We examined the effect of human chorionic gonadotropin (hCG) treatment 5 days after estrus on ovarian dynamics and plasma progesterone (P4) and estradiol (E2) concentrations when the first-wave dominant follicle (DF) was ipsilateral or contralateral to the corpus luteum (CL) in lactating dairy cows. Seventy cows were divided into two groups: (1) ipsilateral group (IG; n = 37), in which the first-wave DF was ipsilateral to the CL, and (2) contralateral group (CG; n = 33), in which the first-wave DF was contralateral to the CL. IG and CG were further subdivided into two groups: non-treatment group (IG, n = 18; CG, n = 19), and hCG treatment group: administrated 1500 IU of hCG 5 days after estrus (IG, n = 19; CG, n = 14). Blood sampling and ovarian examination were performed at 3, 5, 7, 9, 11, and 13 days after estrus. Mean diameter of the first-wave DF on Day 9 tended (P = 0.067) to be larger in IG than in CG in the non-treatment group. Mean diameter of CL and plasma P4 and E2 concentrations did not differ between IG and CG in the non-treatment and hCG treatment groups. Accessory CL development did not differ between IG and CG in the hCG treatment group. Our findings indicate that CL development and plasma P4 and E2 concentrations were not affected by the existence of the first-wave DF; however, first-wave DF development was affected by the existence of a CL in the same ovary.

中文翻译：

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同侧第一波优势卵泡和黄体共存对人绒毛膜促性腺激素治疗泌乳奶牛卵巢动力学和血浆性类固醇激素浓度的影响

当第一波优势卵泡 (DF) 与黄体同侧或对侧时，我们检查了发情后 5 天人绒毛膜促性腺激素 (hCG) 治疗对卵巢动力学和血浆孕酮 (P4) 和雌二醇 (E2) 浓度的影响。 CL) 在泌乳奶牛中。70 头奶牛被分为两组：（1）同侧组（IG；n = 37），其中第一波 DF 位于 CL 的同侧；（2）对侧组（CG；n = 33），其中第一波 DF 位于 CL 的对侧。IG和CG进一步细分为两组：非治疗组（IG，n=18；CG，n=19），hCG治疗组：发情后5天给予1500IU的hCG（IG，n=19；CG , n = 14)。在发情后3、5、7、9、11和13天进行采血和卵巢检查。在第 9 天，IG 中第一波 DF 的平均直径倾向于（P = 0.067）大于非治疗组中的 CG。CL 的平均直径和血浆 P4 和 E2 浓度在非治疗组和 hCG 治疗组中 IG 和 CG 之间没有差异。在 hCG 治疗组中，IG 和 CG 之间的辅助 CL 发展没有差异。我们的研究结果表明，CL 发展和血浆 P4 和 E2 浓度不受第一波 DF 的影响；然而，第一波 DF 的发展受到同一卵巢中 CL 的影响。在 hCG 治疗组中，IG 和 CG 之间的辅助 CL 发展没有差异。我们的研究结果表明，CL 发展和血浆 P4 和 E2 浓度不受第一波 DF 的影响；然而，第一波 DF 的发展受到同一卵巢中 CL 的影响。在 hCG 治疗组中，IG 和 CG 之间的辅助 CL 发展没有差异。我们的研究结果表明，CL 发展和血浆 P4 和 E2 浓度不受第一波 DF 的影响；然而，第一波 DF 的发展受到同一卵巢中 CL 的影响。