Toxic effects of trace element excess.

Excesses of many trace elements can cause direct toxic effects to cattle as well as indirect effects that can cause a secondary deficiency of other trace elements. Clinical signs may vary from poor growth and feed utilization to neurologic disorders. Toxic effects vary with the specific trace element in question, the total amount of that element in the diet, the age and condition of the animal, and the presence or absence of certain other dietary components. A diagnosis of toxic trace element interaction is based upon compatible clinical signs in affected animals as well as supporting chemical analyses.