Bovine Neuro DDX

Question 1

cerebrocortical necrosis ( lights up under UV light necropsy )

Answer 1

Dx: Polioencephalomalacia

2 most common causes

1. low thiamine ( thiamine analog - amprolium , low intake )
2. high sulfur ( high - molasses urea diet, corn or sugar cane byproducts, water, plants (alfalfa, Canada thistle, kochia, lambs quarter)

** central blindness ( no menace with normal PLRs) and dorsomedial strabismus (stargazing)

Question 2

Bovine Spongiform Encephalopathy (BSE)

** REPORTABLE **

Answer 2

• slow, chronic disease caused by PRION
• CS: - insidious onset of abnormal behavior
  - initially subtle–> hyperesthesia, nervousness, aggression, low head carriage, hypermetria, ataxia, tremors

** associated with variant form of (Creutzfeld Jacob disease) in humans

Question 3

“Bovine bonkers”

Answer 3

Dx: Non-protein-nitrogen toxicity ( or ammoniated feed toxicity )

Source ( urea ) : ammoniated high quality feed, molasses licks, protein tub supplements

** toxin = 4-methylimidazole ( no antidote, just supportive care for tx)

CS - high rumen pH and smell of ammonia
- odd behaviors

Question 4

” tetany, convulsions, acute death” ddx

Answer 4

• 1. hypo magnesium tetany ( grass tetany) –> BUT more common in LACTATING females
• 2. Non-protein-nitrogen toxicity
• -> BUT in post- calf weaning (dry) cows