Copper-molybdenum-sulphate-manganese interaction and the copper status of cattle

Abstract

The influence of molybdenum, inorganic sulphate, and manganese upon the copper status of cattle was investigated. The mean liver copper concentration increased for steers on a basal diet containing 7.6 p.p.m. copper, 2.4 p.p.m. molybdenum, 91 p.p.m. manganese, and 0.03 per cent. sulphate. In steers on a similar diet but with the sulphate content increased to 0.55 per cent., with or without an increase in the manganese content to 391 p.p.m., there was a highly significant reduction (P=0.01) in the liver copper concentrations but not to low levels. There was also a significant (P=0.01) increase in the serum inorganic sulphate levels. On increasing the molybdenum content to 9.2 p.p.m. there was a further reduction, to low levels, in the liver and blood copper concentrations of steers on the high sulphate diets but there was no definite effect on those on the low sulphate diet. Manganese again appeared to be without effect. It was concluded that there was a molybdenum-sulphate interaction with copper in cattle but that, under the conditions of this trial, manganese was without effect. Despite the very low liver and blood copper levels attained, and maintained for 15 weeks, there was no clinical evidence of hypocuprosis. The mineral and sulphate levels applied in some of these treatments are similar to those found in pastures from areas in New South Wales where copper deficiency in cattle occurs. The levels in pastures, as related to the results of this trial, are discussed.