The effect of carprofen applied to lactating Assaf breed after mated on the pregnancy rate

Aim of this thesis study, the effects of post-mating administration of carprofen on certain reproductive parameters were investigated in Assaf sheep subjected to estrus synchronization during the breeding season. The animal material consisted of 120 lactating Assaf ewes, aged between 2 and 4 years, with a body weight of approximately 60 kg, a body condition score of 2,75-3,00, a lactation period exceeding 120 days, and having lambed at least once. All ewes were subjected to estrus synchronization using intravaginal sponges containing 60 mg medroxyprogesterone acetate (Esponjavet, Hipra, Spain). After seven days, the sponges were removed, and each ewe received 10 mg PGF2α (Dinolytic, Zoetis, Turkiye) and 400 IU PMSG (Oviser, Hipra, Spain) via intramuscular injection. After the following day, rams were introduced to the flock at a ratio of 1 ram per 8 ewes for a period of 5 days. The mated ewes were randomly divided into two groups: the carprofen group (KPG; n=60) received 1,4 mg/kg subcutaneous carprofen (Veniven, Verano, Turkiye) on day 9 postmating, while the control group (KG; n=60) received no treatment. Blood samples were collected on days 9, 11, 13, and 17 post-mating to determine serum progesterone (P4) levels. Pregnancy diagnosis was performed between days 35-40 post-mating using a 6 MHz linear-array real-time transabdominal ultrasound (Falco Vet, Pie Medical, The Netherlands). The pregnancy rates in the KPG and KG groups were found to be 65,5% and 60,8%, respectively (P>0,05). The rates of multiple pregnancies and the mean number of fetuses per pregnancy were 63,1% and 48,4%; and 1,65 and 1,48, respectively (P>0,05). In pregnant ewes, the P4 level in the KPG group was significantly higher on day 17 compared to days 9 and 11 (P<0,001). In the KG group, P4 levels on days 13 and 17 were higher than on day 9 (P<0,05). As a result, it was determined that the administration of carprofen on day 9 post-mating in lactating Assaf ewes did not cause a statistically significant difference in pregnancy rate, multiple pregnancy rate, or number of fetuses per pregnancy; however, a numerical increase was observed. Additionally, current data suggest that carprofen may support corpus luteum (CL) formation. It is concluded that this numerical improvement in pregnancy rate may be of practical importance in biotechnological applications such as artificial insemination and embryo transfer, especially in highproducing dairy sheep, where pregnancy outcomes are of critical importance. Therefore, carprofen use could be considered a potential reproductive management strategy in such cases.