牦牛发情周期血浆中LH、P_4、17β-E_2的变化规律及其与卵巢功能的关系

The Regularity of variations of Luteinizing Hormone (LH), progesterone (P_4) and Oestradiol-17β(17β-E_2)in the Peripheral Plasma from Chinese Yaks During a Estrous Cycle and the Relationship Between These Regularity and Ovarian Function

选择13头5—7岁的健康母牦牛做试验牛,用成年阉牦牛做试情牛,结合直肠检查卵泡发育情况。从发情之日起,每天一次(发情期每天两次)用真空采血管从颈静脉采血2.0ml,离心分离血浆。血浆用液氮滴冻成颗粒,保存于液氮罐中。血浆LH、P4、17β-E_2含量用放射免疫分析法测定。结果表明,牦牛发情周期血浆P4水平在发情期较低,平均0.1785±0.0928ng/ml;黄体期较高,平均5.1824±0.3475ng/ml。17β-E_2在发情盛期上升到峰值,平均27.2918±2.1057Pg/ml,发情结束后降至基础水平,黄体期,在第4和9天时分别出现一峰值,到第16天时又上升到发情盛期水平。LH在发情初期较低,友情盛期上升到峰值,平均17 1824±2 1174ng/ml,发情结束后降至基础水平,黄体期在1～3ng/ml间波动。本文根据牦牛发情周期血浆LH、P4、17β-E_2的变化特点,结合直肠检查结果,探讨了牦牛发情周期血浆LH、P4、17β-E_2的变化规律及其与卵巢功能的关系。认为:母牦牛的发情应以静立接受试情牛爬跨为指征,牦牛的排卵发生在LH峰后约24小时内,即在母牦牛静立接受试情牛爬跨后24小时内。

Thirteen female yaks aged 5 to 7 day were selected from Longri Breeding Stock Farm in Sichuan province, and blood sample (20ml) from each of these yaks was obtained via jugular vein every day from the first day of oestrus to the end of estrous cycle. The plasma was separated by centrifugation and stored in liquid nitrogen container for the determination of the leves of luteinzing hormone (LH), 17β-oestradiol(17β-E_2) and progesterone (P_4) by radioimmunoassay. The estrous signs and the development of ovarian follicle were checked by two vasectomized teasers or by rectal palpation. The P_4 level was lower (0.1785±0.0928ng/ml) during the oestrum, but it began to rise after ovulation and maintained a high value(5.1824±0.3418ng/ml) at the luteal phase, and than it fell to the lowest level after 16th day of the estrous begining. The average plasma 17β-E_2 value was lower (5.1829±0.5822 pg/ml) at the onset of estrus and it reached the peak value (27.2918±2.0157pg/ml) at the exuberant time of the estrus, at this moment the female yak standed quietly and allowed the teaser mounting, than it appeared two slight peak value on 4th and 9th day after the onset of estrus, respectively. The LH level began to rise after the begining of estrus and appeared a peak value (17.1824±0.1174ng/ml) at exuberant time of estrum, it fluctuated between 1～3ng/ml during the luteal phase. According to the changes of hormones and the results of rectal examination, the relationship between the levels of LH, P_4 and17β-E_2 and the function of ovary have been disccussed. It is concluded that oestrusof female yak should be decided by motionless, the ovulation occurs within 24 hours after luteinizing hormone peak appeared or the female stands when mounted by the teaser.