Traumatic causes of neurological conditions in ruminants

Question 1

Obturator nerve injury: tx

Answer 1

• Manage conservatively
• NSAIDs (for concurrent injuries)
• Deep bed
• Hobbles/shackles (maintain medial positioning of hindlimbs)

Question 2

Obturator nerve injury

Answer 2

• Commonly related to calving
  – Large calves
  – Hip-locked calves
• Hindlimb adductor muscle paralysis
  – ‘splits’
• Direct trauma to nerve or localised ischaemia secondary to pressure from calf

Question 3

Obturator nerve injury: prognosis

Answer 3

• Prognosis is good in most cases
• Full recovery can take several months
• Tearing/transection of nerve = poor prognosis

Question 4

Sciatic nerve injury

Answer 4

• Post-calving (typically dairy cows) and iatrogenic (typically calves and small ruminants)
• Difficulty standing
• Dropped hock with knuckled fetlock
  – Bilateral or unilateral
  – Characteristic leg position is diagnostic

Question 5

Sciatic nerve injury: tx

Answer 5

• NSAIDs
• Supportive care

Question 6

Sciatic nerve injury: prognosis

Answer 6

• Prognosis is good, esp if only 1 leg affected
• Recumbency associated with poorer prognosis
• Recovery in a few days up to several weeks

Question 7

Tibial nerve injury

Answer 7

• Sciatic runs caudal thigh and branches just before stifle
  – Tibial branch -> caudal branch innervates hock extensors and digit flexors plus sensation to caudal distal hindlimb
  – Peroneal (common fibular) branch -> cranial branch innervates hock flexors and digit extensors plus sensation to cranial distal hindlimb
• Injury to tibial nerve also presents with dropped hock but fetlock hyper-extended (cows walk on heels)
• Rare compared to sciatic injury
  – Occurs secondary to injury of medial hindlimb in hock region

Question 8

Femoral nerve injury (calves)

Answer 8

• Calves
• Calves injured during birth
  – Associated with excessive traction, especially if hip-locked
• Calves are unable to extend stifle or bear weight on affected limb
• Bilaterally affected calves cannot stand (dog sit)
• Quadriceps femoris atrophies over approx. 10 days
• Patellar laxity also develops
• Treatment is conservative -> remember to ensure adequate nutrition (i.e. ensure they can suckle)
• Prognosis is dependent on severity of clinical signs

Question 9

Brachial plexus injury

Answer 9

• Rare
• Calves: birth injuries
  – Associated with excessive traction on forelimbs - especially if cow goes down with calf half-way delivered
• Sheep: accidents (stuck in fence/gate) or harness injuries (rams)
• Inability to extend elbow, carpus or fetlock
• Dropped elbow, scuffed hoof, knuckled foot when resting
• Unable to bear weight on affected limb in severe cases
• Shoulder muscles atrophy
• Scapular spine becomes prominent
• Treatment is conservative
• Can splint forelimbs of calves to aid movement and prevent tendon contracture

Question 10

Radial nerve injury

Answer 10

• Occurs following prolonged lateral recumbency or traumatic injuries
• Knuckling of carpus and fetlock but can still weightbear
• Decreased sensation of antebrachium, metacarpus and foot
• Conservative treatment
• Prognosis depends on severity of injury