Production responses in selenium supplemented sheep in northern New South Wales. 2. Liveweight gain, wool production and reproductive performance in young Merino ewes given selenium and copper supplements

Abstract

Young Merino ewes on five commercial properties in northern New South Wales were supplemented with selenium and their production was compared with untreated flock mates. They were studied from weaning till first lambing at about two years of age. Treatments of 5 mg selenium were given orally every six weeks for approximately 12 months. Copper treatments were also included to test for a possible concurrent deficiency or interaction with selenium. There were significant responses to selenium in liveweight in four of the five flocks and in wool production in two of the flocks at both shearings. Reproductive performance at first mating was also significantly better in two flocks. There were no beneficial effects of copper treatment nor were there any significant interactions with selenium treatment in any aspect of production measured.