Borchardt Stefan, Pohl Alina, Heuwieser Wolfgang
Clinic for Animal Reproduction, Faculty of Veterinary Medicine, Freie Universität Berlin, Koenigsweg 65, 14163 Berlin, Germany.
Animals (Basel). 2020 Sep 2;10(9):1551. doi: 10.3390/ani10091551.
Progesterone (P4) concentration during follicular growth has a major impact on fertility response in timed artificial insemination (TAI) protocols. Luteal presence at the beginning of a TAI protocol and ovarian response after the first gonadotropin-releasing hormone (GnRH) injection (G1) affect P4 concentration and subsequently pregnancy per artificial insemination (P/AI). A systematic review of the literature and meta-analytical assessment was performed with the objective of evaluating the magnitude of the effect of luteal presence and ovarian response at the beginning of a TAI protocol on P/AI in lactating dairy cows. We considered only studies using synchronisation protocols consisting of GnRH and prostaglandin F . The time interval between G1 and prostaglandin F (PGF ) had to range from 5 to 7 d. The time interval between the PGF injection and G2 had to range from 48 to 72 h. We used 28 controlled experiments from 27 published manuscripts including 16,489 cows with the objective of evaluating the effect size of having a functional corpus luteum (CL) at G1 on P/AI. Information regarding ovulatory response after G1 was available for 5676 cows. In a subset of cows ( = 4291), information was available for luteal presence and ovulatory response at the initiation of the TAI protocol. A functional CL at G1 increased ( < 0.001) the relative risk of conceiving (RR (relative risk) = 1.32; 95% CI = 1.21-1.45) in lactating dairy cows. Ovulation after G1 increased ( < 0.001) the relative risk of conceiving (RR = 1.29; 95% CI = 1.20-1.38) in lactating dairy cows. The effect of ovulatory response on P/AI after G1 was affected by luteal presence at G1. In summary, there was a clear benefit on P/AI for cows starting a TAI protocol with a functional CL (+10.5 percentage units) and cows ovulating at the beginning of a TAI protocol (+11.0 percentage units).
在定时人工授精（TAI）方案中，卵泡生长期间的孕酮（P4）浓度对繁殖力反应有重大影响。TAI方案开始时黄体的存在以及首次促性腺激素释放激素（GnRH）注射（G1）后的卵巢反应会影响P4浓度，进而影响每人工授精的妊娠率（P/AI）。进行了一项文献系统综述和荟萃分析评估，目的是评估TAI方案开始时黄体的存在和卵巢反应对泌乳奶牛P/AI的影响程度。我们仅考虑使用由GnRH和前列腺素F组成的同步方案的研究。G1与前列腺素F（PGF）之间的时间间隔必须在5至7天之间。PGF注射与G2之间的时间间隔必须在48至72小时之间。我们使用了来自27篇已发表手稿的28项对照实验，涉及16489头奶牛，目的是评估G1时具有功能性黄体（CL）对P/AI的效应大小。有5676头奶牛可获得G1后排卵反应的信息。在一部分奶牛（n = 4291）中，可获得TAI方案开始时黄体存在和排卵反应的信息。G1时功能性CL增加了（P < 0.001）泌乳奶牛受孕的相对风险（RR（相对风险）= 1.32；95% CI = 1.21 - 1.45）。G1后排卵增加了（P < 0.001）泌乳奶牛受孕的相对风险（RR = 1.29；95% CI = 1.20 - 1.38）。G1后排卵反应对P/AI的影响受G1时黄体存在的影响。总之，对于开始TAI方案时具有功能性CL的奶牛（增加10.5个百分点）和在TAI方案开始时排卵的奶牛（增加11.0个百分点），P/AI有明显益处。
