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.

Treadmill exercise in calves implanted with the AbioCor replacement heart.

The aim of this study was to evaluate the function of the AbioCor artificial heart implanted in calves that underwent treadmill exercise testing and to investigate the cardiovascular and metabolic responses during exercise. Six calves were implanted with the AbioCor. One week after surgery, exercise training was undertaken and animals were put on a treadmill at a speed of 0.