SWOR, R.*; BLAKE, J.; BARBOZA, P.: Effect of a Dietary Copper on Muskox Calf Growth and Immune Function

There are three critical periods for muskox calf health and survival: gestation, the first week of life, and the transition from being a monogastric to being a ruminant. This study addresses the third time period. Preliminary data suggests that copper supplementation may improve calf health; however, little is known about copper requirements or trace mineral metabolism in muskoxen. Work on captive and free-ranging muskoxen indicates that calves utilize liver copper reserves accumulated during gestation but, since milk is a poor source, we suspect survival depends upon their rapid transition to solid feed containing adequate copper. We hypothesize that muskox calves weaned onto a diet marginal in copper will exhibit poor weight gains and be more susceptible to disease than calves fed the same diet but supplemented with injectable copper. Calves were fed a complete pelleted ration containing 5ppm copper, which is a marginal level for most species. The control group (n=6) received supplemental copper via weekly subcutaneous injection whereas the treatment group (n=7) received a sham injection. At 8-10 weeks-of-age the treatment group exhibited reduced or declining weight gains and a higher occurrence of enteritis compared to the control group. Three of the 7 treatment animals died or were euthanized due to illness between 13 and 16 weeks of age. Preliminary analysis of lymphocyte proliferation shows no difference between treatment and control groups for cell mediated responses. However, there were significant differences in antibody response to a benign vaccination and in total serum immunoglobulin. Muskox calves fed a diet marginal in copper during weaning and early growth show reduced weight gains, increased occurrence of disease and reduced humoral immune function. Funding provided by NSF Alaska EPSCoR grant and ASTF.