July 2023


Face flies can spread pinkeye and one of the earlist signs of disease is when cattle’s eyes become teary.


MANHATTAN, Kan. — Anyone who has ever had a scratch on their eye or had dust get under their eyelid can attest to how painful an eye condition can be. Like people, cattle can also experience irritants in their eyes and that can often lead to pinkeye, say the experts at Kansas State University’s Beef Cattle Institute on a recent Cattle Chat podcast.

“Pinkeye is an eye infection that often first starts with watery eyes and then progresses to a swollen eye and even a white spot in the eyeball,” said K-State veterinarian Bob Larson.

Along with those symptoms, K-State veterinarian Brad White says cattle will tend to squint in the infected eye.

“Left untreated, cattle can develop corneal ulcers that are painful and make cattle light sensitive,” White said. “If you see the ulcers, likely damage to the eye has already been done.”

The veterinarians say the earlier the treatment begins the better the outcome will be.

“As soon as you identify the problem, the cattle can be treated with antibiotics and sometimes we will put an eye patch on them or sew the eyelid shut to give them some comfort as they recover because this is a painful condition,” Larson said.

When treated early, most calves are likely to recover, said Larson, but once the disease has progressed and there has been scarring to the cornea, the recovery time is much longer and there may be some or total vision loss in the infected eye.

While pinkeye can develop any time of year, the veterinarians say it tends to be more common in the summer.

“One way that pinkeye is passed from one animal to another is by face flies, so fly control is important in trying to reduce the likelihood of the disease spread,” Larson said. He explained that face flies are the size of house flies and tend to feed on secretions on the face and can cause damage to the cornea of a calf’s eye.

“Because face flies spend relatively little time on cattle it makes fly control more challenging because of the amount of time they spend away from the cattle,” Larson said.

Along with flies, other irritants to the eyes can come from seedheads, weeds, and dust in pastures, White said.

“Mechanical irritations, such as grass seeds, allow bacteria to get into the eye more easily and cause problems,” he said.

Larson added that if producers are experiencing a pinkeye outbreak in the herd, they may want to consider moving the cattle to a different grazing pasture.

“Sometimes we will move pastures to try to get them out of the field with the irritating factors such as seedheads or weed seeds,” he said.

To hear the full discussion, listen to the Cattle Chat podcast online or through your preferred streaming platform.


By Lisa Moser, K-State Research and Extension news service