Breeding ewe lambs at 7 to 10 months of age can increase lifetime reproductive performance when compared with ewes that do not lamb within their first year. It is suggested that early lambing at 12 to 15 months of age (early puberty ewes) results in more twins in the ewe’s lifetime. This has many benefits to a sheep operation by improving lifetime lamb production (as much as 10 to 20%) and increasing profits. Despite this clear advantage, breeding ewe lambs may not be for everyone, and disadvantages include an increase of management, feed (more nutritive-dense), and labor associated with ewe lambs compared with mature ewes. Therefore, it needs to be decided prior to breeding whether breeding ewe lambs is the right fit for your operation.
It is important to remember that ewe lambs are still growing and are immature. This requires an increased level of management and quality feed.
Factors Impacting Reproduction
Reproduction is affected by many factors, however, one important consideration on whether to breed ewe lambs should be liveweight. Ewe lambs should be roughly 65 to 75% of their mature body weight and a body condition score of 3. Any factors affecting liveweight gain prior to breeding (feed, health, etcetera) can influence their ability to breed. Ewe lambs should be fed to continue gaining throughout their reproductive cycle. It is suggested that ewe lambs should be able to maintain a rate of gain of 0.4- to 0.5 pounds per-day of growth before and throughout breeding.
During the breeding season, ewe lambs can be ‘shy’ breeders, exhibiting poor breeding behavior and being less likely to seek out a ram when in estrus. To increase the chance of successful breeding use of teaser rams, increasing the number of ewes per-ram and keeping ewe lambs separate from mature ewes during the breeding season can help increase the chance of success. The recommended ram-to-ewe ratio is 1-to-25 or 1-to-35. It is important to keep in mind that, even with great reproductive management, lambing percentages for ewe lambs are often lower.
During pregnancy and lambing, nutrient requirements will be increased compared with mature ewes, likely requiring separate pens or pastures for the ewe lambs. It is important that the ewe lambs are fed to maintain themselves, their lamb, and that they still have extra to be able to continue to grow. This means compared with a mature ewe, ewe lambs will need more nutritive-dense feeds during maintenance through late gestation, where getting enough nutrients can be a challenge depending on the quality of feed (see Figure 1, values are sourced from the NRC, 2007 and are based on a 176-pound mature ewe raising twins, and a 132-pound ewe lamb raising twins.). In addition, greater supervision and help may be needed to minimize lamb death loss in the lambing barn. Lambs born to ewe lambs are often lighter weight and the chances of lamb losses are greater for ewe lambs.
A common concern that often surfaces is, how does breeding ewe lambs affect their future weight and performance? The short answer is that it doesn’t. Breeding ewe lambs does not have a permanent effect on mature weight. Studies have indicated that live weight, condition, and reproduction performance maybe reduced in yearlings that were bred as ewe lambs. However, they catch up in body weight and their overall lifetime performance (number of lambs produced) is greater than those who didn’t breed and lamb as ewe lambs. This makes any temporary reduction in performance negligible. Moreover, there has been no negative effect observed on longevity of ewes bred as lambs up to 6 years of age.
Overall, with the increase in management and feed requirements this will equate to a greater need of labor. However, breeding ewe lambs may lead to an increase in the long-term productivity of your flock and therefore, profitability. These factors need to be considered when deciding whether breeding ewes is right for you and your operation.