COMPARATIVE-STUDY OF COPPER AND ZINC-METABOLISM IN CATTLE AND CAMEL

At an experimental farm, five camels and five cows were fed a similar basal diet for 6 mo. They received oral trace element supplementation for 3 mo (day 22-112). This supplementation included zinc, copper, sel enium, manganese, iodine, and cobalt, and corresponded to twice the re quirements generally recommended for cows. Plasma copper and zinc conc entrations were significantly lower in the camels (61 mu g/100 mL for copper and 38 mu g/100 mL for zinc) than in the cows (111 and 83, resp ectively). The supplementation had no effect on plasma zinc concentrat ion in the camels in spite of the low observed values in this species. Liver copper concentration at the beginning of the trial was lower in the camels (9 ppm) than in the cows (35 ppm), and stayed at lower lev els during the entire supplementation period. There was no clear diffe rence in fecal excretion of copper and zinc between the camels and the cows. The results suggested that trace element requirements are lower in camels than in cows and that camels regulate their plasma zinc con centration at a very low level (<40 mu g/100 mL).