The comparative toxicity of species in calves.

and are toxic plants that contain the putative toxin tremetone. It is common for to poison livestock in the southwestern United States. has been suspected of poisoning livestock but its toxicity has not been confirmed by association with clinical poisonings or experimental studies. Jersey calves dosed with and for nine days developed "trembles" characterized by skeletal muscle degeneration and necrosis and large increases in serum creatine kinase activity. This is the first report of toxicity in an animal model. This study also demonstrates that remains toxic even though tremetone concentrations in the plant were low due to storage of the plant for over five years. Thus, supporting recent research which indicates that another toxin in the plant may be responsible for, or at least contributes to causing "trembles" in livestock.