In face of the ongoing demand to reduce the interval within deliveries to increase sheep reproductive efficiency, the male effect could be used to shorten anestrus postpartum in ewes. The male effect is a simple, effective and low-cost approach to reducing the duration of postpartum anestrus without affecting pregnancy rates. In conclusion the male effect can be used with postpartum ewes that have lambed within 35 to 40 days previously in order to decrease time between deliveries.