Meisterling E M, Dailey R A
Division of Animal and Veterinary Sciences, West Virginia University, Morgantown 26506-6108.
J Dairy Sci. 1987 Oct;70(10):2154-61. doi: 10.3168/jds.S0022-0302(87)80268-0.
Data from artificial insemination, rectal palpation, and hormone assays were used to characterize postpartum reproductive activity in 54 dairy cows. Progesterone and estradiol-17 beta were measured in milk samples collected for 120 d (Trial 1) or 65 d (Trial 2). Progesterone was higher and estradiol was lower in milk than in serum. Values for both hormones in milk were highly correlated with those in serum. Most cows (64%) had short first luteal phases (less than or equal to 12 d). First rise (28 d) in progesterone was later (33.4 vs. 24.9 d) for cows having short rather than normal (greater than 12 d) luteal phases. Cows were classified as having a short luteal phase followed by a normal luteal phase or as having normal luteal phases for the first two estrous cycles. Estradiol for the 6 d prior to each luteal phase was higher preceding the second phase than the short phase or those preceding both phases of cows with normal phases. Follicular function prior to ovulation, as measured by estradiol, was not responsible for short-lived corpora lutea. Concentrations of progesterone in milk in the late luteal phase prior to insemination were related to fertility.
利用人工授精、直肠触诊和激素检测的数据，对54头奶牛产后的生殖活动进行了表征。在为期120天（试验1）或65天（试验2）收集的牛奶样本中测量孕酮和雌二醇-17β。牛奶中的孕酮含量高于血清，而雌二醇含量低于血清。牛奶中这两种激素的值与血清中的高度相关。大多数奶牛（64%）的第一个黄体期较短（小于或等于12天）。黄体期短的奶牛孕酮首次升高（28天）的时间比黄体期正常（大于12天）的奶牛晚（33.4天对24.9天）。奶牛被分类为第一个黄体期短随后黄体期正常，或者在前两个发情周期中黄体期均正常。每个黄体期前6天的雌二醇，第二个黄体期之前高于短黄体期或正常黄体期奶牛两个黄体期之前的水平。通过雌二醇测量的排卵前卵泡功能与黄体寿命短无关。授精前黄体后期牛奶中的孕酮浓度与繁殖力有关。
