By Emily Wilmes
University of Minnesota Extension
All cattle producers know what a nuisance flies can be to their animals in the summer. These flies bring with them all sorts of potential problems, including pinkeye. Pinkeye is a painful disease caused by the bacteria moraxella bovis, and can cause reductions in weaning weights of as much as 17-65 pounds per animal. What can we do about this pesky problem? Let’s take a look at both prevention and treatment of pinkeye in cattle.
In most situations, the first step in gaining control of pinkeye is to control the flies. There are several options for fly control, including fly tags, pour-ons, sprays, dust bags and back rubbers. Face flies play an important role in the spread of pinkeye, as the irritated eye produces excessive tearing that attracts them. Face flies then pick up the bacteria that causes pinkeye and transfer it to other animals. Unlike horn flies, face flies spend very little time on the animal. So, one face fly can spread pinkeye to several animals in the same day. That’s why it’s very important to get aggressive about pinkeye control as soon as you see any sign of it.
A key component of pinkeye control is pasture management. Grass that is headed out can irritate eyes, causing them to tear and thus attracting face flies. Keeping pastures trimmed can reduce this irritation.
When treating pinkeye, the key is to catch the disease early. Generally, a long-acting oxytetracycline antibiotic is very effective against moraxella bovis, but resistance isn’t uncommon. If this occurs, your veterinarian may need to conduct a culture and sensitivity test to determine which antibiotic the bacteria is sensitive to.
Another key component to treating pinkeye is protecting the eye from sunlight, which is just as important as the antibiotic. Because ultraviolet rays can activate enzymes that cause more damage to the eye when the eye is infected, eyepatches are very effective in protecting the eyes from sunlight. The challenge can be keeping the eyepatch on the animal.
The best way to deal with pinkeye is to get ahead of it and stay ahead of it. Do this by using a broad-based approach that includes fly control, vaccination and pasture management. Consult with your veterinarian to develop a program tailored to your operation.