Oxidized copper wire particles for copper therapy in sheep

Abstract

Ninety Merino weaner sheep were assigned to one of six groups on the basis of liveweight and liver copper concentrations. Sheep in four groups each received one oral dose of oxidized copper wire particles, viz. 2.5, 5, 10 or 20 g per animal. Sheep in another group each received a subcutaneous injection of 12 mg copper as diethylamino cupro-oxyquinoline sulfonate and another group of sheep did not receive any copper supplement. Liver copper concentrations responded positively to copper oxide load. The 2.5 g dose of copper oxide wire was more efficacious than the commercial injectable product in raising copper status, but the higher doses of oxide raised liver copper concentrations to values similar to those recorded in cases of copper poisoning. Copper concentrations in blood plasma, muscle and kidney were not altered by the copper load. No clinical signs, nor biochemical or histological evidence of acute copper toxicity, were found. Liver copper values fell in all sheep from 10 weeks after copper therapy until the end of the trial at 50 weeks post-therapy. Over this period of 40 weeks, the rate of mobilization of liver copper was linear and was positively related to the initial concentration of copper in the liver. A significant proportion of the oxidized copper wire dosed to sheep was recovered in the forestomachs and abomasa of selected sheep 4 weeks after dosing. No evidence of abomasal damage due to particles could be established. It is concluded that oral dosing of oxidized copper wire is a safe and effective method of copper supplementation to sheep.