Bovine ophthalmics

Question 1

what block can be used to prevent the eye closing for examination?

Answer 1

auriculopalpebral (motor)

Question 2

what can be used to locally block the cows eye for examination if painful?

Answer 2

amethocaine

Question 3

what are the main primary eye diseases of cattle?

Answer 3

infectious bovine kerato-conjunctivits (new forest eye)
bovine iritis (silage eye)
squamous cell carcinoma

Question 4

what is bovine iritis more commonly known as?

Answer 4

silage eye

Question 5

what is infectious bovine kerato-conjunctivitis more commonly known as?

Answer 5

new forest eye

Question 6

what pathogen causes new forest eye (IBK)?

Answer 6

Morexella bovis
(sometimes Mycoplasma spp)

Question 7

what are the clinical signs of new forest eye (IBK)?

Answer 7

lachrymation
blepharospasm
early keratitis (white spot)
ulceration
pannus

Question 8

how would early keratitis present?

Answer 8

slight white spot on the conjunctiva

Question 9

what are possible treatments for new forest eye (IBK)?

Answer 9

LA eye ointment
subconjunctival injection
suture eyelids closed

Question 10

what is the antibiotic in LA eye ointment for treating new forest eye (IBK)?

Answer 10

cloxacillin based

Question 11

how often do you have to administer cloxacillin based eye ointment for new forest eye (IBK)?

Answer 11

every other day

Question 12

what antibiotic can be used as a subconjunctival injection to treat new forest eye (IBK)?

Answer 12

oxytetracycline or amoxicillin

Question 13

what are the risk factors for getting new forest eye (IBK)?

Answer 13

flies (and their habitats… woodlands)
dust/chaff
UV light

Question 14

how can new forest eye (IBK) be prevented?

Answer 14

fly control (tags, permethrin, pour-ons)
graze away from fly habitats
ventilation/fly control

Question 15

what is the pathogenesis of bovine iritis (silage eye)?

Answer 15

immune reaction to antigens of Listeria

Question 16

what are the clinical signs of bovine iritis (silage eye)?

Answer 16

constricted pupils
corneal opacity
glaucoma
white floccules in anterior chamber
vascularisation inside cornea

Question 17

what is the early clinical sign of bovine iritis (silage eye)?

Answer 17

constricted pupils

Question 18

do animals with bovine iritis (silage eye) have flu rosin take up?

Answer 18

no, as there is no damage to the cornea

Question 19

how is bovine iritis (silage eye) treated?

Answer 19

antibiotics alone are ineffective
subconjunctival injection atropine and dexamethasone

Question 20

why is atropine injected subconjunctival in bovine iritis (silage eye) cases?

Answer 20

is a mydriatic so opens the drainage angle of the eye

Question 21

why is dexamethasone given in bovine iritis (silage eye)?

Answer 21

is an immune suppressant to suppress the hyersensitisation

Question 22

what breed is predisposed to squamous cell carcinomas?

Answer 22

herefords

Question 23

in terms of eyelid margins, what should you keep in mind when dealing with trauma?

Answer 23

need to keep the eyelid margins, possible risk of recurrent infections if animal can’t close eye/blink properly

Question 24

what are some possible diseases that can cause secondary eye issues?

Answer 24

malignant catarrhal fever

Question 25

what is the main risk factors of cattle getting malignant catarrhal fever?

Answer 25

grazing with sheep

Question 26

why is grazing with sheep a risk factor for cattle developing malignant catarrhal fever?

Answer 26

caused by ovine herpes virus 2

Question 27

what are the clinical signs of malignant catarrhal fever?

Answer 27

persistant pyrexia (41°C) depressed (encephalitis) nasal/mouth erosions lymph node enlargement respiratory signs diarrhoea

Question 28

what is the pathogenesis of malignant catarrhal fever?

Answer 28

immune mediated vasculitis

Question 29

what are the eye lesions associated with malignant catarrhal fever?

Answer 29

conjunctivitis eyelid oedema blepharospasm corneal opacity (starts on the edge)

Question 30

what pathogen causes infectious bovine rhinotracheitis?

Answer 30

bovine herpes virus 1

Question 31

why can IBR recrudesce?

Answer 31

because it lies latent in trigeminal ganglia, recrudesces at times of stress

Question 32

is a vaccine available for IBR?

Answer 32

yes, marker vaccine is available

Question 33

what are the clinical signs of IBR?

Answer 33

pyrexia (41°C) conjunctivitis and serous discharge corneal oedema nasal lesions/discharge severe milk drop abortions

Question 34

what are the clinical signs of listeriosis?

Answer 34

encephalitis circling disease unilateral facial paralysis

Question 35

how is listeriosis treated?

Answer 35

oxytetracycline or penicillins (good outcome if caught before circling/depression starts)

Question 36

why does listeriosis cause keratitis of the eye?

Answer 36

paralysis of the face beens they are unable to blink leading to dry eye and keratitis

Question 37

what is a possible disease in cattle that can cause cataracts?

Answer 37

BVD (infected around day 100 of pregnancy)

Question 38

what effect does septicaemia have on the eye?

Answer 38

hypopyon

Question 39

what effect does bracken poisoning have on the eye?

Answer 39

blood in anterior chamber (due to thrombocytopenia)

Question 40

what are some possible diseases that can cause blindness?

Answer 40

CCN lead poisoning vitamin A deficiency twin lamb disease

Question 41

what causes CCN?

Answer 41

thiamine (B1 deficiency) in young growing animals

Question 42

what are the clinical signs of CCN?

Answer 42

star gazing negative menace positive pupillary light response nystagmus convulsions opisthotonus

Question 43

what can be done to treat CCN?

Answer 43

(depends on duration of brain swelling and the damage caused by it) thiamine IV diet change

Question 44

how can lead poisoning be treated?

Answer 44

IV sodium calcium edetate (EDTA)

Question 45

what effect does vitamin A deficiency have on the eye?

Answer 45

oedema of optic disc causing blindness (more during night)