屡配不孕育成牛的临床与内分泌研究

对５头屡配不孕育成牛的临床与内分泌学研究发现，有的发情持续时间和发情排卵间隔时间较长。经适时追加授精，在１个情期内，４头实验牛中有３头受孕。实验牛在非授精发情周期和授精发情周期的外周血浆Ｐ４和ＰＧＦＭ无异常变化，说明这些牛的屡配不孕与管理因素有关

Clinico Endocrinal Study in Repeat Breeder Heifers

A detailed clinico endocrinal investigation was performed in 5 repeat breeder heifers (RBH). The heifers were first studied during an open cycle and thereafter during an inseminated cycle. Significant abnormality was not observed in the plasma levels of P 4 and PGFM while 3/4 heifers became pregnant after a variable number of inseminations (1 3) during the inseminated cycle since the estrous period was found to be prolonged and the ovulation delayed in the RBH. The results suggested that the management might be an important cause of the RBH syndrome, and that additional inseminations in the herd would increase the pregnant rate in repeat breeders.