Effectiveness of orally administered cupric oxide needles in alleviating hypocupraemia in sheep and cattle.

The oral administration of a small dose of cupric oxide "needles" (CuOn), providing 0.5 g copper, to hypocupraemic ewes maintained on a copper-deficient diet alleviated hypocupraemia for 111 days when the diet was supplemented with molybdenum and sulphate and for 301 days when the diet was not supplemented. The same amount of copper given as cupric sulphate was approximately half as effective. The administration of a large dose of CuOn, providing 40 g copper, to hypocupraemic steers and heifers alleviated hypocupraemia for not less than 41 days, at which time a substantial reserve of copper (428 mg) remained in the liver. The absorbability of copper in CuOn was estimated to be 8.3 per cent and 3.8 per cent (depending on diet) for sheep. It was calculated that enough absorbable copper could be provided in a single dose to meet the net copper requirements of ewes for several years. This new form of copper therapy demands a totally different approach from that associated with parenteral copper usage.