Barrett D M W, Bartlewski P M, Batista-Arteaga M, Symington A, Rawlings N C
Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada S7N 5B4.
Theriogenology. 2004 Jan 15;61(2-3):311-27. doi: 10.1016/s0093-691x(03)00215-2.
A standard dose of 500 IU of eCG is commonly given to progestogen pre-treated anestrous ewes for induction of estrus. Twelve seasonally anestrous and 12 cyclic Western White Face ewes were treated for 12 days with intravaginal sponges impregnated with medroxyprogesterone acetate (MAP). In trials in both the breeding and nonbreeding seasons, six randomly selected ewes were given 500 IU of eCG at sponge removal to determine the effects of low dose of eCG on ovarian antral follicular dynamics and ovulation. Ultrasound scanning and blood sampling were done daily. Treatment with eCG did not have marked effects on antral follicular growth. All ewes ovulated, except for five of six control anestrous ewes. Luteal structures and progesterone secretion were confirmed in all but the control anestrous ewes. In the breeding season, peak progesterone concentrations were greater (P<0.05) in eCG-treated compared to control ewes. Daily serum estradiol concentrations were greater in the periovulatory period in eCG-treated compared to control ewes (treatment-by-day interaction; P<0.05), particularly in anestrus. Progestogen-treated ewes ovulated follicles from several follicular waves, in contrast to ovulations of follicles from the final wave of the cycle in untreated, cyclic ewes. Anestrous ewes exhibited more frequent follicular waves and FSH peaks compared to cyclic ewes after a progestogen/eCG treatment. In conclusion, 500 IU of eCG given after 12 days of progestogen treatment had limited effects on the dynamics of ovarian follicular waves. However, eCG treatment increased serum concentrations of estradiol during the periovulatory period, particularly in anestrous ewes; this probably resulted in the synchronous estrus and ovulation in anestrous ewes.
通常给经孕激素预处理的乏情母羊注射500国际单位的标准剂量孕马血清促性腺激素（eCG）以诱导发情。将12只季节性乏情和12只发情周期正常的西部白面母羊用浸有醋酸甲羟孕酮（MAP）的阴道海绵栓处理12天。在繁殖季节和非繁殖季节的试验中，在取出海绵栓时，随机选择6只母羊注射500国际单位的eCG，以确定低剂量eCG对卵巢窦卵泡动态和排卵的影响。每天进行超声扫描和采血。eCG处理对窦卵泡生长没有显著影响。除了6只对照乏情母羊中有5只外，所有母羊都排卵了。除对照乏情母羊外，所有母羊均证实有黄体结构和孕酮分泌。在繁殖季节，与对照母羊相比，eCG处理的母羊孕酮浓度峰值更高（P<0.05）。与对照母羊相比，eCG处理的母羊在排卵前期的每日血清雌二醇浓度更高（处理与天数交互作用；P<0.05），尤其是在乏情期。与未处理的发情周期正常的母羊在周期最后一波卵泡排卵不同，经孕激素处理的母羊从几个卵泡波中排卵。在孕激素/eCG处理后，乏情母羊比发情周期正常的母羊表现出更频繁的卵泡波和促卵泡素（FSH）峰值。总之，在孕激素处理12天后给予500国际单位的eCG对卵巢卵泡波动态的影响有限。然而，eCG处理增加了排卵前期的血清雌二醇浓度，尤其是在乏情母羊中；这可能导致了乏情母羊同步发情和排卵。
