Neuroaxonal dystrophy in Merino-Border Leicester × Polled Dorset lambs

Area of Science:

• Veterinary Pathology
• Animal Neurology
• Sheep Diseases

Background:

• Neuroaxonal dystrophy (NAD) is a debilitating neurological condition affecting various animal species.
• Ovine NAD cases are typically reported in older animals with less severe myelin pathology.
• Understanding NAD in different breeds and age groups is crucial for diagnosis and management.

Observation:

• Two young crossbred lambs (Merino-Border Leicester × Polled Dorset) presented with severe ataxia and listlessness.
• Clinicopathological examination revealed numerous axonal swellings (spheroids) in the central nervous system.
• Severe spinal cord demyelination was a prominent feature in both affected lambs.

Findings:

• This study describes the first reported cases of NAD in this specific crossbred lamb population.
• Affected lambs were significantly younger than previously documented cases of ovine NAD.
• The observed myelin loss was considerably more extensive than reported in prior studies of ovine NAD.

Implications:

• These findings expand the known spectrum of NAD presentation in sheep.
• The early onset and severity suggest potential genetic or environmental factors unique to this population.
• Further research into the pathogenesis of NAD in young lambs is warranted.