Copper deficiency prophylaxis in grazing sheep by copper oxide injection.

21 ewes weighing about 46 kg were transfered to grass on a copper deficient Rye Grass pasture. 11 ewes were injected intramuscularly with 60 mg of copper as copper oxide (CuO) suspended in 5 ml of purified olive oil. The concentration of copper in the plasma of control ewes declined during the 67 days of experiment and three became copper deficient. The injected ewes were protected against deficiency and had higher concentration of copper in plasma than the controls throughout the experiment. At slaughter the amount of copper in the liver of the treated animals was significantly higher than in the untreated controls. The copper dose used (60) mg) is probably a maximum for adult sheep since one of the injected ewes at slaughter had a liver copper content of 1060 micrograms/g D.M. which approaches the toxic limit.