Monensin toxicosis in the domestic bovine calf: a large animal model of cardiac dysfunction.

A large animal with diminished cardiac function would be desirable for chronic testing of pathophysiologic responses to many human-sized devices and other therapies, especially if this model did not require prior surgical interventions or extensive technical skill and expense. Overdoses of monensin, widely used in the cattle industry as a growth promotant, are cardiotoxic, suggesting its possible use in creating cardiomyopathy. We gave a single oral dose of monensin (20 to 40 mg/kg) to 13 calves (55 to 90 kg) to produce diminished cardiac function.