Uveitis in Cows

Uveitis means inflammation of the uvea, the vascular middle layer of the eye that includes the iris, ciliary body, and choroid. In cattle, the problem is usually most obvious in the front part of the eye, where pet parents and producers may notice squinting, tearing, a painful-looking eye, or a cloudy blue haze over the cornea.

This is not a single disease. It is a clinical problem with many possible triggers. In cows, uveitis may occur with infectious bovine keratoconjunctivitis (pinkeye), eye trauma, severe corneal disease, malignant catarrhal fever, photosensitization-related irritation, or less commonly with deeper systemic illness. Because several eye conditions can look similar from a distance, a hands-on exam by your vet is important.

Uveitis deserves attention because inflammation inside the eye can become self-sustaining. If it is not controlled early, the eye may develop scarring, synechiae (adhesions), cataract, glaucoma, or lasting vision loss. Some cows recover well with timely care, while others need repeated treatment and monitoring.

In cattle, uveitis is often secondary, meaning another eye or body problem triggers inflammation inside the eye. One of the most common practical causes is severe infectious bovine keratoconjunctivitis (IBK, or pinkeye). Corneal ulceration and surface inflammation can trigger reflex uveitis, making the eye more painful and cloudy. Trauma from hay stems, dust, plant material, or foreign bodies can do the same.

Less common but important causes include systemic infectious disease. Merck notes that in bovine malignant catarrhal fever, primary uveitis with associated keratitis can occur. Your vet may also consider systemic illness, septic processes, or less common infectious causes depending on the cow's age, herd history, vaccination status, and whether other signs such as fever, oral lesions, nasal discharge, or neurologic changes are present.

Environmental and management factors matter too. Heavy face fly pressure, UV light exposure, tall seed heads, and dusty conditions can all increase eye irritation and raise the risk of diseases that lead to uveitis. In some cases, photosensitization or plant-related irritation may also contribute. Because the list of causes is broad, treatment works best when your vet addresses both the eye inflammation and the underlying trigger.

Diagnosis starts with a careful history and physical exam. Your vet will want to know when the eye changed, whether one or both eyes are affected, if the cow has been rubbing the eye, and whether other cattle in the group have pinkeye or respiratory signs. Herd-level clues can be very helpful in cattle medicine.

A focused eye exam usually includes checking the cornea, conjunctiva, pupil size, and the clarity of the front chamber of the eye. Fluorescein stain helps identify corneal ulcers, which are common in cattle with pinkeye or trauma and can change which medications are safe to use. Tonometry may be used when available to measure eye pressure, because uveitis often lowers pressure while glaucoma raises it.

Depending on the case, your vet may also recommend a broader workup such as a CBC, serum chemistry, or herd-level infectious disease testing if systemic illness is suspected. The main goal is to distinguish uveitis from other urgent eye problems and to identify whether the inflammation is secondary to IBK, trauma, malignant catarrhal fever, or another condition. That distinction guides treatment choices, withdrawal planning, and prognosis.

Prevention focuses on reducing the problems that commonly trigger eye inflammation. In many herds, that means strong pinkeye prevention: lowering face fly pressure, reducing eye irritation from dust and seed heads, and separating or promptly treating affected cattle when practical. Cornell Integrated Pest Management notes that face flies spread pinkeye and recommends targeted control rather than blanket insecticide use, along with monitoring fly numbers and using practical tools such as face rubbers, dusters, traps, and shelter.

Pasture and housing management also matter. Mow or manage tall, stemmy forage that can scratch eyes, improve ventilation in dusty areas, and provide shade where possible during periods of intense sunlight. Good nutrition and overall herd health support eye resilience, and vaccination plans for pinkeye-related pathogens may be worth discussing with your vet in herds with recurring seasonal disease.

Finally, make eye checks part of routine observation. Early cases are easier to treat and less likely to progress to severe pain or vision loss. If you notice tearing, squinting, or a cloudy eye in one cow, check the rest of the group and contact your vet early so the herd plan can match the likely cause.