Objectives were to evaluate effects of a smaller than typically used dose of equine chorionic gonadotropin (eCG) during a fixed-time artificial insemination (FTAI) treatment regimen. Transrectal ultrasonic (US) examinations were conducted on dairy cows on Day 0 (D0) and the treatment regimen was initiated with administrations of an intravaginal progesterone (P₄) implant, estradiol benzoate (im), and prostaglandin F_2α (PGF_2α; im). On D8, the P₄ implant was removed and PGF_2α and estradiol cypionate were administered to all animals. Subsequently, cows were randomly assigned to three groups and eCG was administered to Groups 1, 2, and 3 in doses of 300 (im); 100 (im); and 100 (Baihui acupoint) IUs, respectively. The B-mode and power-flow US cineloops were performed to assess follicular dynamics and evaluate various morphological and vascular characteristics of the corpus luteum. Blood samples were collected to quantify serum P₄ concentrations. There were no differences between the ovulation synchronization treatment regimens for all follicular dynamic variables tested; however, cows in Group 3 differed from Group 2 having a larger follicle diameter (FD) on D10 (P = 0.06) and larger preovulatory FD (P = 0.09), as well as a blood perfusion area of the dominant follicle wall on D8 (P = 0.07). There were no differences in responses to the ovulation synchronization treatment regimens for the luteal variables evaluated subsequent to ovulation. In conclusion, the Baihui acupoint was effective as an alternative route for eCG dose reduction when FTAI treatment regimens were imposed without detrimentally affecting values for reproductive variables.

目的是在固定时间人工授精 (FTAI) 治疗方案中评估比通常使用的马绒毛膜促性腺激素 (eCG) 剂量更小的效果。在第 0 天 (D0) 对奶牛进行经直肠超声 (US) 检查，治疗方案开始于给予阴道内孕酮 (P ₄ ) 植入物、苯甲酸雌二醇 (im) 和前列腺素 F _2α (PGF _2α； im ）。在第_{8 天}，移除P ₄植入物并对所有动物施用PGF _2α和环戊丙酸雌二醇。随后，奶牛被随机分配到三组，eCG 以 300 (im) 的剂量分配给第 1、2 和 3 组；100 (im); 和100（百惠穴位) IUs，分别。执行 B 模式和功率流 US cineloops 以评估卵泡动力学并评估黄体的各种形态和血管特征。收集血样以量化血清P ₄浓度。对于所有测试的卵泡动态变量，排卵同步治疗方案之间没有差异；然而，第 3 组奶牛与第 2 组不同，第 10 天的卵泡直径 (FD) 较大 ( P = 0.06) 和排卵前 FD 较大 ( P = 0.09)，以及第 8 天优势卵泡壁的血液灌注区域（磷= 0.07）。对于排卵后评估的黄体变量，对排卵同步治疗方案的反应没有差异。总之，当实施 FTAI 治疗方案时，百会穴可有效减少 eCG 剂量，而不会对生殖变量的值产生不利影响。