Effets du protocole GPG sur l’activité ovarienne

The GPG protocol or OvSynch includes an injection of GnRH and followed seven days later by an injection of PgF(2alpha), which is preceded forty-eight hours earlier by a second injection of GnRH. The effects of GnRH on follicular tissue are either ovulation or luteinization depending at which stage of the cycle the cow is injected i.e. metoestrus, dioestrus or end of dioestrus. Observation of one or the other effect suggests a close association between the stage of follicular development, the function of the follicular tissue present and also the concentration of progesterone.