Copper absorption, liver accumulation and development of copper toxicosis in sheep are influenced by a variety of other elements, in particular molybdenum, sulphur and zinc (Underwood 1977). In a previous study on liver concentrations of copper, molybdenum and zinc in normal and copper-poisoned sheep, no direct correlation was found between the concentrations of the three metals, but molybdenum was significantly lower in the livers from sheep dead from chronic copper poisoning than in normal animals (Frøslie & Norheim 1976).