Compressive cervical myelopathy in young Texel and Beltex sheep.

BACKGROUND

This investigation was prompted by the referral of increasing numbers of young Texel and Beltex rams with ataxia and weakness, or wobbler syndrome.

OBJECTIVE

The study aims were to describe the clinical and pathologic findings in affected sheep.

METHODS

The animals evaluated in this study included 7 Texel sheep (6 male and 1 female) and 3 Beltex sheep (2 male and 1 female) referred from pedigree flocks. Typically, the sheep were 15-18 months of age at referral.

METHODS

Diagnostic investigations included radiographic and computed tomographic (CT) myelography followed by gross postmortem and histopathologic examinations.

RESULTS

Clinical findings typical of cervical spinal cord compression were present in all sheep but varied in severity. Myelography confirmed dorsal spinal cord compression in the region of C6-C7. No bony abnormalities were identified as described in cases of canine and equine wobbler syndrome. Postmortem examinations revealed discrete, smooth, nodular to polypoid projections of adipose tissue apparently prolapsing through the dorsolateral intervertebral space at C6-C7 and causing localized spinal cord compression. Histopathology of the nodules confirmed that they were composed of well-differentiated adipocytes typical of fatty tissue. Spinal cord lesions were similar in all sheep with marked Wallerian degeneration at the site of compression and mild Wallerian degeneration present cranial and caudal to the lesion.

CONCLUSIONS

The findings of this study suggest a novel cervical myelopathy in these sheep breeds caused by the presence of fatty nodules encroaching into the dorsal vertebral canal at C6-C7. Additional investigations are required to establish the etiology and possible hereditary risk factors for this unique clinicopathologic syndrome.