A 24-day-old female Japanese Black calf presented a sudden paraplegia after a history of watery diarrhea. Antemortem magnetic resonance imaging confirmed the suspicion of thrombotic component in the abdominal aorta, without any spinal cord abnormality at the lumbar region. On necropsy, a massive thrombus occupied the lumen from the distal abdominal aorta to the bifurcation of the external iliac arteries. In the thoracic aorta, another mural thrombus developed from the caudal side of the incompletely closed ductus arteriosus orifice, with aortic wall erosion. Both thrombi were mainly composed of platelets. Any microbes were undetected during organ and thrombus incubations. A saddle embolism in the abdominal aorta occurred by an abacterial white thrombus suspiciously originated from the thoracic aortic mural thrombus.