Abstract
Ostium secundum-type atrial septal defects (ASD) were found in 44 of 243 bovine hearts with congenital cardiac anomalies except for patent foramen ovale. All defects were situated at the ostium secundum or fossa ovalis. Sinus venosus, coronary sinus or common atrium-type ASD could not be found. Eight of 44 ASD hearts were isolated ASD and 36 were associated with other various cardiac anomalies. Eight calves with isolated ASD died or necropsied prior to reaching 58 days of age due to either extracardiac anomalies, enteritis or rupture of the viscera. At necropsy, these calves showed no indication of congestive heart failure. Twenty-two of 44 ASD cattle showed extracardiac congenital defects. The incidence of ASD indicated no distinct correlation with the bovine species or bovine sex.
