Pinkeye (or infectious keratoconjunctivitis) is a scourge that most cattle operations will deal with at some point. Regardless of the type of cattle affected or time of year, prevention always beats treatment. But, as cattle producers and veterinarians quickly point out, preventive efforts directed toward this disease sometimes fail. Decisions then need to be made about treatment.
Pinkeye in this context refers to infections of the surface of the eye with bacteria such as Moraxella bovis. Since this is a bacterial infection, antibiotics are the hallmark of pinkeye treatment. Beyond that, what other considerations are there?
Producers contemplating pinkeye treatment should first have a conversation with their veterinarian. Most of the “wives’ tales” and home remedies for pinkeye have potential to do more harm than good. At the very least, run your plan past your veterinarian before trying something new.
Pinkeye Treatment: Four Aspects
Let’s consider four different aspects of pinkeye treatment. Prompt treatment of acute cases (eye is still tearing) is important to minimize long-term effects of chronic infections. Treating cattle with white spots (corneal scarring) but no active redness or tearing is not productive, as the active infection is not present anymore.
1. Systemic treatment
This involves injections (subcutaneous or intramuscular) of antibiotics, which work through the system of the animal, concentrate in the cornea, and kill the bacteria, allowing the eye to heal. Tetracyclines are available over-the-counter for this use, and are often quite effective. Other, prescription, antibiotics can be employed if necessary. Often, antibiotic injections alone are enough to successfully treat pinkeye. Systemic anti-inflammatory medications to relieve pain should be considered also.
The fact that most pinkeye cases are found out on pasture, far from working facilities, creates obvious challenges to the use of systemic antibiotics. By far the best option is to restrain the animal in an appropriate chute in order to administer treatment. This allows other procedures, like those listed below, to be completed as well.
Some cattle producers have employed tools such as dart guns and crossbows to administer antibiotics from a distance in a pasture situation. This veterinarian is admittedly conflicted about the use of these implements. On one hand, it’s hard to ensure that the injection is BQA- or carcass-friendly, as well as that the animal gets the proper dose, when darts are used. On the other hand, if that’s the only way an animal is going to get a necessary treatment, their proper use is preferable to letting the animal suffer.
2. Local treatment
This involves a subconjuctival injection of penicillin or a similar antibiotic in the affected eye. What we’re talking about here is not a simple “injection under the eyelid”. A small dose of antibiotic is injected under the outside layer of the bulbar conjunctiva (“white” of the eyeball). This appears to be an effective adjunct to systemic therapy, but it’s somewhat unclear exactly how it works. Some people feel that the small amount of antibiotic that leaks out into the tears kills bacteria on the surface of the eye. Regardless, this is a treatment that should be reserved for a veterinarian to perform—with good patient restraint in a chute.
3. Topical treatment
Through the years, producers have squirted purple liquids and puffed yellow powders into eyes in an attempt to cure pinkeye. We’ve since found that most of these old topical treatments—as well as most “home remedies” out there--don’t work and probably irritate the eye as much as help. A particular challenge is that the short duration of action of topical treatments means that in order to be effective, they need to be applied frequently.
Some approved products, however, appear to be helpful in promoting healing. These are specifically formulated for use in the eye and are available through veterinarians. When getting ready to apply something to the painful eye of a calf, ask yourself whether that is something you would put into your own eye.
4. Protective measures
Procedures aimed at protecting the damaged eye from irritants such as flies and strong sunlight make sense. These include gluing patches over the eye as well as surgical procedures such as third eyelid flaps or eyelid suturing. Those procedures should be performed with proper local anesthesia by a veterinarian. Simply isolating affected animals and providing them shade is effective, too.
Prompt antibiotic treatment—possibly including some of the other procedures listed above--of animals affected with pinkeye is still key to preventing long-term damage to the eye, and providing relief to the animal. Discuss with your veterinarian the best way to go about this in your herd this season.