Department of Animal Sciences and Industry, Kansas State University, Manhattan, Kansas, USA.
Theriogenology. 2010 May;73(8):1127-38. doi: 10.1016/j.theriogenology.2010.01.014. Epub 2010 Jan 22.
Our objective was to determine whether rates of luteolysis or pregnancy differed in lactating dairy cows of known progesterone status and either known or unknown luteal status after either cloprostenol or dinoprost was injected as part of a timed-insemination program. In Experiment 1, 2358 lactating dairy cows in six herds were given two injections of PGF(2 alpha) 14 d apart (Presynch), with the second injection given 12 to 14 d before the onset of a timed AI protocol (Ovsynch). Cows (n=1094) were inseminated when detected in estrus after the Presynch PGF(2 alpha) injections. Cows not inseminated (n=1264) were enrolled in the Ovsynch protocol and assigned randomly to be treated with either cloprostenol or dinoprost as part of the timed-AI protocol. In cows having pretreatment concentrations of progesterone >or= 1 ng/mL and potentially having a functional corpus luteum (CL) responsive to cloprostenol (n=558) or dinoprost (n=519), dinoprost increased (P<0.05) luteal regression from 86.6 to 91.3%. Despite a significant increase in luteolysis, pregnancies per AI did not differ between luteolytic agents (dinoprost=37.8% and cloprostenol=36.7%). Fertility was improved in cows of both treatments having reduced concentrations of progesterone at 72 h and in cows showing signs of estrus. In Experiment 2, an ovulation-resynchronization program was initiated with GnRH or saline in 427 previously inseminated lactating dairy cows of unknown pregnancy status in one herd. Seven days later, pregnancy was diagnosed and nonpregnant cows were blocked by number of CL and assigned randomly to be treated with cloprostenol or dinoprost. Compared with cloprostenol, dinoprost increased (P<0.05) luteal regression from 69.1 to 78.5%, regardless of the number of CL present or the total luteal volume per cow. Pregnancies per AI did not differ between dinoprost (32.8%) and cloprostenol (31.3%). Although dinoprost was more effective than cloprostenol at inducing luteolysis in lactating dairy cows exposed to an Ovsynch or ovulation-resynchronization protocol, resulting fertility did not differ between products.
我们的目的是确定在已知孕激素状态且黄体状态已知或未知的泌乳奶牛中，在进行定时人工授精程序时分别注射氯前列醇或地诺前列酮后，黄体溶解或妊娠的发生率是否存在差异。在实验 1 中，6 个牛群的 2358 头泌乳奶牛接受了两次 PGF(2 alpha)注射，两次注射间隔 14 天，第二次注射在定时人工授精方案（Ovsynch）开始前 12-14 天进行。在两次 PGF(2 alpha)注射后发情的奶牛（n=1094）进行授精。未授精的奶牛（n=1264）被纳入 Ovsynch 方案，并随机分为氯前列醇或地诺前列酮组，作为定时人工授精方案的一部分。在预处理时孕激素浓度>或=1ng/ml 且可能存在对氯前列醇（n=558）或地诺前列酮（n=519）有反应的功能性黄体（CL）的奶牛中，地诺前列酮增加（P<0.05）黄体溶解率从 86.6%到 91.3%。尽管黄体溶解显著增加，但两种黄体溶解剂（地诺前列酮=37.8%和氯前列醇=36.7%）之间的妊娠率没有差异。在 72 小时孕激素浓度降低和出现发情迹象的两种处理的奶牛中，妊娠率得到改善。在实验 2 中，在一个牛群中，427 头先前已授精的泌乳奶牛的妊娠状况未知，用 GnRH 或生理盐水启动排卵同步化方案。7 天后，进行妊娠诊断，根据黄体数和总黄体体积将未妊娠奶牛分为 BLOCK，并随机分为氯前列醇或地诺前列酮组。与氯前列醇相比，地诺前列酮增加（P<0.05）黄体溶解率从 69.1%到 78.5%，与黄体数或每头牛的黄体总体积无关。地诺前列酮（32.8%）和氯前列醇（31.3%）的妊娠率没有差异。尽管地诺前列酮在接受 Ovsynch 或排卵同步化方案的泌乳奶牛中诱导黄体溶解的效果优于氯前列醇，但两种产品的产犊率没有差异。
