INDICATIONS AND TECHNIQUE FOR THE SURGICAL REMOVAL OF THE AVIAN YOLK-SAC

Following the deaths of chicks of numerous avian species with retained yolk sacs due to infection or unknown causes, surgical removal of the yolk sac was attempted in 10 chicks of five species: four double-wattled cassowaries (Casuarius casuarius), three emus (Dromaius novaehollandiae), one bar-headed goose (Anser indicus), one lesser Magellan goose (Chloephaga picta), and one canvasback duck (Aythya valisineria). Candidates for surgery demonstrated one or more of the following clinical signs: swollen abdomen, dyspnea, exercise intolerance, inability to stand or walk, inappetence, weight loss, or failure to grow. Diagnostic tests included abdominal palpation and radiography. A doughy abdominal mass was usually palpable. Radiographs demonstrated an enlarged mass displacing the abdominal viscera cranially into the thorax. Seven of 10 chicks (70%) survived yolk sac removal and resumed normal development. Earlier recognition of surgical candidates would likely result in higher survival rates.