MANIFESTATIONS OF INTOXICATION BY SELENIUM-ACCUMULATING PLANTS

I. ABSTRACT A selenium-accumulating indicator plant, Astragalus bisulcatus, previously recognized as toxic and thought to be a cause of chronic selenium toxicity described as Blind Staggers, was fed experimentally to sheep. Clinical signs of emaciation, depression, neurological disturbances, and pathologic changes of neurovisceral cytoplasmic vacuolation were observed microscopically in the experimental sheep. These changes are similar to those observed in locoweed poisoning. It is suggested that the principle toxic agent (s) in Astragalus bisulcatus is similar to that of the true locoweeds rather than being selenium related. Further studies feeding other seleniferous indicator plants are being conducted.