Replacement Ewe Lamb Production
Livestock Update, June 1997
Steve Umberger, Animal and Poultry Sciences, Virginia Tech
Ewe lambs born in March and April are excellent candidates to be used as replacement ewes in spring-lambing flocks. With proper feeding and breeding management, spring-born ewe lambs should be in production by the time they are 12 to 14 months of age. Ewes lambing first as yearlings have a higher lifetime production than ewes lambing first as two-year olds. The fastest growing twin and triplet ewe lambs should be selected for replacements. Not only is there an advantage in improved prolificacy, but twin and triplet lambs have a more moderate growth rate, which prevents excess fat deposition in the udder. Lifetime milk production is reduced in ewe lambs grown at an accelerated rate before reaching puberty. Ewe lambs should weigh approximately 60 % of their mature body weight at the time of breeding. That equates to a weight of approximately 100 lb at breeding for most commercial crossbred ewe lambs. To ensure proper breeding weights, lambs should be sheared by July 15. They should be weighed in early August and, if necessary, supplemented with .5 to 1 lb of corn or barley to improve average daily gain. Starting October 20, ewe lambs should be exposed to rams for 50 days. Marking harnesses should be used on the rams to monitor breeding activity. Sixty days after ram removal, ewe lambs should be checked for pregnancy using real-time ultrasound. All lambs diagnosed as open should be marketed. To ensure proper development, ewe lambs should receive 1 lb of grain daily from breeding through lambing. To prevent excessively large lambs at birth, the grain portion of the diet should not be increased during late gestation.