Healthy, fast-growing lambs are the goal of sheep breeders. Sheep may be raised for wool, meat and/or milk production and all require basic care to successfully produce lambs.
Careful selection of ewes and rams for breeding is a necessity. The animals must be healthy and free of disease and parasites. Both ewes and rams require sound feet and legs and normal breed and sex characteristics. Ewes should have sound udders and rams should have well developed testicles. Ewes with hard or misshapen udders or teats and rams with small testicles should not be retained for the breeding program. Both ewes and rams must have all teeth present.
Sheep are seasonally polyestrus. This means ewes have regular estrus or heat cycles during part of the year. Ewes have regular heat cycles when the days are shorter and therefore fall is the common time for breeding. With a gestation length of five months, the ewes give birth during the late winter and early spring. Some breeds such as the Rambouillet, Merino, and Dorset are known for breeding out of season and may produce lambs during other times of the year. All ewes have an estrus or heat cycle of about 17 days. The ewes are in heat for 24 to 36 hours. If not bred during this time period, the ewes will be in heat again about 17 days later.
Ewe lambs may be bred to produce their first lambs at either one year or two years of age. If the ewe lambs are large and at least 70 percent of their mature weight, they may be bred at seven to eight months of age. It is recommended that slower maturing ewe lambs be bred at 18 to 19 months of age.
Ram lambs may first be used for breeding when they reach about eight months of age. A ram lamb can be expected to breed about 15 ewes, while a yearling ram will breed about 25 to 35 ewes during a breeding season. A mature ram will breed about 35 to 45 ewes. Some sheep producers attach a breeding harness to the rams. When the ram breeds ewes, a chalk mark is left on the lower back of the ewes. The producer can monitor the number of bred ewes and accurately determine the expected lambing date. There are also methods to synchronize estrus in ewes. Ewes will come into heat within a short time period and the lambs will be born within a short period of time.
Ewes give birth to an average of two lambs. Some breeds such as the Finnsheep are known for producing triplets or even more lambs. Flushing is a technique used to increase the number of lambs born for any sheep breed. The ewes and rams are fed extra or better feed during the time period of two weeks before and two weeks after breeding. Some producers move the sheep to a more lush pasture or feed concentrates such as corn or barley during this time period.
Adequate nutrition is especially important during the last six weeks of gestation. Ewes must receive adequate levels of protein and energy to produce healthy lambs. Producers often increase the energy level of the feed ration by feeding concentrates such as corn, oats or barley. Good quality hay or pasture is often used to provide an adequate level of protein.
Prior to lambing, some producers "tag" the ewes. Tagging involves shearing the wool around the ewe's udder, between the hind legs and around the tail area. Tagging removes long wool that can hinder a lamb's ability to nurse. It also allows the sheep producer to notice any problems with the udder.
At the time of lambing, it is important for the ewes to be in a dry, warm and clean area. Once the lambs are born, it is important they nurse to receive the benefits of the rich first milk or colostrum. Ewes identify their lambs by smell. Some producers place each ewe and her lambs in small, individual pens for one to two days or until it is obvious the ewe has bonded with the lambs. During cold weather, a heat lamp may be provided to keep the lambs warm.
Record keeping is very important for a successful sheep-breeding program. Many producers place an ear tag in each ewe's ear. The ear tag number identifies the ewe and the producer records the number of lambs born, birth weight, weaning weight, and other pertinent information. Records help determine which ewes and rams should be retained in the herd for breeding.
Artificial insemination is not used as frequently with sheep as with other livestock because of the structure of the ewe's reproductive tract. Similarly, embryo transfer is more difficult with sheep than in some other types of livestock.
With careful selection, management, and nutrition, the goal of raising healthy and fast growing lambs can be easily achieved.