The practice of twice a year lambing offers increased opportunities for the sheep industry to expand production. The reproductive rate of sheep is determined by prolificacy and the frequency of lambing. Several experiments to breed ewes twice yearly have been reported involving many breeds of sheep (Land and McClelland, 1971; Copenhaver and Carter, 1972; Whiteman et al., 1972; Walton and Robertson, 1974; and Speedy et al., 1976). In these studies flock numbers were small and the sheep were generally managed under farm flock conditions.

The purpose of this study was to attempt to successfully breed and lamb certain genotypes of sheep twice-a-year under modified range conditions.