Onset of oestrus and periovulatory events in sheep exposed to 5 and 14 days of CIDR treatment with and without eCG.

The present study supports that 5-day short-term CIDR treatments without administration of eCG are equally effective for inducing oestrus behaviour, preovulatory LH discharge and ovulation in sheep than classical protocols based on 14-day treatments plus eCG at CIDR withdrawal. However, the implementation of a 5-day protocol without eCG for fixed-time artificial insemination would be adapted to a later timing of ovulation (p < .05).