奶牛产犊胎次与乳中孕酮、雌二醇含量的关系

Relationship Between the Parity of Chinese Holstein Cows and the Contents of Progesterone and Oestradiol in Their Milk

用放射免疫法测定了50头中国荷斯坦牛产后23d内及发情前后12d内乳中的孕酮(P)和雌二醇(E2)的含量。结果表明:产后23d内不同胎次的奶牛孕酮,雌二醇含量差异不显著,而产后不同天数之间的孕酮、雌二醇含量差异极显著(P<0.01)。不同胎次间发情前后12d内的孕酮、雌二醇含量差异不显著(P>0.05),而发情不同天数之间的孕酮、雌二醇含量差异极显著(P<0.01)。

The Contents of progesterone and oestradiol in the milk of 50 Chinese Holstein cows were measured within a period of 23 days after calving and a period of 12 days around estrus using radioimmunoassay. The result indicated that the contents of progesterone and oestradiol in the milk of Holstein cows in different parity were not significant, while the contents of progesterone and that of oestradiol in different days alter postpartum were highly significantly different （P〈0.01）. Within a period of 12 days around estrus the difference between the content of progesterone and that of oestradiol in different parity was not significant, whereas the difference of the content of progesterone and that of oestradiol at different days of the estrus was highly significant（P〈0.01）.