The effect of carprofen administration post-mating on conception rate in lactating Assaf ewes

The aim of this study was to reduce embryonic loss and improve conception rates in lactating ewes during transition to breeding season through post-mating administration of carprofen. An intravaginal sponge containing 60 mg medroxyprogesterone acetate (Esponjavet®, Hipra, Turkey), was administered in all Assaf ewes (n = 126) for a period of seven days. The vaginal sponge was then removed and 450 IU of eCG and 10 mg/ewe of PGF2α were injected intramuscularly. The rams were introduced to the flock at a ratio of 1:6 (i.e. 1 ram per 6 ewes) for a 5-day mating period. After the withdrawal of the rams, the ewes were randomly divided into two groups: the carprofen group (n = 55) and the control group (n = 71). The ewes of carprofen group received a dose of carprofen (1.4 mg/Kg s.c.), whereas those of control group received saline (1 mL) on day 6 after the end of estrus synchronization. The diagnosis of pregnancy was performed on day 35 following the removal of the ram using real-time ultrasonography. The results indicated that the conception rate was significantly higher in the carprofen group (65 %, 36/55) than in the control group (47 %, 34/71) (P < 0.05). The rate of multiple pregnancies was 30 % (11/36) in the carprofen group and 12 % (4/34) in the control group, while the mean number of fetuses per pregnancy was recorded as 1.30 and 1.11, respectively (P > 0.05). In conclusion, the post-mating administration of carprofen, a non-steroidal anti-inflammatory drug with a prolonged half-life, has been found to improve conception rates in ewes.