This study was conducted in ewes to assess effects of human chorionic gonadotropin (hCG) administration after imposing an estrous induction treatment regimen. Ewes (n = 115) were treated with a 60 mg medroxyprogesterone-intravaginal-sponge for 6 d plus 200 IU of equine chorionic gonadotropin (eCG) im and 37.5 μg d-cloprostenol im 36 h before sponge removal (Day 0). After natural mating, ewes having at least one corpus luteum (CL; n = 108) were administered either 1 mL of saline (G-Control; n = 53) or 300 IU of hCG (G-hCG; n = 55) on Day 7.5 after sponge removal (Day 0). Ovarian ultrasonography and blood collection were performed on Days 7.5, 13.5, 17.5, 21.5, and 30.5. Accessory CL (aCL) were observed in 81.5 % (G-hCG) and 0.0 % (G-Control) of ewes (P = 0.0001). Diameter, area, and volume of luteal tissue were greater (P < 0.05) in G-hCG from Day 13.5 to 30.5. Progesterone (P₄) concentrations were greater (P < 0.05) on Days 13.5, 17.5, 21.5 and 30.5 for ewes of the G-hCG group. Pregnancy percentage was similar (P = 0.25) between groups [47.1 % (G-control) compared with 60.0 % (G-hCG)], although total number of lambs produced by estrous synchronized ewes was greater (P = 0.005) in ewes of the G-hCG group (90.9 % compared with 66.0 %). In conclusion, hCG administration 7.5 days after sponge removal from Morada Nova ewes during the non-breeding season is an effective treatment to induce aCL formation, improve luteal tissue biometry and P4 concentrations, and to enhance the total number of lambs born.

本研究在母羊中进行，以评估在实施发情诱导治疗方案后施用人绒毛膜促性腺激素 (hCG) 的效果。母羊 ( n = 115) 用 60 毫克甲羟孕酮阴道内海绵治疗 6 天，外加 200 IU 马绒毛膜促性腺激素 (eCG) im 和 37.5 μg d-氯前列醇在取出海绵前 36 小时（第 0 天）。自然交配后，给至少有一个黄体（CL；n = 108）的母羊注射 1 mL 生理盐水（G-Control；n = 53）或 300 IU hCG（G-hCG；n= 55) 在海绵去除后的第 7.5 天（第 0 天）。在第 7.5、13.5、17.5、21.5 和 30.5 天进行卵巢超声检查和采血。在 81.5% (G-hCG) 和 0.0% (G-Control) 的母羊中观察到辅助性 CL (aCL) ( P = 0.0001)。从第 13.5 天到第 30.5 天，G-hCG中黄体组织的直径、面积和体积更大（P < 0.05）。G-hCG 组的母羊在第 13.5、17.5、21.5 和 30.5 天的孕酮 (P ₄ ) 浓度更高 ( P < 0.05)。怀孕百分比是相似的（P = 0.25）基团[47.1％（G-对照）与60.0％（G-HCG）相比]，尽管通过同步发情母羊产生的羊羔的总数为更大（间P= 0.005) 在 G-hCG 组的母羊中（90.9 % 与 66.0 %）。总之，在非繁殖季节从 Morada Nova 母羊身上取出海绵后 7.5 天施用 hCG 是诱导 aCL 形成、改善黄体组织生物测定和 P4 浓度以及增加出生羔羊总数的有效治疗方法。