DS: Farm Animal Opthalmology Flashcards
1
Q
What pathogens may cause opthalmolgical problems in cattle?
A
Viruss
2
Q
How do viruses affect cattle? Which virsus affect cattle?
A
- transplacental infection of foetus @ d125-175 of gestation
- final stages of organogenesis of nervous sytem
- development of foetal immune system
> IBR, OHV2
3
Q
How may IBR affect cattle?
A
> IBR
- retinal atrophy, optic neuritis, cataract and micropthalmia with retinal dysplasia
- often -> blindness
- affects URT -> “red nose” and eyes
- conjunctivitis (hyperaemia and oedema (chemosis) +- diffuse corneal oedema too)
- usually present as bilateral serous ocular discharge
4
Q
Tx of IBR in cattle?
A
- symptomatic
- prevention with vax and biosecurity
5
Q
Which species does ovine herpes virus 2 affect?
A
Cattle (transmitted from sheep - cattle)
6
Q
Clinicla signs of OHV2?
A
- GI: anorexia, D+
- agalactia
- pyrexia >41*
- RT signs (mucopurulent nasal discharge, severe dyspnoea with stertor d/t nasal cavity exudate, ^ LNs)
- ocular signs (opacity of cornea, unilateral progressing to bilateral, hypopyon may develop but often die first)
7
Q
Dx of OHV2?
A
- viral DNA by PCR
- frequently advise PTS
8
Q
Which bacteria may affect cattle optalmologically?
A
- Moraxella Bovis (New Forest Eye, Pink Eye) G- aerobe also found in many recovered and apparently normal cattle
- Listeria Monocytogenes (Silage eye) G+ microaerophilic bacteria found in poorly fermented silage
9
Q
Outline pathophysiology of Moraxella bovis
A
- multifactorial dz
- cattle carriers
- fomites (flies, dust, long grass), commonly seen summer/early autumn
- tends to be UNIlateral
- tearing and photophobia, conjunctival hyperaemia and chemosis
- corneal changes may follow (oedema, ulceration, abscess may develop -> hypopyon)
- vision los within 3d
10
Q
Tx Moraxella bovis
A
- tx early to help resolve problem and help prevent spread
- claxacillin
- tetracycline
- bulbar conjunctival injection
- NOT topical steroids (corneal ulceration risk)
> isolate affected animals during tx and use fly control
11
Q
Pathophysiology of listeria monocytogenes?
A
- encephalitis and abortion
- CN deficits
- ocular clinical signs: strabismus and nystagmus
- can also present as SilageEye/Red Eye
- originates directly from silage (inoculated into eye)
12
Q
Dx listeria monocytongenes?
A
- tiem of year
- clinical signs
13
Q
Tx listeria monocytogenes
A
- Abx, chlortetracycline or penicillin
- given in early stages (IM/SC)
- NSAIDs to reduce inflam
14
Q
Which neoplasia commonly affects cattle?
A
> SCC
- malignant neoplasma
- > 5yo
- low pigment = pdf (Herefords with white heads, actinic radiation from the sun)
15
Q
Outline lesion stages of SCC
A
- plaque (hyperplastic epithelium)
- papilloma (not malignant, high regression rate)
- SCC in situ (non-invasive)
- invasive SCC (past epithlium’s lamina propria)
