<P> In the major sheep countries of Argentina, Uruguay, Brazil, Peru and Chile, breeders are also utilizing fleece testing and performance recording schemes as a means of improving their flocks . </P> <P> In 2008, for the first time in history, researchers at Chiswick CSIRO research station, between Uralla and Armidale, New South Wales have used stem cells to develop surrogate rams and bulls . These males then produce the viable semen of another male . </P> <P> The approach in these sheep experiments involves irradiating a ram's testes while placing stem cells from a second ram into the testes of the first, ram A . In the following weeks ram A produces semen the usual way, but is using the stem cells of ram B and therefore producing semen carrying the genetics of ram B rather than those of his own . Ram A therefore has effectively become a surrogate ram . </P> <P> The viable semen is then implanted in the ewe and the many lambs born through this process are proving to be normal and healthy . DNA tests have proved that up to 10% of the lambs are sired by the surrogate ram and carry the genetics of the donor ram . </P>

Do sheep have to be pregnant to produce milk