RESPONSE OF EWE TO PREGNANT MARE SERUM AND TO HORSE ANTERIOR PITUITARY EXTRACT

When compared in ewes at three dose-rates horse anterior pituitary extract (HAP) produced a different ovarian response to that of pregnant mare serum gonadotrophin (PMSG). Although there was no difference in number of ovulations, there was a greater number of persistent follicles after PMSG. Because persistent follicles are associated with a decreased percentage of fertilized ova, HAP is more suited than PMSG to the production of large numbers of fertilized sheep ova.