Synchronization of estrus in field conditions using Progestagen sponge, GnRH, and PGF2α in Barki ewes during breeding season

الملخص EN

This study was conducted to evaluate reproductive performance of Barki ewes subjected to three estrus synchronization programs in field conditions during breeding season.

For this purpose, 36 cycling ewes were divided into 4 groups according to the program assigned: Group SeCG (n=10): received intravaginal progesterone sponge (40 mg Fluorogestone acetate, Chrono-gest®, Intervet International) for 7 days, at time of sponge removal, each ewe received i.m injection of 500 IU eCG (Folligon®, Intervet International); Group PG-PG (n=10): received double injections of 250μg Cloprostenol (PGF2α analogue, Estrumate®, Intervet International) 11 days apart; Group GPG (n=6): received 4μg Buserelin by i.m injection on day 0 (GnRH analogue- Receptal®, Intervet International), on day 5 animals received 250μg Cloprostenol followed by 4μg Buserelin by i.m injection on day 7; Group C (n=10): served as control group that did not receive any treatment.

Results showed that estrus induction rate was significantly high in SeCG group that was recorded at 100% (P<0.05), while it was 90%, 60%, and 50% for PG-PG, C and GPG respectively.

Estrus synchrony was more uniform in SeCG group as 70% of ewes exhibited estrus around 24-36 hrs from end of treatment.

There was no significant difference among groups in pregnancy and lambing rate (p>0.05).

Pregnancy rates were 100%, 90%, 88.9%, and 83.3% for GPG, SeCG, PG-PG, and C group respectively.

Conclusion, from results we conclude that intravaginal progesterone sponge for 7 days+500IU eCG at sponge removal is convenient for estrus synchronization of ewes raised in field conditions during breeding season.

Moreover, reproductive and fertility parameters recorded in the current study are acceptable and within values reported previously in farm conditions.