鲁西黄牛发情周期和产后期外周血浆孕酮水平

Changes of Progesterone Levels in Peripheral Blood during Oestrous Cycles and Postpartum Periods in Luxi Yellow Cows

在鲁西黄牛母牛的发情周期和产后期（产犊至产后６０ｄ）收集颈静脉血样，用放射免疫分析法测定血浆孕酮（Ｐ４）水平。结果表明，母牛的发情周期平均为（２１．２±１．６）ｄ，发情当天（０ｄ）外周血浆孕酮水平为（０．５２±１．４）μｇ／Ｌ，在周期的９～１５ｄ，孕酮水平较高，其峰值为（４．６２±１．５６）μｇ／Ｌ（ｎ＝１５），在周期的约１８ｄ以后，孕酮水平迅速下降，至周期的２１ｄ降至发情开始时的水平；母牛产后１０．６～１３．６ｄ以后，外周血浆孕酮水平开始升高，出现黄体周期，约有一半的母牛产后第１个黄体周期为（８．４±０．５）ｄ，显著短于正常周期（２０．１±３．２）ｄ（Ｐ＜０．０１）；在短周期中，孕酮峰值为（１．５２±０．７１）μｇ／Ｌ，亦显著低于正常周期孕酮峰值（３．８４±１．２５）μｇ／Ｌ（Ｐ＜０．０５）。除短周期外。

The blood samples were collected from jugular veins of Luxi cows during oestrous cycles and postpartum periods, and progesterone(P 4) levels in the blood plasma were determined by radioimmunoassay (RIA). The results were summarized as follows: In cycling cows, the oestrous cycle averaged 21.2±1.6 days, the P 4 levels in plasma were (0.52±1.4)μg/L on the day of oestrous (0 day), then began to rise and reached high level with (4.62±1.56)μg/L of peak in 9 15 days of cycle, and reduced to the level in oestrous in 18 21 days of cycle. In postpartum cows, P 4 levels in plasma began to rise and showed luteal cycles in 10.6 13.6 days postpartum. But the first luteal cycles postpartum were significantly shorter than normal ones ( P <0.01) in almost half of cows (7/15), and P 4 peak in short luteal cycles was significantly belower than that in normal ones ( P <0.05). Except in short cycles, the changes of P 4 levels in blood plasma of postpartum cows showing luteal cycles were similar to that of cycling cows.