This study compares the fertility effects of inducing ovulation using the GnRH analogue dephereline versus natural GnRH at the end of a 5-day progesterone(P4)-based protocol for fixed-time artificial insemination (FTAI) in heat-stressed and non-heat stressed anestrous lactating dairy cows. Cows were given GnRH (GnRH group, n = 676) or dephereline (DEPH group, n = 655) and inseminated 12 hours later. Based on odds ratios, pregnancy loss was 3.6 times more likely in cows carrying twins (P < 0.0001) and 0.4 times less likely in DEPH treated cows (P = 0.0005). No significant effects of treatment on the pregnancy rate were identified by binary logistic regression and the variables examined did not influence the twin pregnancy rate. In conclusion, compared to treatment with GnRH, dephereline given at the end of a 5-day P4-based protocol for FTAI reduced the risk of pregnancy loss regardless of the presence or absence of heat stress.

这项研究比较了在热应激和非热应激的固定时间人工授精（FTAI）的基于5天孕酮（P4）的基于5天孕激素（P4）的方案结束时使用GnRH类似物去卵灵与天然GnRH诱导排卵的生育力影响发情的泌乳奶牛。母牛接受GnRH（GnRH组，n = 676）或磷灵（DEPH组，n = 655），并在12小时后授精。根据比值比，携带双胞胎的母牛的妊娠损失可能性高3.6倍（P <0.0001），经DEPH处理的母牛的妊娠损失可能性低0.4倍（P = 0.0005）。二元逻辑回归分析未发现治疗对妊娠率的显着影响，所检查的变量未影响双胎妊娠率。总之，与GnRH治疗相比，