Acute copper sulfate poisoning in yearling beef cattle in Brazil

In a herd of 70 crossbred beef calves (10-12-mo-old) managed extensively in Santa Catarina, Brazil, 14 animals developed clinical signs; 9 of the 14 died within 7 d of accidental ingestion of a copper sulfate (CuSO₄) product. Affected calves were lethargic, anorectic, and had green diarrhea. A bag containing remnants of blue-green product was found near the carcasses; this product was later determined to contain 53% metallic copper (Cu; dry weight). Postmortem examinations were performed on 3 calves found dead; tissue samples were collected for histopathology and mineral analysis. Gross findings included yellow-orange livers, distended gallbladders, green-blue intestinal contents, and hyperemic abomasal mucosae. Histologically, hepatic and renal necrosis varied in severity, with moderate Cu accumulation in both organs on rhodanine staining. Renal lesions were more prominent than hepatic lesions. Cu concentrations were 483 mg/kg in liver and 838 mg/kg in kidney; both were above RIs. Blood samples from 5 surviving calves were submitted for hematologic and biochemical testing; liver enzyme activities were elevated in most animals. We highlight the diagnostic value of kidney histopathology and toxicology in cases of acute copper toxicosis resulting from short-term, massive ingestion. To our knowledge, spontaneous acute CuSO₄ toxicosis has not been reported previously in cattle in Brazil.