Domestic Sheep Reproduction - Lambing

Lambing

When birth is imminent, contractions begin to take place, and the fitful behavior of the ewe may increase. A normal labor may take one to several hours, depending on how many lambs are present, the age of the ewe, and her physical and nutritional condition prior to the birth. Though some breeds may regularly produce larger litters of lambs (records stand around nine lambs at once), most produce either single or twin lambs. At some point, usually at the beginning of labor or soon after the births have occurred, ewes and lambs may be confined to small lambing jugs. These pens, which are generally two to eight feet in length and width, are designed to aid both careful observation of ewes and to cement the bond between them and their lambs.

Ovine obstetrics can be problematic. By selectively breeding ewes that produce multiple offspring with higher birth weights for generations, sheep producers have inadvertently caused some domestic sheep to have difficulty lambing. However, it is a myth that sheep cannot lamb without human assistance; many ewes give birth directly in pasture without aid. Balancing ease of lambing with high productivity is one of the dilemmas of sheep breeding. While the majority of births are relatively normal and do not require intervention, there are still a large number of possible complications that may arise. A lamb may present in the normal fashion (with both legs and head forward), but may simply be too large to slide out of the birth canal. This often happens when large rams are crossed with diminutive ewes (this is related to breed, rams are naturally larger than ewes by comparison). Lambs may also present themselves with one shoulder to the side, completely backward, or with only some of their limbs protruding. Lambs may also be spontaneously aborted or stillborn. Reproductive failure is a common consequence of infections such as toxoplasmosis and foot-and-mouth disease. Some types of abortion in sheep are preventable by vaccinations against these infections.

In the case of any such problems, those present at lambing (who may or may not include a veterinarian, most shepherds become accomplished at lambing to some degree) may assist the ewe in extracting or repositioning lambs. After the birth, ewes ideally break the amniotic sac (if it is not broken during labor), and begin licking clean the lamb. The licking clears the nose and mouth, dries the lamb, and stimulates it. Lambs that are breathing and healthy at this point begin trying to stand, and ideally do so between a half and full hour, with help from the mother. Generally after lambs stand, the umbilical cord is trimmed to about an inch (2.54 centimeters). Once trimmed, a small container (such as a film canister) of iodine is held against the lamb's belly over the remainder of the cord to prevent infection.