PDF(Pubmed)
Abstract：
This study investigated the effects of timed artificial insemination (TAI) and equine chorionic gonadotropin (eCG) administration on lactating dairy cows under heat-stress conditions (average temperature-humidity index: 80). Timed artificial insemination was performed on the cows with (n = 57) or without (control, n = 41) supplementation with 500 IU of eCG at the day of PGF2α treatment using the CIDR-Ovsynch protocol. GnRH was administered, and a progesterone device (CIDR) was inserted on Day -10 of the treatment protocol. The CIDR was removed on Day -3, and the cows were treated with PGF2α. Two days later, a 2nd GnRH injection was administered. Subsequently, AI was performed on Day 0 (16-20 h after the 2nd GnRH injection), and pregnancy was diagnosed on Days 32 and 60. Plasma progesterone (P4) concentrations were measured after AI. Results showed that the eCG group had a higher pregnancy per AI (P/AI) than the control group (43.9 vs. 12.2%, P = 0.002), which was also accompanied by elevated P4 levels. Four cows in the eCG group had multiple calves, representing 7.0 and 16.0% of the group and pregnant cows, respectively. In conclusion, 500 IU of eCG combined with CIDR-Ovsynch in lactating dairy cows under severe heat stress conditions successfully improved fertility. However, the protocol may have a slight risk of multiple births.
摘要：
这项研究调查了在热应激条件下（平均温度-湿度指数：80），定时人工授精（TAI）和马绒毛膜促性腺激素（eCG）给药对泌乳奶牛的影响。对有(n=57)或没有(对照，n=41）在PGF2α治疗当天使用CIDR-Ovsynch方案补充500IU的eCG。给予GnRH,并在治疗方案的第-10天插入孕酮装置(CIDR)。在第-3天除去TheCIDR,用PGF2α处理母牛。两天后,给予第二次GnRH注射。随后，AI在第0天（第二次GnRH注射后16-20小时）进行，在第32天和第60天被诊断出怀孕。AI后测量血浆孕酮（P4）浓度。结果显示，eCG组的每个AI（P/AI）的妊娠率高于对照组（43.9vs.12.2%,P=0.002),这也伴随着升高的P4水平。eCG组中的四头母牛有多个小牛，占该组和怀孕母牛的7.0%和16.0%，分别。总之,在严重的热应激条件下，在泌乳奶牛中使用500IU的eCG与CIDR-Ovsynch相结合，成功地提高了生育能力。然而,该方案可能有轻微的多胎风险.
