Complex congenital heart defects in three Holstein Friesian calves

Congenital heart defects are uncommon in cattle, being reported a prevalence < 0.2% in two large necropsy studies, and the most frequently encountered anomalies are represented by ventricular and atrial septal defects. The aim of this article is to describe clinical, ultrasonographic and pathological findings of complex congenital heart defects in three calves of Italian dairy farms. The calves were examined for respiratory distress, stunted growth, or cardiac murmur. Clinical examination and echocardiography allowed to perform a diagnosis of ventricular septal defect associated to other congenital cardiac anomalies in all three calves. In case 1, a diagnosis of ventricular septal defect and complete transposition of the aorta and pulmonary artery was made. In case 2, an atrioventricular canal defect associated to persistent ductus arteriosus were diagnosed. A ventricular septal defect associated to atrial septal defect, dextroposition of the aorta and right ventricular hypertrophy were diagnosed in case 3. Echocardiographic findings were confirmed by post-mortem examination in all calves. Complex congenital cardiac defects represent a diagnostic challenge for veterinarians, but an accurate clinical and echocardiographic examination can be useful for an ante-mortem diagnosis and prognosis. Clinical signs as weakness, respiratory distress and heart murmur associated to a history of failure to thrive or respiratory disease unresponsive to appropriate therapy, are common in calves with congenital heart defects. Echocardiography is a readily available diagnostic tool and can be performed in veterinary hospitals as well as in farms. An ante-mortem diagnosis of congenital heart defects can be useful to discriminate between isolated anomalies, frequently characterized by a favourable prognosis, and complex anomalies, characterized by a guarded to poor prognosis. Finally, our case series can be important to update current knowledge of the complex congenital heart defects in cattle: atrioventricular canal defect and aneurismal dilation of Valsalva sinus associated to ventricular septal defect have been never reported in cattle.