Severity and distribution of ventral thoracolumbar spondylosis and histological assessment of associated intervertebral disc degeneration in cull rams

Authors: Owen MC, Thompson KG, Munday JS, Orbell GMB, West DM
Publication: New Zealand Veterinary Journal, Volume 55, Issue 6, pp 297-301, Dec 2007
Publisher: Taylor and Francis

Animal type: Livestock, Production animal, Ruminant, Sheep
Subject Terms: Biosecurity, Skeletal/bone/cartilage, Disease surveillance, Locomotor, Nervous system/neurology, Pathology, Disease/defect
Article class: Scientific Article

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Abstract: AIM: To conduct a pilot study investigating the incidence and pathology of spondylosis in a sample of cull rams in New Zealand.
METHODS: Vertebral columns from 51 cull rams from different properties were assessed radiographically for evidence of spondylosis. They were graded according to severity, using a four-point grading system. Samples of intervertebral discs representing different grades of spondylosis were examined histopathologically.
RESULTS: Forty (78%) rams had spondylosis in at least one intervertebral space. Of these, 11 had ankylosis involving one or more intervertebral spaces. The frequency of spondylosis was greater in the thoracic than lumbar region (p<0.001), and was most frequent between T10–T11. Histopathological examination of intervertebral discs associated with all grades of spondylosis revealed degenerative changes in the annulus fibrosis.
CONCLUSIONS: Spondylosis appeared to be common in cull rams and affected thoracic and lumbar vertebrae. It often involved ankylosis of adjacent vertebrae, and was associated with degeneration of the intervertebral disc.
CLINICAL RELEVANCE: Spondylosis may reduce the serving ability of rams and be an important underlying reason for culling. The pathogenesis of spondylosis is unknown but may involve high mating frequencies during the breeding season.
KEY WORDS: Ovine, ram, vertebrae, spondylosis, ankylosis, annulus fibrosis

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