Analysis of data collected in a residue survey: copper and zinc concentrations in liver, kidney and muscle in Australian sheep and cattle

Abstract

Samples of h e r , kidney and muscle were collected between 1975 and 1983 from 2797 sheep or cattle at 39 meatworks located in all Australian States and the Northern Territory on behalf of the Australian Bureau of Animal Health. The samples were analysed for copper (Cu) and zinc (Zn) at government analytical laboratories. Mean values and proportions falling into various class intervals are presented. Hepatic Cu concentrations tended to be positively skewed with a long tail of observations with high concentrations. About 3% of ovine livers and 9% of bovine livers contained <2 mg Cu/kg freshweight when calculated on a national basis. This concentration was arbitrarily taken as the criterion of a low Cu status, and the proportion within States falling into this class ranged from about 1% in sheep from Queensland, Western Australia and Tasmania to about 11% in Victoria. Proportions in cattle were highest in Victoria, Queensland and New South Wales, and were 13.6, 10.5 and 8.9% respectively. Correlations between Cu and Zn concentrations in the different tissues were low. Possible sources of bias in applying the results to predicting the number of Cu-deficient animals in the various States are discussed.