RESUMEN
BACKGROUND: Type-4 abomasal ulcers (U4) are perforated ulcers causing diffuse peritonitis. This retrospective study describes the clinical, laboratory and ultrasonographic findings in 38 calves with U4. The medical records of 38 calves aged three days to 20 weeks with U4 were scrutinised. RESULTS: The most common clinical findings were poor general health (95%), reduced skin elasticity (95%), rumen atony (91%), abdominal guarding (76%) and positive percussion auscultation and/or swinging auscultation on the right side of the abdomen (75%). The most frequent laboratory findings were increased numbers of segmented neutrophils (87%), eosinopenia (87%), acidosis (84%), azotaemia (79%) and hyponatraemia (79%). The most frequent abdominal ultrasonographic findings were intestinal atony (68%), fluid (67%) and fibrin deposits (58%) in the abdomen. Thirty-five calves were euthanased and three calves died spontaneously. All calves underwent pathological examination. Diffuse peritonitis caused by a transmural abomasal ulcer was the principal diagnosis in all calves. CONCLUSIONS: Perforated abomasal ulcers cause severe illness, and a thorough clinical examination combined with ultrasonographic abdominal examination should lead to a tentative diagnosis.