envato.com, by FabrikaPhoto
envato.com, by FabrikaPhoto

Detecting and treating pink eye

When pink eye strikes a herd, it can be a pain. Not just for the producer tasked with treating the outbreak, but especially for the infected animal. “It is an irritating and painful disease,” Barry Whitworth, DVM, specialist with the Oklahoma State University Cooperative Extension, said. 


The first signs associated with pink eye are discharge and tears running from the animal’s eye. Other indicators of infection include a water stain below the eye, squinting or keeping the eye closed. 

The next stage of pink eye is inflammation of the eye. “As the disease progresses it is obviously going to get that typical redness, bright red color because the sclera (white of the eye) and the conjunctiva (thin membrane that covers the white of the eyeball and the eyelid) are infected,” Whitworth explained.

The most obvious sign of the disease is the cloudy, hazy, bluish or grayish color of the cornea. Veterinarians say this is when most producers realize their livestock has pink eye. When the animal’s eye starts to show discoloration, the disease has significantly progressed. 

If producers catch pink eye in its beginning stages, then the easier it is to successfully treat it. 

“If you can treat early most of the time you are not going to have any trouble with it,” Whitworth added. 


Conjunctivitis commonly known as pink eye, is caused by bacteria called Moraxella Bovis. 

The bacteria are a common inhabitant of the eye. “We think something has to happen to that eye that lowers the immunity and that gives the Moraxella Bovis a chance to take a hold in that eye and start an infection,” Whitworth explained. 

If a different virus is already infecting animals within the herd, then producers may see pink eye spread rapidly through the herd. However, typically pink eye cases are isolated to a few animals. 

Flies are another culprit in the spread of pink eye. When flies feed near an animal’s eye, it can pick up the Moraxella Bovis bacteria and spread it to other animals. 


Dr. Whitworth recommends examining the eye before taking any other action. Many times, a grass seed, thorn or other foreign body gets lodged in the animal’s eye. The foreign body in the eye creates irritation which can lower immunity and trigger the infection. 

The exam should include prying open the upper eyelid, lower eyelid and the third eyelid to look for a foreign body. Producers may want to use a large cotton tip applicator to swab under the eyelids in order to remove anything that should not be there. 

Producers need to keep forceps or tweezers handy in case it is necessary to remove the foreign body. In some situations, veterinarians numb the eye with eye drops prior to an exam and treatment. Most cases of pink eye are treated with injectable antibiotics, tetracycline and Draxxin are mostly commonly used. A patch placed over the infected eye helps to protect it from dust and sun. 

In addition, producers will want to consider administering a nonsteroidal anti-inflammatory medicine to ease the animal’s pain. “I think we forget that this is a painful disease,” Whitworth added. “It is really important that we give those cows some relief with some type of nonsteroidal anti-inflammatory drugs. I think that is important.”

If pink eye is left untreated, there a chance it will eventually clear up on its own. However, severe cases result in permanent damage to the cornea, leaving it scarred and white. “I like to tell people it is like putting on a pair of glasses and painting a while spot on those glasses and see how well you can see after that,” Whitworth shared.

In the most extreme cases, the cornea ruptures and the internal components of the eye protrude through the ruptured cornea. This leads to blindness in the damaged eye. 

Veterinarians recommend isolating the animal or animals with pink eye from the rest of the herd until the infection is gone. This will reduce the spread of the disease. 


Dr. Whitworth advises producers to make sure their herds are current on their vaccinations. Proper nutrition also plays a role in prevention. In addition, Vitamin A serves as a critical supplement due to its importance in producing healthy epithelial tissue. 

Keeping flies to a minimum is another prevention measure. In areas where tall, fescue seed heads are present, cut those areas to minimize the chance of a fescue seed scraping or getting caught in an animal’s eye. Lastly, offer animals spaces with shade that are free of dust and debris.


Please enter your comment!
Please enter your name here