Surgical and anatomic study of calving paralysis.

Dissections of the bovine pelvic inlet region were made to determine which nerves were vulnerable to fetal-induced traumatic damage. Surgical sections of the obturator nerves and the lumbar roots of the sciatic (ischiatic) nerves were done to determine a possible cause of calving paralysis. Only 1 of 11 cattle in which bilateral obturator nerve section was done was unable to stand after the operation, and in this individual, secondary stifle injuries were found on necropsy. Subsequent surgical operations were performed on some of these cattle in order to section the lumbar root of the sciatic nerve. Of 6 cattle prepared, 2 were unable to rise after surgery and another 2 became "downer" cattle after 30 to 45 minutes of forces exercise. Also, some of these cattle were very ataxic and had intermittent fetlock flexion.