Zinc toxicity, copper deficiency and anaemia in swill-fed pigs.

Zinc toxicity, copper deficiency and an associated anaemia among weaned swill-fed pigs is described. The source of zinc was flaking galvanising from the inside of bins used to store swill before processing. The disease condition readily responded to supplementation of the diet with copper sulphate. The interactions between dietary zinc, copper and calcium are discussed with reference to the swill-feeding industry. It is concluded that supplementary copper should be routinely included in the ration of swill-fed pigs and that the use of galvanised bins for storing swill should be avoided.