Accelerated lambing means lambing more often than the conventional once-a-year approach. Since ewes are pregnant for five months and nurse lambs for only about three months, they can be considered idle four months of the year. It is possible to lamb ewes every eight months (in some cases, every six months). On the surface, this seems like a logical approach to efficient sheep production, but that is typically not the case. Even with use of hormones, the success of most accelerated lambing programs depends entirely upon the competence of management. Because of the increase in disease, stress, and death loss associated with lambing, accelerated lambing is likely to reduce the length of the ewe's productive life and increase feed, labor, and managerial expenses.
An accelerated lambing program necessitates that lambs be weaned early. The recommended hormone treatment is the same as for estrous synchronization in that progesterone should be administered for 10 to 12 days and followed immediately with an injection of 500 to 750 international units of gonadotropin, and again 16 days later. If the ewes are in an anestrous period, it is sometimes helpful to administer 2 milligrams of estradiol two days before the start of progesterone treatment.
Producers who lamb outside the natural season can expect some loss in reproductive efficiency. Only outstanding managers and those who can afford to experiment should try accelerated lambing.