Lithium toxicity in cattle.

Eighteen mixed-breed beef cattle died as the result of consuming "tacky lithium grease" discarded from a rubber reclaiming plant. Four experimental groups of mature cattle were given oral doses of a lithium salt at levels of 0, 20, 500, and 700 mg/kg body weight. Although all animals in the 250 mg/kg group showed signs of intoxication, the signs were mild and transient. Doses of 500 and 700 mg/kg proved toxic and fatal. Signs, serum levels, and tissue-organ deposition were dose and time-related. Signs of intoxication were salivation, depression, anorexia, hypodipsia, anuria, and diarrhea. The high dose group also showed severe depression and ataxia. The highest mean lithium serum values were 19, 40, and 54 ppm for the 250, 500, and 700 mg/kg groups, respectively. Postmortem and histopathologic examinations revealed dose-related gastroenteritis, slight interstitial nephritis, and hepatic cirrhosis. Tissue residues of lithium were in striated muscle (86.8 ppm), heart (79.3 ppm), liver (68.7 ppm), kidney (67.1 ppm) , and brain (51.8 ppm), in the high dose group. Since serum levels of cattle consuming the "tacky lithium grease" were 0.49 ppm of lithium, we believe other contaminants in this discarded grease may have caused or enhanced the toxic effect of lithium.