Eissa H M, Nachreiner R F, Refsal K R
Endocrine Diagnostic Section, Michigan State University, E. Lansing 48823.
Vet Res Commun. 1994;18(2):149-54. doi: 10.1007/BF01839234.
The skim milk progesterone profile was assessed by radioimmunoassay, without extraction, from the day of insemination (day 0) until the cows were dried off on day 225 of gestation. A total of 418 samples were collected from 154 pregnant Holstein cows. The daily variation in skim milk progesterone was recorded from day 1 until day 45 of pregnancy to detect the commencement of progesterone secretion from the corpus luteum after insemination. Subsequent determinations were made every 2 weeks from day 46 until lactation ceased. On the day of artificial insemination and for the first 2 days after insemination, all the cows had a basal progesterone concentration < 0.1 ng/ml. A rise in progesterone (0.2 +/- 0.1 ng/ml) was first detected on the third day after insemination. The progesterone values then increased significantly (p < 0.001) until day 15. The values then remained nearly constant (2.5-3.5 ng/ml) until day 106 of pregnancy, when they began to decline. Between days 120 and 180 of gestation, progesterone was significantly decreased (2.2-2.9 ng/ml) before it rose again to the previous plateau (3.5-3.9 ng/ml) around day 180. The progesterone concentration then remained at the higher level until the animals were dried off.
采用放射免疫分析法，在不进行提取的情况下，从授精当天（第0天）开始，直至妊娠第225天奶牛干奶，对脱脂乳中的孕酮水平进行评估。共从154头怀孕的荷斯坦奶牛身上采集了418份样本。记录妊娠第1天至第45天脱脂乳中孕酮的每日变化情况，以检测授精后黄体开始分泌孕酮的时间。从第46天到泌乳停止，每2周进行一次后续测定。在人工授精当天及授精后的头2天，所有奶牛的基础孕酮浓度均<0.1 ng/ml。授精后第三天首次检测到孕酮升高（0.2±0.1 ng/ml）。随后孕酮值显著升高（p<0.001），直至第15天。此后，孕酮值在妊娠第106天之前基本保持恒定（2.5 - 3.5 ng/ml），之后开始下降。在妊娠第120天至第180天期间，孕酮显著下降（2.2 - 2.9 ng/ml），然后在第180天左右再次升至先前的平台期（3.5 - 3.9 ng/ml）。此后，孕酮浓度一直保持在较高水平，直至奶牛干奶。
