中国荷斯坦牛发情周期中孕酮、雌二醇含量的变化规律

Change of Contents of Progesterone and Oestradiol in the Milk of Chinese Holstein Cow During Oestrous Cycle

应用放射免疫分析方法测定了50头中国荷斯坦牛产后90d乳中孕酮、雌二醇的含量,累计采集乳样1642个。结果表明:发情周期中孕酮变化特征可用参数来描述,①孕酮的最高水平(2.08ng·mL-1);②孕酮含量上升期的持续时间约15d;③孕酮含量维持在高峰期的时间约3d;④孕酮含量下降的速度为0.54ng·d-1。而雌二醇在发情时达到高峰,其峰值是69pg。发情前后雌二醇水平在40pg左右,波动较小。产后孕酮及雌二醇含量均迅速下降。孕酮在产后1d下降至较低水平,直到产后17d又开始上升,说明有些牛此时卵巢已开始活动。雌二醇在产后2d下降至较低水平,直至产后23d一直维持在较低水平波动。

The Contents of progesterone and oestradiol in the milk of 50 Chi ne se Holstein Cows(1 642 milk samples in total) were measured during a period of 9 0 days after calving by radioimmunoassay. The result indicated that the characte ristics for the change of the content of progesterone in the milk could be descr ibed with the following parameters: the highest level of progesterone reached 2. 08 ng· mL- 1; the duration of increasing progesterone lasted for about 15 days ; the content of progesterone decreased at the rate of 0.54 ng· d- 1; while th e content of oestradiol reached its peak during oestrous cycle with a peak value of 69 pg· mL- 1 .The level of oestradiol of pre- heat and post- heat period s remained at 40 pg· mL- 1 or so with a rather weak fluctuation. The content o f oestradiol reduced rapidly after delivery. During the first day after delivery it reduced to very low level till it started to rise again in the 17th day afte r delivery, and this showed that the ovary of cows became active again. The cont ent of oestradiol reduced to a rather low level in the 2nd day after delivery an d fluctuated at a very low level till the 23rd day.