Ceruloplasmin concentrations and superoxide dismutase activity in the blood or red blood cells can be useful indicators of copper status. Specie Effects Dietary copper requirements vary greatly among species. The recommended levels for one specie may cause toxicity in another. By comparison, growing pigs are often fed 100 to 250 ppm of copper in the diet to improve growth. According to the National Reserch Council, poultry require approximately 8 ppm copper.
Sheep are unique in that they accumulate copper in the liver more readily than other farm animals.
Usually there are no clinical signs until there is a sudden release of copper into the blood. Plasma copper levels then increase 10 to 20 fold. The most common symptoms are anorexia, excessive thirst and depression. Most sheep will die within 2 to 4 days after blood concentrations sky rocket. Because of the variation in recommended copper concentrations, it is difficult to have one copper level in a trace mineralized salt for all species.