Myocardial toxicity in two dogs with natural exposure to ractopamine

Abstract Two dogs that lived in a farm setting were presented to the Texas A&M University Veterinary Medical Teaching Hospital's Emergency Service exhibiting muscle tremors and ventricular arrhythmias following ingestion of ractopamine, a ß‐2 agonist feed‐additive used in beef cattle, pigs and turkeys intended for slaughter to increase muscle mass. The dogs had similar initial clinical signs and treatment, but markedly different disease progression and outcomes, likely due to early decontamination in one of the dogs but not the other. Both dogs developed hypokalaemia and ventricular tachycardia during their hospitalisation period. Severely elevated cardiac troponin I concentrations in both dogs were consistent with marked cardiac damage as a result of ractopamine ingestion. The degree of cardiac damage proved fatal in one dog, but was survivable with no long‐term ramifications in the other.