Toxic effects seen in a herd of beef cattle following exposure to ash residues contaminated by lead and mercury

Abstract

Lead poisoning was diagnosed in three cattle along with increased mercury levels in the liver and kidney tissues of two of these animals. The clinical signs were different in each case and included salivation, anorexia, delayed menace response, delayed withdrawal reflex, head pressing, localized muscle fasciculation, reduced tongue tone, ataxia, rumen atony and seizures. Blood lead concentration was increased in all three cases to 0.76, 0.37 and 0.454 ppm. Post mortem changes characteristic of lead poisoning were only recognized in one case and included cerebro-cortical oedema, cortical neuronal necrosis and endothelial proliferation, especially at the tips of the cerebral gyri. The animals were poisoned by ingestion of lead-contaminated ash residues from a bonfire. The abnormal levels of mercury in the liver and kidney tissues of two animals may also be at least partly attributable to the intake of the metal in the ash residues. The levels of mercury in the three samples from the ash residue were relatively low (1.31, 0.7 and 2.1 ppm).