ABSTRACT The objective of the present study was to evaluate the administration of Equine Chorionic Gonadotropin (eCG) in a protocol of fixed-time artificial insemination (FTAI) to increase the pregnancy rate in cows subjected to high altitude conditions. These conditions could generate a syndrome of right-sided heart failure and, as consequence, animals trend to have a low body score condition with a decrease in fertility. The research was conducted with 84 lactating cows (Brown Swiss) randomly into two groups with a body condition score between 2.5 and 3.5, allocated at 3100 m above sea level. In the FTAI protocol, 400 IU of eCG was administered (n = 42) or not (n = 42) at progesterone intravaginal device removal. A significant improvement in pregnancy rate was found with eCG treatment in those cows with low body condition score (BCS of 2.5, scale 1–5), while no effect was found in those cows with higher BCS (i.e. 3.0 and 3.5). In conclusion, the addition of 400 IU of eCG in an FTAI in cows under high altitude conditions and low body conditions can improve the fertility.

中文翻译：

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高海拔条件下马绒毛膜促性腺激素对棕色瑞士奶牛妊娠率的影响

摘要 本研究的目的是评估在固定时间人工授精 (FTAI) 方案中使用马绒毛膜促性腺激素 (eCG) 以提高受高海拔条件影响的奶牛的妊娠率。这些情况可能会产生右侧心力衰竭的综合征，因此，动物往往会出现身体评分较低且生育能力下降的情况。该研究将 84 头泌乳奶牛（Brown Swiss）随机分为两组，身体状况评分介于 2.5 和 3.5 之间，分布在海拔 3100 m 处。在 FTAI 协议中，在移除黄体酮阴道装置时，给予 (n = 42) 或不给予 (n = 42) 400 IU 的 eCG。在那些身体状况评分较低（BCS 为 2.5，等级 1-5），而在那些具有较高 BCS（即 3.0 和 3.5）的奶牛中没有发现影响。综上所述，在高海拔和低体况条件下的奶牛FTAI中添加400 IU的eCG可以提高生育能力。