in alpaca fresh embryo recipients. However, additional research studies with greater numbers of recipients and an untreated control group are necessary to confirm the preliminary results of the present study.

The study was funded by the ‘INNOVATE PERU’ program of the Peruvian Government.