Single umbilical artery and other congenital defects in a calf.

Single umbilical artery, a common anomaly of humans is often accompanied by caudal and other vascular defects. A literature search failed to reveal any cases reported in animals. Dissection of a neonatal Holstein bull calf disclosed the following congenital defects: single umbilical artery with anomalous origin, abnormal abdominal aorta, azygos continuation of the caudal vena cava, rectal atresia, rectourethral fistula, abnormally shaped urinary bladder, unilateral testicular agenesis, undescended testis, unilateral renal agenesis, bifid ureter, and hydroureter.