The Booroola Merino was originally developed on the Southern Tablelands of NSW, and is the subject of a continuing development program initiated by the Commonwealth Scientific and Industrial Research Organization (CSIRO).
Booroolas differ from the normal Merino in two important ways. First, their fertility is as high as any breed in the world. The number of lambs born per ewe lambing averages 2.4 with a range from one to six. In crosses with other Merinos this difference is naturally reduced but half-Booroola ewes on average wean about 20 percent more lambs than comparable Merinos under the same conditions. Second, they have the ability to breed at most times of the year, thus extending the breeding season.