The Effect of Short-Term or Long-Term Progesterone-Based Estrus Synchronization on Fertility Parameters in Tuj Ewes outside the Breeding Season.

The objective of this study was to investigate the impact of estrus synchronization on certain fertility parameters in Tuj ewes during the non-breeding season, using short-term (ST) or long-term (LT) progesterone (P4)-impregnated sponge and equine chorionic gonadotropin (eCG). Forty-eight clinically healthy Tuj ewes were selected and divided into three groups: Group I (G1, n=15), Group II (G2, n=18), and Group III (G3, n=15). G1 and G2 received hormonal treatment with a P4-impregnated sponge inserted into the vagina on day 0, and 500 IU eCG was administered intramuscularly five or ten days later, respectively. The sponges were removed from the vagina seven days after insertion for G1 and 12 days after insertion for G2. G3 did not receive any hormone treatment. All groups were exposed to the ram 24 hours after sponge removal. Estrus was monitored every six hours for five days, and pregnancy was confirmed by transrectal ultrasonography. The estrus rate, estrus onset time, and pregnancy rate were significantly different between G1 and G3 and between G2 and G3 (p<0.05). However, there was no difference between the treatment groups (G1 and G2) in terms of fertility parameters (p>0.05). In conclusion, ST or LTP4-impregnated vaginal sponge treatment was equally effective on fertility parameters in Tuj ewes during the non-breeding season. [ABSTRACT FROM AUTHOR]