The levels of copper, molybdenum and inorganic sulphate in some Western Australian pastures. A contribution to the study of copper deficiency diseases in ruminants

Abstract

Levels of copper, molybdenum, and inorganic sulphate are reported for samples of Western Australian pastures from areas where copper deficiency diseases in ruminants have occurred and from unaffected areas. The copper contents of the pastures were determined previously. It was found that the copper deficiency diseases commonly occurred where pastures contained less than 3 p.p.m. Cu in the dty matter during the growing period, while such diseases were absent where the pastures contained more than 6 p.p.m. Cu. Values between 3 and 6 p.p.m Cu were classified as marginal. The molybdenum and inorganic sulphate contents of the original pasture samples have now been determined. The molybdenum contents of the three classes of pasture were found to lie within the same range (0.1 to 4 p.p.m. Mo in the dry matter, with the majority less than 1 p.p.m.). These values are similar to those recorded by overseas workers for normal pastures. Inorganic sulphate contents of the three classes of pasture also lay within the same range (0.1 to 0.9 per cent SO4, with the majorio between 0.2 and 0.4 per cent). The results for the pastures examined suggest that in Western Australia the low copper level is the constant and the most significant factor associated with enzootic ataxia in sheep and falling disease in cattle.