CNS disease in cattle

Question 1

What does hyperaethetic mean

Answer 1

Hyper responsive to stimuli

Question 2

What does obtunation mean

Answer 2

No response to normal stimuli levels

Question 3

What does stupor mean

Answer 3

Respond only to painful stimuli

Question 4

What does coma mean

Answer 4

No reponse to ANY stimuli

Question 5

Two spots where we can take a CSF tap

Answer 5

Cisterna magna and lumbosacral space

Question 6

How does lesion affect limb responses based on position

Answer 6

When cranial to limb get hyperactive reflexes (+ataxia and weakness)

When level with limb = depressed reflexes + ataxia and weakness

When caudal to limb = no effect on limb

Question 7

What clinical signs do forebrain lesions give

Answer 7

seizures, behavioural changes, propulsive pacing, circling, aggression, charging, mania, excessive licking

Question 8

What clinical sign does cerebral disorders give

Answer 8

apparent blindness; but still have normal pupillary light reflex

Question 9

What is hydrocephalus

Answer 9

Congenital condition where calves are born with domed forehead
- May relate to VIt A deficiency, Schmallenberg

Question 10

What is hydrancephaly

Answer 10

‘Dummy syndrome’ in calves; born without brain hemispheres in skull
- Due to viral infection in utero; BVDv, bluetongue, Schmallenberg

Question 11

What in utero viral infection is most associated with cerebellar hypoplasia (intention tremors, ataxia, dymetria)

Answer 11

Bovine viral diarrhoea virus

Question 12

What brain inflammatory condition can bull rings be associated with

Answer 12

Pituitary infections

Question 13

When we get embolic spread of from distant abscesses/septicaemia to brain what form abscesses; what organism do we commonly isolate from it

Answer 13

Trueperella

Question 14

What does listeriosis in calves look like

Answer 14

Facial cranial nerve deficits; drooped ear/eyelids, strabismus, nystagmus, loss of sensation

> On PM see microabscesses in pons and medulla

Question 15

What might be a common route of brain infection with listeria in calves

Answer 15

Via oral route (from low quality silage); via cuts in mouth e.g due to cheek teeth

Question 16

What are notifiable neurological diseases

Answer 16

Rabies (classical)
Aujesky’s diseases = pseudorabies/mad itch = a pig herpes virus
BSE

Question 17

What is the causative agent in thromboembolic meningoencephalitis

Answer 17

Histophilus somni
> NB respiratory disease more common than neurological

Question 18

What brain condition can lack of thiamine cause in cattle

Answer 18

Cerebrocortical necrosis

Question 19

What is an unusual finding in cerebrocortical necrosis (from thiamine deficiency)

Answer 19

Cut surface of the brain fluoresces

Question 20

How might we treat lead poisoning

Answer 20

Rumenotomy to remove lead material
Chelation therapy i.e using calcium EDTA

Question 21

What brain condition can salt poisoning cause

Answer 21

Cerebral oedema

Question 22

How might a cow suffering from cerebrocortical necrosis present

Answer 22

Recumbant and comatose
Cortical blindness, paddling movements, head pressing, nystagmus etc

Question 23

What is nervous ketosis

Answer 23

= neurological manifestation of ketosis; see high excitability, apparent blindness, head pressing

Treat via IV glucose

Question 24

What is ‘night blindness’ a sign of

Answer 24

Vitamin A deficiency

Question 25

In what vitamin deficiency might we see retinal bleeding

Answer 25

Vitamin A

Question 26

What is hepatic encephalopathy

Answer 26

Where we see changes in behaviour and seizures in cows; because diffuse liver damage has cause hyperammonaemia and other toxic factor accumulation

Question 27

Signs of botulism in cattle; and what is common source of contamination

Answer 27

> Flaccid paralysis, sternal recumbency, hind limb ataxia, loss of tail tone

Associated with contamination of feed with dead rodents or the use of poultry with chicken carcasses in it as manure

Question 28

In what situations might we see tetanus in cattle

Answer 28

With deep, anaerobic puncture wounds e.g from castration or dehorning
Or ruminal damage from fibrous feeds

Question 29

Which viral diseases can cause cerebellar hypoplasia in neonates

Answer 29

Bovine viral diarrhoea virus
Bluetongue virus
Schmallenberg virus

Question 30

What diet change would encourage more thiaminase producing ruminal bacteria and therefore more risk of cerebrocoritcal necrosis

Answer 30

High carbohydrate diet

Question 31

Why does thiamine deficiency lead to cerebrocortical necrosis

Answer 31

Because it is a co-enzyme in carbohydrate metabolism
- SO deficiency leads to lower glucose
-> NEURONS NEED GLUCOSE

Without energy in brain: get failure of Na+ and H2O transport; get cerebrocortical oedema, raised intracranial pressure, lower blood flow and necrosis

Question 32

How does lead poisoning cause cerebral lesions

Answer 32

Because lead binds to sulfhydryl groups on enzymes, including those involved in carbohydrate metabolism
- Get fall in energy metabolism + effects on endothelial cells

Oedema and raised ICP –> lower blood flow and ischaemia

Question 33

Why do we see cerebro-cortical necrosis (distribution) in thiamine deficiency

Answer 33

Because these are the neurons which are most susceptible to energy impairment so die first

Question 34

Which bacteria is classically associated with haematogenous spread to brain and infectious thrombo-embolic meningoencephalitis

Answer 34

Histophilus somni

Question 35

How does listeria reach the brain

Answer 35

Ascneding infection via nerves

Question 36

What is typical histopathology for viral encephalitis

Answer 36

Perivascular cuffing with lymphocytes
Vasculitis
Cell death
Lesions usually diffuse

Question 37

What rare CNS condition can neospora caninum cause in cattle

Answer 37

Degeneration of the spinal cord; following in utero infection