A 6-day-old, female roan antelope (Hippotragus equinus cottoni) was diagnosed with a single intrahepatic portosystemic venous shunt at necropsy. Clinical signs had included weakness, lethargy, hypothermia, diarrhea, and a weak suckle response. Multiple seizure episodes were associated with hypoglycemia and characterized by vocalization, muscle fasciculations, and disorientation. Hematologic abnormalities included anemia with hypochromasia, anisocytosis, poikilocytosis, and leukopenia with neutropenia and lymphopenia. Serum biochemical abnormalities included elevations in blood urea nitrogen and total serum bile acid concentration. A portosystemic vascular anomaly should be a differential diagnosis for nonthriving, exotic ruminant calves with overt or subtle neurologic signs, persistent hypoglycemia, and/or elevated bile acids. In very young calves, total bile acid concentration may be more useful in establishing a diagnosis than blood ammonia concentration.