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


CONCLUSIONS
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.
Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Private Bag 11222, Palmerston North, New Zealand. gorbell@vetmed.wsu.edu
G M B
GM
Orbell
K G
KG
Thompson
M C
MC
Owen
J S
JS
Munday
D M
DM
West
D000818:Animals; D002574:Cervical Vertebrae; D015994:Incidence; D007403:Intervertebral Disc / Q000000981:diagnostic imaging / Q000473:pathology; D008159:Lumbar Vertebrae; D008297:Male; D009520:New Zealand / Q000453:epidemiology; D010865:Pilot Projects; D011859:Radiography; D012720:Severity of Illness Index; D012756:Sheep; D012757:Sheep Diseases / Q000453:epidemiology / Q000473:pathology*; D013122:Spinal Diseases / Q000453:epidemiology / Q000473:pathology / Q000662:veterinary; D013128:Spinal Osteophytosis / Q000453:epidemiology / Q000473:pathology / Q000662:veterinary*