The effect of 2PGF2α and P4eCG protocol of estrus synchronization on reproductive performance of nulliparous Ghezel ewes
The hormonal protocol are used to increase reproductive efficiency in ewes. The aim of study was to investigate the effects of 2PGF2α and compared it with P4eCG in nulliparous Ghezel ewes. A total of 132 nulliparous ewes were randomly divided into three groups. The control group (n=42) did not receive any hormonal treatment. The P4eCG group (n=48) using of intravaginal sponge for a 12-day and injection of 400IU of eCG at the time of sponge removal. The 2PGF2α group (n=42) received the double injection of PGF2α with 9-day interval. Pregnancy detection was done on the 30-35 day of pregnancy using a B-mode ultrasonography. The estrous rate was obtained 100% in all groups. The highest number of nulliparous ewes were in estrus after 48 h after the end of synchronization program (control: 85.8%, 2PGF2α: 85.7%, P4eCG groups: 58.4%). The pregnancy and lambing rates were significantly higher in the P4eCG (85.4% and 85.4%, respectively) and 2PGF2α (83.3% and 83.3%, respectively) groups than in the control group (28.6% and 23.8%, respectively). The litter size and twin rates in the P4eCG treatment group (1.19 and 19.5%, respectively) were significantly higher (P<0.05) compared to the 2PGF2α (1 and 0%, respectively) and control groups (1 and 0%, respectively). The fecundity rate was no statistically significant difference between the P4eCG (1.02±0.08) and 2PGF2α (0.83±0.05) groups (P>0.05). Based on the results, it was concluded that 2PGF2α injection can be employed to synchronize estrus nulliparous ewes in the late breeding season and is a suitable alternative for P4eCG protocol.