1989 Volume 42 Issue 9 Pages 631-635
Spondylolisthesis was diagnosed in commercial broiler chickens of a certain line on three farms of Okayama Prefecture in September and October, 1987. Clinical signs of the affected birds, lameness and sitting on their hocks and keel, occurred from around 20 days of age, and were prominent at approximately 40 days of age. Such signs persisted until their processing age, showing a total morbidity of 3.6% to 4.4%. The radiography of the birds revealed various degrees of deformation of the 5th to 7th thoracic vertebrae, particalarly dorso-ventral rotation of the 6th thoracic vertebral body. Grossly, a dislocation of the 6th thoracic vertebral body, resulting in spinal cord compression, was noticed. Although the etiology of the present incidence was unknown, it was suggested that a genetic factor played a role in the occurrence of this disease.
