Pink Eye and SSC Flashcards
What are the major diseases of the bovine eye?
Infectious: Infectious Bovine Keratoconjunctivitis (IBK) - pink eye, squamous cell carcinoma and trauma or foreign body
Where is the ulcer on a cow with trauma or a foreign body?
Not central! (Pink eye central) - see best with stain
Why does the producer care about IBK?
Can’t see to reproduce or eat and grow (decreased weaning weight)
Is IBK painful?
Yes!
What are other cost associated with IBK?
Decreased milk production, less growth of calves, sale discounts due to scaring, decreased value of breeding stock, treatment cost, prevention cost and welfare of animal
What is the primary pathogen in IBK?
Moraxella bovis and boviculi - pili, attach to cornea, local persistance, sytotoxins, epithelial cell lysis and pore in cornea (ulcer), lysis of neutrophils release enzymes, damage phospholipids
Can cattle be a carrier of Mycoplasma Bovis?
Yes
What environmental factors help increase pathogenicity of pink eye?
UV damage, dust, plant material and feeds, female face flies
What kind of cows are predisposed?
Herefords and Holstein (white around eyes make UV damage worse)
What are other risk factors for IBK?
Summer or Winter (heat and flies or feeding practices/confinement/snow)
Age - calves more likely than cows
Nutritional deficiencies- protein, energy, vitamin A, copper and selenium
Bos taurus more likely (Hereford and baldies)
What are the clinical signs of pink eye?
Scleral injection
Epiperoa (tearing)
blasospasms (blinking)
Corneal Edema
Central corneal ulcer (not scar)
neovascularization
Photophobia
Do you need to treat a scar? What does it look like?
No, it is not raised, shiny has a tear film over it and no other signs (tearing or blinking)
What are some sequelae to pink eye?
Glaucoma
Bupthalmos
Blindness
How effective are pink eye vaccines?
Not very but anything you can do can help (environmental control of flies best first step though)
-Autogenous best (culture cow on farm and use that strand) - need 150 dose minimum filled
What is IBK treament?
Bulbar scleral injections of 1-2ml of penicillin procaine G and 0.5-1ml Dexamethasone
What drugs are labeled for pink eye?
Oxytetracyline, Draxxin
Extralabel drugs for pink eye?
Nuflor, Excede
What are some prevention strategies?
Fly control, pasture management (weed and bushog), feed management and UV protection
What are some other infectious etiologies with ocular manifestations?
Mycoplasma (conjunctivitis), IBR (conjunctivitis, edema, neovascular), Malignant Catarrhal Fever, Listeriosis, BVD, Neonatal Septicemia
What kind of neoplasia likes the eye?
Squamous cell carcinoma
Lymphoma can cause exophthalmia
What is cancer eye?
Squamous cell carcinoma
What is a leading cause of whole carcass condemnation in US?
Cancer eye (treat, decrease production or early culling)
Where does SCC like to be?
Conjunctive, Corneosclearl junciton, nicitating membrane, cornea and eyelid
What are risk factors for SCC?
Older, UV light, Breed (white faced), genetics
Might there be a viral component to SCC?
Herpes?
Diagnosis of Cancer Eye?
Epiphora
Blephorospasms
Breed or white face
(examine white face cattles eye once a year)
Assess depth invasion
How do you decide whether to treat or cull?
Based on the stage (1-4) and location
Where is SCC more aggressive when found in that location?
Nictitating membrane and lower eyelid
By what stage is SCC most likely in the lymph nodes and will cause whole carcass condemnation?
Stage 4
If you have stage 1-3 (plaques, keratoma, papilloma) they are benign, but will they eventually progress? How do you treat?
Yes
Remove it surgically 90% cure, 45% recurrence (keratectomy, 3rd eyelid removal, papilloma removal, exenteration, cryotherapy, hyperthemia
Why would you treat SSC?
Prolong life of heavy bred animal or to help get young calf grown
What’s the difference between enucleation and exenteation?
Enucleation: infection of the globe, glaucoma, globe rupture (traumatic or secondary)
Exenteation: ocular neoplasia, SCC>2.5cm, retrobulbar lymphosarcoma
How do you do enucleartion?
Restrain, sedate, pain meds, antibiotic, clip and suture closed
