Disorders of the Bovine eye Flashcards
If an ulcer extends all the way to the sclera, what is the likely etiology?
Trauma/Foreign body
What is the main infectious eye condition that is worried about in cattle?
Infectious bovine keratoconjunctivitis
What are some other infectious causes of eye lesions in cattle?
Infectious bovine rhinotracheitis conjunctivitis, malignant catarrhal fever keratoconjunctivitis, listeriosis, bovine viral diarrhea, ocular signs of neonatal septicemia
Why is pinkeye such an economically important condition of cattle?
It results in significantly lower weaning weights (about 20 lbs) as calves spend less time eating due to pain
What other costs are associated with pinkeye in cattle?
Decreased milk production in cows, sale discounts due to scarring, decreased value of breeding stock, treatment costs, prevention costs, welfare costs
Are there any long term effects of pinkeye after resolution?
Yes, decreased muscle area and fat thickness even at a year old
What bacteria is responsible for pinkeye?
Moraxella bovis, Moraxella boviculi may be a secondary invader
Name some of the features that increase pathogenicity of moraxella bovis
Pilli (Q enhances attachment of bacteria to corneal cells, I enhances local persistence and establishment of infection), cytotoxins (beta hemolytic, corneotoxic, leukotoxic, hydrolytic/proteolytic) which cause pore to form through cornea
What two concurrent infections can lead to significantly more damage in pinkeye cases?
Mycoplasma, infectious bovine rhinotracheitis
How are most cattle affected by pinkeye?
Carrier animals
What can cause the corneal irritation that assists bacteria in entering the eye?
UV damage to the cornea, scarification by dust, plant material, feeds, female face fly
During what season are pinkeye infections most common?
Summer > Spring/Fall > Winter
What nutritional deficiencies may contribute to severity of pinkeye infections?
Protein and energy, vitamin A, copper and selenium
What are the main clinical signs associated with pinkeye infections?
Scleral injection, corneal edema, central corneal ulcer, excessive lacrimation, neovascularization, photophobia/blepherospasm
How will the eye look different long term after pinkeye infection?
there will always be a scar present, may get better over time
What are some occasional sequele to pinkeye?
Secondary glaucoma with bupthalmos (trt-drain anterior chamber and let lens fall out), blindness
What type of vaccine is the m bovis vaccine? Is it effective?
Killed Bacterin and autogenous vaccine
- none are proven effective
What are the treatment options for pinkeye?
Topical- often not practical
Bulbar scleral injections- penicillin procaine G +/- dexamethasone
What drugs are labeled for systemic use in pinkeye cases?
Oxytet 200 SQ
Draxxin SQ
What extralabel uses of drugs is commonly used for pinkeye cases?
Nuflor, excede
-both show evidence at reducing ulcer healing time
What practices can be implemented to help protect against pinkeye?
Fly control (pour ons, spraying, fly tags), pasture management (bush hogging, weed control), feeding management (keeping hay from being fed where cattle are allowed to “dig”), UV protection (provide shade)
What ocular sign does mycoplasma cause?
conjunctivitis
What ocular sign does infectious bovine rhinotracheitis cause?
conjunctivitis, ocular discharge, corneal edema, neovascularization
What ocular sign does malignant catarrhal fever cause?
photophobia, epiphora, episcleral injection and scleritis, conjunctivitis, keratitis with edema and neovascularization, anterior uveitis, exopthalmia
