Many people may be familiar with the term pinkeye, which is a symptomatic term for redness of the eye caused by conjunctivitis.

However, they may not be aware that cattle can also get pinkeye, called bovine keratoconjunctivitis. It is caused by a different bacteria than human pinkeye, and is generally a more severe problem in cattle.

Pinkeye in cattle is most often caused by the bacteria, Moraxella bovis. The bacteria is spread by flies. Flies cause irritation in cattle eyes by feeding on eye secretion, allowing the bacteria an opening for infection. Bacteria use tiny hairs to attach to the white part of the eye. Flies then carry the bacteria from animal to animal.

Once introduced to the eye, bacteria causes more tearing and attracts flies. An early symptom of pinkeye is animal squinting. As the infection develops, the cornea becomes cloudy and may eventually turn white (the cornea is normally transparent). If not treated, the animal may become blind and the eye may protrude from the socket.

Beef producers take pinkeye seriously, for the health and well-being of the animal and their business. Calves stressed with pinkeye eat less and require more time to reach market weight.

Pinkeye is generally treated with a shot of antibiotics and steroids to the eye. Antibiotics will kill bacteria and steroids will diminish inflammation. Cattle generally begin to respond to the shot within 24 hours.

However, beef producers use preventive management practices to create an environment that limits cattle susceptibility to pinkeye infection.

These management practices include improving herd immune status, controlling face flies, minimizing exposure to bacteria, and reducing eye irritants.

Producers generally follow four steps in implementing these management practices:

• Maximize herd health and immune status. A good health program would include proper nutrition, adequate vitamin and trace mineral intake, solid vaccination program, parasite control, and basic biosecurity practices.

• Control face flies. Face flies can play an important role in the spread of pinkeye. Their abrasive blotting mouthparts irritate the animal’s eyes, stimulating tears and mucus that feed the insects.

Bacteria in the secretions of infected cattle can survive on or in face flies for two to three days and infect other animals when the flies feed again. Face flies may move as far as four miles during their life so they can easily transfer pinkeye from herd to herd and farm to farm.

• Maintain an irritant-free environment. Irritations to the eye allow bacteria to invade and cause pinkeye. Chance of eye irritation may be reduced with good face fly control; grass height control, especially tall grass with seed heads; and reduced stress by providing shade, clean water and adequate animal space.

Provide shade to protect from the harmful UV rays of the sun. Cool, clean drinking water (instead of stagnant pond water) is critical because intake is greater with clean water and this helps provide plenty of fluid to the corneal surface, especially important in dry, dusty, and/or windy conditions.

Tears are essential eye defense mechanisms, as tears wash away pathogens and tear proteins are an important component of protection. Regularly check and clean automatic waterers.

• Minimize exposure to bacteria. Early detection of animals with the first clinical signs (tearing, squinting, and blinking) and then prompt, effective treatment are essential to reducing spread of pinkeye to herd mates and limiting damage to the eye.

Pinkeye may be a problem for cattle producers. Producers use management practices to reduce infection but may have to use antibiotics and steroids to cure infected animals.

Additional information on cattle pinkeye may be found at

Lentz is extension educator for agriculture and natural resources for the Ohio State University Extension Service in Hancock County. He can be reached at 419-422-3851 or via email at

Lentz can be heard with Vaun Wickerham on weekdays at 6:35 a.m. on WFIN, at 5:43 a.m. on WKXA-FM, and at 5:28 a.m. at 106.3 The Fox.