Author(s): SOUZA-FABJAN, J. M. G.; BALARO, M. F. A.; BARBOSA, T. G. B.; FONSECA, J. F. da; FIGUEIRA, L. M.; TEIXEIRA, T. A.; CARVALHEIRA, L. R.; BRANDÃO, F. Z.

Summary: The role of GnRH to synchronize ovulation and follicular emergence previous to superovulatory protocol, started on the first day of the estrous cycle (Day 0), was assessed in Santa Inês ewes. For estrus synchronization, 60 mg medroxyprogesterone acetate sponges were used for 6 d plus 37.5 ?g d-cloprostenol and 300 IU eCG at fifth day. After sponge removal, ewes were assigned to three treatments: GControl ? saline at 12 h (n = 10); G24h ? GnRH at 24 h (n = 10); or G36h ? GnRH at 36 h (n = 9). In conclusion, considering the beneficial effects of G36h in synchronizing ovulation and to promote the absence of dominant follicles in the first days of estrous cycle. According to data obtained, the best time to start the superovulatory treatment, known as "Day 0", could be 80 h after sponge removal (56 h for the occurrence of ovulation plus 24 h to reset dominant follicles), in the induction of synchronized estrus, for Santa Inês ewes.

Publication year: 2015

Types of publication: Abstract in annals or event proceedings

Unit: Embrapa Goats & Sheep

Keywords: Ciclo estral, Estradiol, Ewes, Lecirelin, MOET, Oestrous cycle, Ovino, Ovulation, Ovulação, Progesterona, Progesterone, Reproduction, Reprodução animal, Santa Inês, Sheep, Superovulation, Superovulação, Synchronization