The effect of a molybdate and sulphate supplement on the accumulation of copper in the livers of penned sheep

Abstract

Abstract Four groups of 10 ewes each were housed in pens and fed, ad lib., a basal diet of lucerne chaff. A summary of additional treatments, given in the form of feed concentrates, is as follows:— Group 1 : 4 oz of sheep nuts containing added sodium molybdate and calcium sulphate. Group 2 : 4 oz of sheep nuts containing added calcium carbonate. Group 3 : 4 oz of sheep nuts only. Group 4 : 16 oz of sheep nuts only. Analyses of feed components showed that copper concentrations were within normal limits. Nevertheless, two sheep in group 4 died from copper poisoning, about 15 months after the start of the experiment. After 14 months mean serum glutamic oxalacetic transaminase (SGOT) activities for groups 2, 3, and 4 were each greater than those for group 1, the differences in the cases of groups 2 and 4 being statistically significant. By means of liver samples taken by biopsy it was found that, over a 14-month period, mean liver copper concentrations (on a dry weight basis) had increased by 228 p.p.m., 798 p.p.m., 769 p.p.m., and 1,210 p.p.m. for groups 1, 2, 3, and 4 respectively, the differences between means for groups 2, 3, or 4 being statistically significant as compared with that for group 1. The differences between the means for group 2 or 3 as compared with that for group 1 were also significant. It was concluded that some dietary factor, probably associated with the concentrate, facilitated excessive storage of copper in liver, and that rate of accumulation was greatly reduced when a supplement of molybdate and sulphate was given.