Unusual skeletal deformities in calves in a Saskatchewan beef herd.

A very high incidence of posterior paresis in growing calves was casued by abnormal development of the vertebral column. The pathological changes were focal premature synostoses of vertebral growth plates with resulting reduction in size of the vertebral canal. Malacic changes were seen in sections from all areas of the spinal cord. Abnormalities in growth of the cranium and appendicular skeleton were also present. The growth plates in the cranial base were prematurely closed and the cranial cavity was shortened. Long bones were shortened and distorted. Possible causes include teratogenic plants or chemicals, mineral deficiencies, and hypervitaminosis A.