Separation of ewes from twin lambs: Incidence in several sheep breeds

The ability of ewes and their lambs to keep together during the first day or two of life, when the mother—offspring bond is consolidating, was examined in fine-wool Merino, Dorset Horn and Crossbred (Border Leicester × Merino ewes mated to a Suffolk ram) sheep, lambing on a sparse pasture in the Armidale district of N.S.W., and in a Romney flock, lambing on good pasture in the Mangakino district of New Zealand. Ewes in the N.Z. flock had been selected for their ability to rear more than one lamb.

46% of the twin-bearing Merinos became permanently separated from a lamb, mostly on the day after giving birth, and in at least 54% of these cases these was no obvious precipitating factor such as birth difficulties or interference by other sheep. In addition, a further 34% of twin-bearing Merinos experienced temporary separation from one lamb. By contrast, in the other flocks, permanent separations were 17, 0 and 8%, respectively, and some precipitating factor could always be identified. Few separations were associated with human interference.

The sheep at Armidale moved from the birth-site much more rapidly than the Romneys (means of 2 h versus 6.5 h), possibly due to sparse pasture conditions. In the Merinos, the proportion of separations decreased as the time that ewes remained near the birth-site increased. The observations indicate that fine-wool Merino ewes are slow to recognize the size of their litters and inherently poor at maintaining contact with more than one lamb in the neonatal period.