Selenium Concentrations in Forages of a Northern Herbivore

Abstract

ABSTRACT. The importance of adequate selenium in diets of native wild herbivores can only be inferred from data for beef cattle where minimum dietary concentrations range from 50 to 100 ppb. Concern about possible selenium deficiencies in wild herbivores is based on a few reports of symptoms in wildlife, a paucity of data on selenium in their forages, and the idea that excessive atmospheric sulfur may increase the incidence of selenium deficiencies in herbivores. Concentrations of selenium in sedges, Carex spp., and reedgrasses, calamagrosris spp., the main food plants of bison, Bison bison, in northwestern Canada, varied from 9 to 800 ppb in samples collected at three lowland locations. However, approximately threequarters of all the samples of plant species consumed by bison were dietarily deficient by the beef cattle standard. Key words: Carex, calamagrostis, bison, selenium concentration &UMfi. L'importance d'un quantit6 adkquate de sklbium dans les rCgimes des herbivores sauvages locaux ne peut &re infCr6e que d'apks les donnh portant sur le Mtail bovin, dans lequel les concentrations minimales varient entre 50 et 100 ppb. La question d'insuffisance possible en dlenium chez les herbivores sauvages fut lev& par rapport h quelques etudes des sympt8mes d'animaux sauvages, la p6nurie de donnh sur le dlCnium dans leur rkgime et h la hypothhe selon laquelle un ex& de souffre dans I'atmosphZxe pourrait augmenter I'incidence d'insuffisance en &lCnium chez les herbivores. Les concentrations de dlCnium dans les laiches (Carex spp.) et les gourbets ( C h g r o s t i s spp.)