Areas of Molybdenum Toxicity to Grazing Animals in the Western States

Abstract

The geographic distribution of molybdenum (Mo) areas toxic for grazing animals was determined in five western states-Washington, Idaho, Montana, Wyoming, and Colorado. A number of relatively extensive areas producing forage plants with 10 to 20 ppm or more of Mo, levels well within the toxic range for grazing animals, was found. A history of a nutritional problem in animals was found to be associated with most of these areas. The characteristics of these areas are described and levels of Mo in forage plants as well as those of Cu are given. The concentration of Cu in forage plants was nearly the same whether the plants had small or large amounts of Mo.