Priscilla, a four and a half year old Holstein cow, presented to the Large Animal Medicine Service of the Cornell University Hospital for Animals (CUHA) for evaluation of acute inappetance, weight loss, lethargy, watery diarrhea, and chronic hindlimb weakness. Three days after presentation, Priscilla developed signs of right-sided congestive heart failure including tachycardia, bilateral distended jugular veins, ventral edema, and a right-sided systolic murmur. She was also found to have tricuspid regurgitation, right atrial hypertension, bilateral pleural effusion, and hepatic congestion. Differential diagnoses for Priscilla's right-sided heart failure included endocarditis, cardiomyopathy, pericarditis, and heart failure secondary to pulmonary hypertension. No underlying cause of Priscilla's heart failure was determined. She was treated with digoxin, intravenous fluids, furosemide, and dexamethasone. Her clinical status did not improve with treatment and she was subsequently euthanized. Pathology revealed evidence of pulmonary vasculopathy that may have caused pulmonary hypertension and right-sided heart failure.