奶牛产后卵巢活动恢复迟早与繁殖率关系分析

AN ANALYSIS OF THE RELATIONSHIP BETWEEN THE LENGTH OF RESUMPTION OF OVARIAN ACTIVITY IN THE POSTPARTUM PERIOD AND FERTILITY OF DAIRY COWS

应用通讯奶样放射免疫分析测定奶中孕酮含量，确定了１６４头奶牛产后卵巢活动恢复时间。恢复时间在产后３０ｄ内的有６４头；在产后３０ｄ至６０ｄ之间的有５０头；在产后６０ｄ至８５ｄ之间的有５头；在产后８５ｄ以上才恢复的有３头。第一、第二及第三次排卵的隐性发情率分别为８１．２％、４３．９％和１６．０％。要使奶牛产后８５ｄ内配种怀孕，保证一年一胎，卵巢活动和子宫的早期恢复是必须的。卵巢活动恢复延迟使空怀期延长（ｒ＝０．８２６９）。产后卵巢活动恢复正常（≤５０天）的牛具有高的情期受胎率（Ｘ＝６０．９％）、总受胎率（Ｘ＝９２．９％）和较短的空怀期。产后卵巢活动恢复延迟（＞５０ｄ）的牛情期受胎率和总受胎率均较低，分别为３２．３％和７５．４％。

オhe initiating days of resumption of ovarian activity in 164 postpartum dairy cows determined by progesterone measurements using radioimmunoassay in communication milk samples were no more than 30 days(64 cows),between 30 to 60 days (50 cows),between 60 to 85 days(5cows),and more than 85 days (3 cows).The silent estrus rates of the first,second and third ovulation in postpartum cows were 81.2%,43.9% and 16.0% respectively.Early resumption of ovarian activity and uterine involution in postpartum cows is required for service and conception of cows within 85 days after parturition,which are necessary targets if a 365 days calving interval is to be attained.The delay of resumption of ovarian activity prolonged barren period and the related coefficient between them were 0.8269.Cows with normal resumption of ovarian activity that was no more than 50 days postpartum had high conception rates after first insemination(x=60.9%),total conception rates(x=92.9%) and short barren period.The delay of resumption that was more than 50 days post partum decreased conception rates after first insemination(x=32.3%) and total conception rates (x=75.4%).