Abstract
Thirty beagles aged from 3 to 9.3 years in our breeding colony showed clinically gait abnormality due to intervertebral disc protrusion. The intervertebral discs were examined radiographically and anatomically for pathological changes. The radiographic images of symptomatic cases showed intervertebral disc protrusion and narrowed intervertebral spaces in the thoracolumber regions. Such alteration of the structure of the intervertebral disc as herniation of nucleus pulposus, degeneration and avulsion of fibers of annulus fibrosus were anatomically observed. The high incidence of such lesions seems to have been due to mainly stress to the vertebral column by disturbed motion under such an unacceptable breeding condition that three dogs were continuously housed together in a small cage for a long time from youth, in addition to spontaneous senile changes.
