The present study supports that 5-days short-term CIDR treatments without administration of eCG are equally effective for inducing estrus behavior, preovulatory LH discharge and ovulation in sheep than classical protocols based on 14-days treatments plus eCG at CIDR withdrawal. However, the implementation of a 5-days protocol without eCG for fixed-time artificial insemination would be adapted to a later timing of ovulation (p < 0.05).