Plants that will accumulate selenium but do not have a requirement for it are called facultative or secondary selenium absorbers. These plants can accumulate up to 50 ppm. The secondary selenium accumulators include some native range plants, and crop plants such as western wheatgrass, barley, wheat, and alfalfa. Plants containing more than 5 ppm selenium are potentially toxic in cattle. Where Selenium-Accumulating Plants Grow The major seleniferous areas of the West can be found in North and South Dakota, Montana, Wyoming, Colorado, and Utah.
Selenium poisoning occurs in the areas that have soils high in selenium.
Both indicator and secondary selenium-accumulating plants grow in these areas. Though it is not palatable to most livestock, it has been implicated in some cases of selenium toxicosis. It has been suggested that even though selenium accumulating plants are not readily eaten, they contribute to selenium toxicosis by making selenium in the soil available to neighboring, palatable, secondary selenium-accumulating plants. How It Affects Livestock Selenium is required in the diet of most animals. Concentrations of 0.3 ppm are recommended for most food producing livestock.