PMSG诱导的双胎母牛血清中P_4、LH、E_2的变化及与单、双胎的关系

CHANGES OF P 4,LH AND E 2 LEVELS IN SERUM OF TWIN AND SINGLE PREGNANCY COWS TREATED WITH PMSG

于发情周期的第１０天，给１２头参试母牛肌注ＰＭＳＧ（孕马血清促性腺激素，总剂量为１３５０～２０００ＩＵ）。每头参试牛于肌注ＰＭＳＧ前的当天，肌注后２４ｈ、４８ｈ，肌注氯前列烯醇后２４ｈ、４８ｈ，发情后４８ｈ，排卵或妊娠５、１０、２０、６０ｄ，从颈静脉各采血１次，共采１０次，每次１０ｍｌ，离心后分离血清。用放免法测定上述各生理时期血清中Ｐ４（孕酮）、ＬＨ（促黄体素）、Ｅ２（雌二醇）水平。结果表明，适量的ＰＭＳＧ（１３５０～２０００ＩＵ）能诱导母牛产双胎，其双胎率为４２．９％（３／７）。测定早期妊娠母牛（５、１０、２０、６０ｄ）血清中Ｐ４水平，证明双胎牛均高于单胎牛。

Twelve cows were injected intramuscularly(i m )with PMSG at 1 350 IU to 2 000 IU on the 10th day of the estrus cycle.Blood was collected from cows’ jugliar vein on the 10th day of the cycle,at 24 h and 48 h after injection with PMSG,at 24 h and 48 h after i m injection with cloprostenol,at 48 h after estrus,and on 5,10,20 and 60 d after ovulation or pregnancy.Serum was prepared and the levels of P 4,LH and E 2 in serum of the cows were measured by RIAs.The results showed that PMSG could induce twin pregnancy of the cows,twinning rate being 42 9%(3/7).Average levels of P 4 in twin pregnancy cows on 5,10,20 and 60 d after pregnancy were higher than those of single pregnancy cows.