Studies in the copper metabolism of sheep: A dissertation submitted in partial fulfilment of the requirements for the degree of Bachelor of Agricultural Science with honours in the University of Canterbury

Abstract

Two trials were set up using a concentrate feed high in dietary sulphur (4g/kg) and molybdenum (73 mg/kg). Trial 1 was designed to study the effect of the diet on liver and plasma copper concentrations of ram lambs, prior to the infection of animals with gastro-intestinal parasites. Trial 2 assessed the stability of TCA insoluble copper in plasma samples under various storage conditions. In trial 1 some animals developed urolithiasis, possibly due to the high phosphorus (0.75%) and magnesium (2.4g/kg) content of the feed, and the second phase of the trial was abandoned. However, during the period when animals were still healthy copper levels were reduced (p ~ 0.001). Statistically significant correlations were found between dry matter intake and changes in liver concentration (r= 0.725, p < 0.05), initial liver copper levels and changes; in liver concentration (r= 0. 725, p < 0. 05), and between dry matter intake and levels of copper in the plasma. In the second trial, plasma from ewes with a high concentration of TCA insoluble copper was stored at 0 C, room temperature (20 C), or frozen and thawed repeatedly. The amount of TCA insoluble copper, present changed with time for all treatments (p~ 0.001). Improvements to trial techniques and suggestions for future research were discussed.