Trace elements status of white-tailed deer (Odocoileus virginianus) and moose (Alces alces) in Nova Scotia

The province of Nova Scotia is considered to have two moose (Alces alces) populations. In 2003, the moose of the mainland area of the province were formally listed “ENDANGERED” under the Nova Scotia Endangered Species Act. To date, the specific causes of the Mainland moose population decline have not been determined. Trace element imbalances have been considered as a potential etiology for the population decline. Liver and kidney samples were collected from white-tailed deer (Odocoileus virginianus) and moose throughout Nova Scotia during the fall and winter 2000-01 to compare trace element concentrations between the two species, in relation to age, gender and location and to other areas. All samples were analysed for arsenic, cadmium, cobalt, copper, lead, manganese, nickel, selenium and zinc. Tissue concentrations of trace elements in deer and moose in Nova Scotia appear to be generally similar to levels reported in cervid populations elsewhere in North America and Europe with the exception of zinc and possibly cobalt which appear to be lower in Nova Scotia. Kidney cadmium concentrations are high in some Nova Scotia moose (geometric mean: 60.4 μg/g dry weight [95%CI: 40.3 90.6]), however, similar or higher concentrations have been reported in other regions. Relative to reference values for domestic cattle, cobalt, copper, manganese, selenium and zinc levels in some animals are deficient or marginally deficient. At the present time, there appears to be little supporting evidence that clinical deficiencies of any of these trace elements are occurring in Nova Scotia moose or deer populations. However, the possibility that marginal or deficient levels of these or other trace elements and high levels of cadmium may impact the health of individual animals either directly or through interactions with other factors (eg. infectious and non-infectious diseases, harsh environmental conditions, habitat limitations) cannot be dismissed. Recommendations for continued monitoring of trace element concentrations in these populations are made.