Barrett D M W, Bartlewski P M, Duggavathi R, Davies K L, Huchkowsky S L, Epp T, Rawlings N C
Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan, Canada S7N 5B4.
Theriogenology. 2008 Apr 15;69(7):827-36. doi: 10.1016/j.theriogenology.2007.12.010. Epub 2008 Feb 6.
Fertility is often lower in anestrous compared to cyclic ewes, after conventional estrus synchronization. We hypothesized that synchronization of ovarian follicular waves and ovulation could improve fertility at controlled breeding in anestrous ewes. Estradiol-17beta synchronizes follicular waves in cattle. The objectives of the present experiments were to study the effect of an estradiol injection, with or without a 12-d medroxyprogesterone acetate (MAP) sponge treatment, on synchronization of follicular waves and ovulation in anestrous ewes. Twenty ewes received sesame oil (n=8) or estradiol-17beta (350 microg; n=12). Eleven ewes received MAP sponges for 12d and were treated with oil (n=5) or estradiol-17beta (n=6) 6d before sponge removal. Saline (n=6) or eCG (n=6) was subsequently given to separate groups of ewes at sponge removal in the MAP/estradiol-17beta protocol. Estradiol treatment alone produced a peak in serum FSH concentrations (4.73+/-0.53 vs. 2.36+/-0.39 ng/mL for treatment vs. control; mean+/-S.E.M.) after a short-lived (6 h) suppression. Six of twelve ewes given estradiol missed a follicular wave around the time of estradiol injection. Medroxyprogesterone acetate-treated ewes given estradiol had more prolonged suppression of serum FSH concentrations (6-18 h) and a delay in the induced FSH peak (32.3+/-3.3 vs. 17.5+/-0.5 h). Wave emergence was delayed (5.7+/-0.3 vs. 1.4+/-0.7d from the time of estradiol injection), synchronized, and occurred at a predictable time (5-7 vs. 0-4d) compared to ewes given MAP alone. All ewes given eCG ovulated 3-4d after injection; this predictable time of ovulation may be efficacious for AI and embryo transfer.
与处于发情周期的母羊相比，在进行传统的发情同步处理后，处于乏情期的母羊繁殖力通常较低。我们假设，同步卵巢卵泡波和排卵可以提高乏情期母羊在控制配种时的繁殖力。17β-雌二醇可使牛的卵泡波同步。本实验的目的是研究注射雌二醇（无论是否同时进行12天的醋酸甲羟孕酮（MAP）海绵栓处理）对乏情期母羊卵泡波同步和排卵的影响。20只母羊接受了芝麻油注射（n = 8）或17β-雌二醇注射（350微克；n = 12）。11只母羊接受了12天的MAP海绵栓处理，并在取出海绵栓前6天接受了油剂注射（n = 5）或17β-雌二醇注射（n = 6）。在MAP/17β-雌二醇处理方案中，取出海绵栓时，随后分别对不同组的母羊给予生理盐水（n = 6）或eCG（n = 6）。单独使用雌二醇处理后，血清FSH浓度短暂抑制（6小时）后出现峰值（处理组为4.73±0.53 ng/mL，对照组为2.36±0.39 ng/mL；平均值±标准误）。12只接受雌二醇处理的母羊中有6只在注射雌二醇时错过了一个卵泡波。接受醋酸甲羟孕酮处理且注射了雌二醇的母羊血清FSH浓度抑制时间更长（6 - 18小时），诱导的FSH峰值延迟（32.3±3.3小时对17.5±0.5小时）。与仅接受MAP处理的母羊相比，卵泡波出现延迟（从注射雌二醇时起为5.7±0.3天对1.4±0.7天），实现了同步，且在可预测的时间出现（5 - 7天对0 - 4天）。所有接受eCG处理的母羊在注射后3 - 4天排卵；这种可预测的排卵时间可能对人工授精和胚胎移植有效。
