Maduramicin poisoning in prepartum dairy cows due to cross‐contamination of anionic salts

Abstract Maduramicin is prohibited in ruminant feed due to its high toxicity. The aim of this study is to describe a case of maduramicin poisoning caused by industrial cross‐contamination of anionic salts in prepartum dairy cattle. The clinical signs observed included anorexia, depression, nasal discharge, salivation, reddish urine and haematochezia. Morbidity was 100%, and lethality was 85%. Macroscopic lesions were consistent with congestive heart failure, characterised by hydrothorax and pulmonary oedema. Histopathology showed coagulative necrosis in cardiomyocytes and pulmonary oedema. The CPK levels ranged from 26,386 to 53,398 U/L, while the LDH and AST levels were 18,462 and 3610 U/L, respectively. The concentration of maduramicin in anionic salts was 7000 ppm. The combination of epidemiological, clinical, anatomopathological and analytical evidence allowed us to conclude that the mortality was a result of maduramicin consumption from the anionic salts.