Possible contributions of nutritional interactions to copper deficiency in ruminants in South Australia

Abstract

Copper deficiency in sheep and cattle continues to occur in the cereal-pasture zones of South Australia (Cunningham 1974; Hannam and Reuter 1977) even though remedial measures are well known. To examine possible causes, two surveys were undertaken involving the collection and chemical analysis of a wide range of cruciferous plant species and companion pasture legumes (principally annual Medicago species). Plant samples were analysed for copper and for the elements sulfur, cadmium, molybdenum and zinc, which are known to interact with copper in the diets of ruminants. The crucifers had on average lower copper, but far higher concentrations of total sulfur, sulfate sulfur and cadmium than the companion legume species. Concentrations of zinc and molybdenum were similar for both plant groups. The survey data suggest that diets containing appreciable quantities of cruciferous species could induce copper deficiency in ruminants.