The effects of supplementary copper and a mineral mix on the development of lupinosis in sheep.
1994
White C.L. | Masters D.G. | Roe S.P. | Barnes M.J. | Paynter D.I. | Howell J.McC. | Allen J.G.
There were 3 dietary treatments applied at 2 levels (either present or absent) to 40 Merino wethers for 8 weeks. Treatments consisted of adding Cu (10 mg Cu as CuSO4 per kg), minerals (25 g per kg as Siromin) and toxic lupin stubble (50 g per kg) to a basal diet consisting of oaten hay and lupin seed and containing 3 mg per kg of Cu. Toxic lupin stubble decreased feed intake and growth, increased plasma activities of liver enzymes and increased plasma concentration of protein, globulin, bilirubin, Cu and Zn. It also decreased concentrations of Zn and Fe in liver, but had no effect on Cu. The mineral mix had no adverse effects on any signs of lupinosis, and it did not increase liver Cu concentration at either level of dietary Cu. The mineral mix prevented the inappetence caused by lupinosis in sheep fed the low Cu basal diet. Cu treatment resulted in increased concentrations of Cu and Fe in liver, and exacerbated some signs of lupinosis. The results show that the mineral mix is safe to feed to sheep grazing toxic lupin stubble, and it may provide a practical means of supplying additional Zn. The exacerbation of signs of lupinosis by the addition of only 10 mg Cu per kg as CuSO4 suggests that under field conditions the supply of Cu in the absence of suitable amounts of Mo and S should be kept to a minimum.
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