03153naa a2200421 a 450000100080000000500110000800800410001902400410006010000210010124501400012226000090026252019290027165000220220065000140222265000170223665000100225365000200226365000170228365000140230065000210231465000100233565000150234565000170236065000270237765300090240465300320241365300090244565300280245465300220248270000220250470000220252670000270254870000200257570000200259570000230261570000200263877300730265820466562017-08-23       2016    bl uuuu     u00u1 u    #d7 a10.1016/j.domaniend.2015.07.0022DOI1 aBALARO, M. F. A.  aPotential role for GnRH in the synchronization of follicular emergence before the superovulatory Day 0 protocol.h[electronic resource]  c2016  aAbstract: The ability of gonadotropin-releasing hormone (GnRH) to synchronize ovulation and new follicular wave emergence before a "superovulatory Day 0" protocol was assessed in Santa Inês ewes. For estrus synchronization, a 60-mg medroxyprogesterone acetate sponge was inserted for 6 d. One day before sponge removal, 37.5-ug d-cloprostenol and 300 IU equine chorionic gonadotropin were injected intramuscularly (i.m.). After sponge removal, ewes were assigned to the following 3 groups: (1) GC-1 mL saline at 12 h (n = 10); (2) G24h-0.025-mg lecirelin (GnRH agonist) i.m. at 24 h (n = 10); or (3) G36h-0.025-mg lecirelin i.m. at 36 h (n = 9). Ovarian ultrasonography was conducted to assess follicular dynamics. Blood was collected to determine plasma concentrations of progesterone and estradiol. Females from G36h and GC had a greater (P &lt 0.05) estrous response than those from the G24h group (78.0 and 90.0 vs 0.0%, respectively). Ewes from G24h and G36h had earlier (P &lt 0.05) ovulation (48.0 ± 10.2 and 56.7 ± 5.7 h) compared with those from Gc (64.1 ± 9.7 h). The mean number of ovulations per ewe was greater (P &lt 0.05) in Gc (1.9 ± 0.6) and G36h (2.0 ± 1.0) than G24h (1.2 ± 0.4). Plasma concentrations of progesterone and estradiol differed over time. Follicular growth during the postovulatory day was affected (P &lt 0.05) by day of the estrus cycle as well as by the interaction (P &lt 0.05) of treatment and day of the estrus cycle. There was a larger (P &lt 0.05) population of medium follicles during the first 24 h after the ovulation in G24h compared with Gc, and there was an absence of large follicles in G36h between 36 and 72 h after ovulation. In conclusion, the use of GnRH agonist at 36 h more efficiently synchronized ovulation and promoted the absence of dominant follicles during early diestrus and may be used at the start of superovulatory treatment at 80 h in Santa Inês ewes.  aOvarian follicles  aOvulation  aProgesterone  aSheep  aUltrasonography  aCiclo estral  aEstradiol  aHormônio animal  aOvino  aOvulação  aProgesterona  aSincronização do cio  aGnRH  aMedroxyprogesterone acetate  aMOET  aOestrus synchronization  aRaça Santa Inês1 aFONSECA, J. F. da1 aBARBOSA, T. G. B.1 aSOUZA-FABJAN, J. M. G.1 aFIGUEIRA, L. M.1 aTEIXEIRA, T. A.1 aCARVALHEIRA, L. R.1 aBRANDÃO, F. Z.  tDomestic Animal Endocrinology, Stonehamgv. 54, p. 10-14, Jan. 2016.