acute selenium poisoning in cows and sheep caused by ingestion of plants with high selenium content (accumulator plants termed seleniferous). Clinical signs include ataxia, altered behavior (e.g., bellowing), wandering behavior, impaired vision, paresis; glossal and pharyngeal paralysis occurs in cattle. At high doses, a peracute course ends with respiratory arrest. Referred to as sheep staggers in sheep. SYN: acute selenium poisoning.