This study evaluated the association between plasma anti‐Mullerian hormone (AMH) concentration and fertility in Nelore (Bos indicus ) heifers submitted to timed artificial insemination (TAI). At the onset of the synchronization protocol, heifers (n  = 289) received a subcutaneous P4 ear implant (3 mg) and 2 mg of oestradiol benzoate. Eight days later, the P4 implant was removed and 0.5 mg of oestradiol cypionate, prostaglandin (0.265 mg, i.m.) and equine chorionic gonadotropin (300 UI, i.m.) was administered, and TAI was performed 48 hr after ear implant removal. Ovarian ultrasound evaluations were performed to measure number of ovarian follicles, dominant follicle size and ovulation response. Pregnancy diagnosis was performed by ultrasound 30 days after AI. Heifers with greater circulating AMH had more antral follicles, a smaller dominant follicle near timed ovulation and lower ovulation response to the timed AI protocol compared to heifers with lower circulating AMH. Although AMH and pregnancy outcome had a quadratic‐shaped pattern, AMH was not significantly associated with fertility. In conclusion, heifers with lower AMH had larger follicles towards the end of the synchronization protocol and greater ovulation responses, whereas greater circulating AMH was unrelated to conception success.

中文翻译：

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定时AI Bos indicus小母牛的抗Mullerian激素及其与排卵反应和生育力的关系。

这项研究评估了定时人工授精（TAI）的内罗尔（Bos indicus）母牛的血浆抗穆勒氏激素（AMH）浓度与生育能力之间的关系。在同步协议开始时，小母牛（n = 289）接受皮下P4耳植入物（3 mg）和2 mg雌二醇苯甲酸酯。八天后，取下P4植入物，并给予0.5 mg的雌二醇cypionate，前列腺素（0.265 mg，im）和马绒毛膜促性腺激素（300 UI，im），并在摘除耳朵植入物48小时后进行TAI。进行卵巢超声评估以测量卵巢卵泡数目，优势卵泡大小和排卵反应。AI 30天后通过超声进行妊娠诊断。与循环AMH较低的母牛相比，循环AMH较高的母牛具有更多的窦性卵泡，接近排卵的优势卵泡较小，并且对定时AI方案的排卵反应较低。尽管AMH和妊娠结局呈二次方型，但AMH与生育率没有显着相关。