Trace Metal and Persistent Organochlorine Levels in Wood Bison (Bison bison athabascae) from the Mackenzie Bison Sanctuary

Abstract

Tissue samples were collected from ten healthy mature female wood bison (B. bison athabascae) for examination. Livers and kidneys were tested for toxic heavy metals and trace metals considered as essential nutrients for successful reproduction, while fat samples were analyzed for persistent chlorinated hydrocarbons. No elevated levels of toxic heavy metals (arsenic, cadmium, lead, mercury) were found and essential trace elements (copper, manganese, selenium, zinc) were within the acceptable ranges established for healthy cattle. All fat samples tested contained trace levels of α-BHC (mean value, 23 ppb) and lindane (mean value, 3 ppb).     

An Investigation of the Trace Element Status of Bison in Wood Buffalo National Park and of Ranch-Raised Bison in Saskatchewan,Canada

Abstract

Trace metal levels were compared in ranched bison receiving a dietary supplement and in wild bison in Wood Buffalo National Park. Data collected in this study were also assessed with regard to information previously published on healthy wild bison resident in the Mackenzie Bison Sanctuary. Ninety percent of ranched animals contained lead, with mean levels of 0.06 and 0.10 ppm in liver and kidney, respectively, while lead was present in only 20% of samples from wild bison. Similarly, arsenic was more prevalent in ranched animals, though at levels below 0.05 ppm. Cadmium levels were significantly higher in the wild bison and traces of mercury were also more prevalent in the wild herd.

Levels of copper, manganese, selenium and zinc, which are considered essential nutrients, showed variations between the ranched and wild bison, but were within the range considered acceptable for cattle, with the exception of selenium. This was found to be lower in the wild herd.

Further research is required to define the nutritional requirements of healthy bison. Variations observed in this investigation could be attributed to a variety of factors, including age, diet, and health status, which cannot be differentiated based on the available samples.     

Mathematical analysis of the transmission dynamics of brucellosis among bison

In this study, a mathematical model previously proposed for the transmission dynamics of brucellosis among bison was mathematically analyzed. Our qualitative and quantitative findings support the general hypothesis that the infection will vanish from the herd when the basic reproduction number R₀<1 and will persist otherwise. A global sensitivity analysis was conducted, and the results of the Sobol indices indicated that the rate of loss of resistance (δ) and the recovery rate (v) were responsible for most of the variability in the expected number of infectious bison. On the other hand, according to the partial ranked correlation coefficients, the density‐dependent reduction in birth (φ), the mortality rate (m), the transmission coefficient (β), and the recovery rate (v) exerted very high (and negative) correlations with the number of infectious bison, whereas the rate of loss of resistance (δ) and the calving rate (a) exerted very high (and positive) correlations with the number of infectious bison. Control measures should therefore aim at increasing the magnitude of φ, m, and v and reducing those of δ and a. In addition, experimental studies are needed to precisely estimate the rate of loss of resistance and the recovery rate in order to increase the accuracy of the expected number of infectious bison. Copyright © 2014 John Wiley & Sons, Ltd.