Inherited causes of neurological conditions in ruminants

Question 1

Hydrocephalus

Answer 1

• Brain ventricle distension with fluid
  – Increased CSF production
  – Obstruction of outflow
  – Decreased CSF absorption
• Hereditary in some breeds
  – Holstein and Herefords (cattle)
  – Suffolk (sheep)
• Often seen alongside other congenital abnormalities
• Neonates often still born – prognosis is often poor if born alive, but some may reach slaughter if mildly affected

Question 2

Cerebellar hypoplasia and atrophy (cattle)

Answer 2

• Could be seen in any small ruminant but more commonly seen in cattle
• Commonly secondary to BVDv infection in utero (100-200 days gestation)
• Hereditary in some breeds (Hereford, Shorthorn, Ayrshire, Aberdeen Angus)
• Clinical signs vary from recumbency and opisthotonos to generalised ataxia with hypermetric gait
• No treatment available
• Prognosis depends on severity of clinical signs
• Not life threatening i.e. not important for life but will affect the gait of the animal
• Ultimately size of animal makes long term prognosis poor (dangerous to handle)

Question 3

Spastic paresis (Elso heel)

Answer 3

• Calves of most breeds
  – More commonly seen in Holsteins
  – Usually 1st seen from a few weeks old up to 6 months
  – Not very common generally (<1%) but some farms see quite a lot of cases (i.e. farms using a gene pool which has this)
• Very straight hocks, excess tone in gastrocnemius, ‘tin soldier’ gait, tail elevated -> usually one leg worse than other (or unilateral)
  – In BB calves quadriceps femoris is affected -> usually bilateral
• Long straight leg, when moving it will be swinging more from the hip than the stifle/hock
• Lameness becomes progressive until calf recumbent -> usually euthanised
• Treatment = partial tibial neurectomy (despite the issue not being with the tibial nerve, it innervates the muscles that are affected therefore will improve CS)

Question 4

Cerebellar hypoplasia and atrophy clinical signs

Answer 4

• Cerebellum important for fine motor movements
• So the animal will still be walking but smooth motor function is lost e.g. lots of wide gait, very shaky, unsteady on their feet
• Likely to get proprioceptive deficits as well
• Looks drunk