Also known as "ankylosing spondylosis," it can affect breeding bulls and multiparous cows following a chronic inflammatory process involving the lumbar vertebrae. This leads to the formation of exostoses that, starting ventrally from the vertebral bodies, extend to the intervertebral joints. The causes are to be found in a hereditary predisposition, but also in limb conformation defects or traumatic events at the lumbosacral level. Symptoms can vary based on the extent of the proliferative arthritic changes and the degree of compression of the roots of the spinal nerves. Initially, slight lameness or stiff gait with short steps may occur, followed later by severe motor disturbances. In more advanced situations, as in the case of the animal shown in the photo, an accentuated kyphosis of the thoracic vertebrae can be noted, associated with lumbar lordosis. When standing, the hind limbs remain extended backward. Over time, the animal's motor activity and production levels progressively and irreversibly decline, leading to prolonged recumbency and paralysis.
