Bovine Eye Flashcards

1
Q

Give 3 primary diseases of the eye

A

New forest disease (infectious bovine kerato-conjunctivitis, ‘pink eye’)
Bovine iritis (silage eye)
Squamous cell carcinoma (cancer eye)

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2
Q

What causes New Forest Disease (infectious bovine kerato-conjunctivitis)?

A

Morexella bovis (gram -ve, transmitted by flies)
Also:
-Mycoplasma spp
-Pneumonia viruses etc

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3
Q

What is blepharospasm?

A

Abnormal contraction/twitch of eyelid

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4
Q

Give some clinical signs of New Forest Eye

A

Lacrimation
Blepharospasm
Early keratosis-white spot
Ulcer exposing Descemets membrane (could rupture -> remove eye), pannus
Healing ulcer -vascularisation, may have permanent scarring

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5
Q

How do you treat New Forest Eye?

A

LA eye ointment (cloxacillin)
Sub-conjunctival injection (ampicillin, amoxycillin, oxytetracycline etc, best on bulbar conjunctiva) (oxytet can be irritant so dilute with water)
Suture 3rd eyelid & eyelids or eyelids only
Eye patches

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6
Q

Give some risk factors for New Forest Eye

A
Flies (transmit moraxella)
Woodland
Dust
Chaff
UV light
(all of the above irritate the eye)
'Virus pneumonia'
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7
Q

Which season are you most likely to see New Forest Eye?

A

Summer (flies)

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8
Q

How can you prevent New Forest Eye?

A

Fly control- ear tags, pour ons, permethrins
Graze away from fly habitat (woodland)
Ventilation and fly control inside buildings
Vaccine-USA

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9
Q

What is Bovine Iritis associated with?

A

Big bale silage feeding

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10
Q

Which season is Bovine Iritis seen in?

A

Winter

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11
Q

Give the clinical signs of Bovine Iritis

A

Early cases: constricted pupil
Patchy/multiple areas of corneal opacity
Glaucoma
White flocules in anterior chamber
Later: vascularisation (inside surface of cornea)
Negative to fluorescein staining cf New Forest Disease
Eye may bulge, may get secondary keratitis

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12
Q

Bovine Iritis is a disease of which part of the eye?

A

Intenal cornea

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13
Q

Give some causes of Bovine Iritis

A

Unknown
Hypersensitivity reaction?
Link with Listeria?
Form of uveitis

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14
Q

How do you treat Bovine Iritis?

A

Antibiotics are ineffective
Sub-conjunctival (bulbar) injection of:
-Atropine (5mg) to dilate the pupil
-With dexamethasone (1-3mg) steroid

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15
Q

What size needle would you use for a sub-bulbar conjunctival injection?

A

22G (pale blue)
Use LA first
Hold head up and rotate for easy access

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16
Q

Which breed is predisposed to squamous cell carcinoma?

A

Herefords (white-faced)

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17
Q

When suturing eyelids together, what should you not do?

A

Suture through the conjunctiva- irritant

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18
Q

Give some risk factors for squamous cell carcinoma

A

White faces
>5 years old
UV exposure (Tropics)

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19
Q

Which parts of the eye does squamous cell carcinoma affect?

A

Cornea (can be invasive)
3rd eyelid
Conjunctiva

20
Q

How do you treat squamous cell carcinoma?

A

Can remove but may recur

21
Q

What can a foreign body in the eye lead to?

A

Keratitis

22
Q

What is keratitis?

A

Inflammation of the cornea

23
Q

What causes Malignant Catarrhal Fever?

A

Ovine herpes virus 2 (doesn’t cause clinical disease in sheep)

24
Q

What is the prognosis for Malignant Catarrhal Fever?

A

Usually fatal

25
Q

Give the clinical signs of Malignant Catarrhal Fever

A

‘Head and eye form’ most common

  • Persistent pyrexia (41oC)
  • Depressed-encephalitis
  • Nasal and mouth erosions
  • Enlarged lymph nodes
  • Respiratory signs
  • Diarrhoea
26
Q

How can you diagnose Malignant Catarrhal Fever?

A

ELISA

27
Q

Give the secondary eye lesions seen with Malignant Catarrhal Fever

A
  • Conjuntivitis
  • Eyelid oedema
  • Blepharospasm
  • Corneal opacity
28
Q

When are herpes viruses typically secreted?

A

During times of stress (lie latent in trigeminal ganglion)

29
Q

How do you diagnose infectious bovine rhinotracheitis (BHV 1)?

A

ELISA

30
Q

How do you prevent infectious bovine rhinotracheitis (BHV 1)?

A

Intra-nasal vaccines

31
Q

Give the clinical signs of infectious bovine rhinotracheitis (BHV 1)?

A

Pyrexia (41oC)
Conjunctivitis and serous discharge (red eye)
Corneal oedema
Nasal lesions & discharge

32
Q

How does listeriosis infect cows?

A

Infection via CNV or VII to brain via teeth

33
Q

Give the clinical signs of listeriosis

A
  • Septicaemia form in sheep -> die
  • Encephalitis more common (micro-abscesses in brain)
  • Circling disease, unilateral facial paralysis (droopy ear), depressed, positive reaction to menace test as can still see but can’t feel face if you poke with needle
  • Facial paralysis -> dry eye keratosis
34
Q

How do you treat dry eye keratosis?

A

High doses of penicillin or oxytetracycline

35
Q

Give some generalised diseases in which eye lesions may feature

A
  • BVD-cataracts, micropthalmia (infection between day 120-150 of pregnancy)
  • Septicaemia-hypopyon (pus in eye, calves), petechiae
  • Endotoxaemia-injected conjunctiva, petechiae
  • Dehydration-sunken eye
36
Q

Poisoning with what can result in blood in the anterior chamber (hyphaema)?

A

Bracken

37
Q

Which conditions can cause blindness?

A
  • Cerebro cortical necrosis
  • Lead poisoning
  • Vit A deficiency
  • Twin lamb disease (sheep)
38
Q

Cerebro-cortical necrosis is seen in which cattle?

A

Young growing cattle
Thiaminase production in rumen (ie lack of thiamine)
High energy diet

39
Q

How do you diagnose cerebro-cortical necrosis?

A

PM (brain changes, parts of brain fluoresce under UV light)

40
Q

How do you treat cerebro-cortical necrosis?

A

IV thiamine (vitamin B1) every 4 hours (inject slowly)

41
Q

What are the clinical signs of cerebro-cortical necrosis?

A
  • Star-gazing (early cases)
  • Negative menace response (blind)
  • Positive pupillary response to light
  • Nystagmus and convulsions
  • Opistothonus
42
Q

Give the clinical signs of lead poisoning

A
  • Negative menace test (blind)
  • Dilated pupils
  • Tremors and convulsions
43
Q

How do you treat lead poisoning?

A

Calcium versenate (chelating agent) iv and sedation

44
Q

How do you diagnose lead poisoning?

A

Pb in kidney, history

45
Q

Vitamin A deficiency typically affects which cows?

A

Growing cattle kept indoors

Fed root and straw diet

46
Q

Give the clinical signs of Vitamin A deficiency

A
  • Night blindness
  • Negative menace test
  • Dilated pupils
  • Oedema of optic disk
  • Can also have skeletal abnormalities