Villarroel Aurora, Martino Alex, BonDurant Robert H, Dèletang François, Sischo William M
School of Veterinary Medicine, University of California, One Garrod Ave, Davis, CA 95616, USA.
Theriogenology. 2004 May;61(7-8):1513-20. doi: 10.1016/j.theriogenology.2003.09.001.
Embryonic mortality contributes to repeat-breeding in dairy cows; luteal insufficiency is a known cause of embryonic mortality. The objective of this study was to assess the efficacy of supplementation with exogenous progesterone for 14 days on pregnancy maintenance in inseminated repeat-breeder dairy cows. On Day 5 after insemination, treated cows ( n=143 ) received a modified PRID (i.e. without estradiol capsule), which was removed on Day 19. Control cows ( n=148 ) did not receive any treatment. Overall there was no effect of PRID supplementation on pregnancy rates. However, when the study population was stratified by parity and stage of lactation, PRID supplementation significantly improved pregnancy rate in first and second parity late lactation cows (risk ratio = 3.26; 95% CI 1.22, 8.69). Pregnancy rates did not differ between PRID-treated cows with ( n=81 ) and without vaginitis. Control cows tended ( P=0.077 ) to have a higher proportion of abortions than PRID-treated cows (7/50 versus 2/51, respectively). In conclusion, young late lactation repeat-breeder cows benefited from progesterone supplementation, in terms of maintaining pregnancy until traditional time of pregnancy diagnosis.
胚胎死亡是导致奶牛屡配不孕的原因之一；黄体功能不全是已知的胚胎死亡原因。本研究的目的是评估对授精后的屡配不孕奶牛补充外源性孕酮14天对维持妊娠的效果。在授精后第5天，接受治疗的奶牛（n = 143）植入改良型孕酮释放阴道装置（即不含雌二醇胶囊），并于第19天取出。对照奶牛（n = 148）未接受任何治疗。总体而言，补充孕酮释放阴道装置对妊娠率没有影响。然而，当按胎次和泌乳阶段对研究群体进行分层时，补充孕酮释放阴道装置显著提高了头胎和二胎泌乳后期奶牛的妊娠率（风险比 = 3.26；95%置信区间1.22, 8.69）。有阴道炎和无阴道炎的接受孕酮释放阴道装置治疗的奶牛之间妊娠率没有差异。对照奶牛的流产比例往往（P = 0.077）高于接受孕酮释放阴道装置治疗的奶牛（分别为7/50和2/51）。总之，就维持妊娠至传统妊娠诊断时间而言，年轻的泌乳后期屡配不孕奶牛从补充孕酮中获益。
