Bovine pinkeye is a common disease found typically in beef herds. It is highly contagious, causing inflammation of the cornea and the lining of the eyelids. I can also cause ulceration in the eye. Pinkeye typically starts to occur in the spring and peaks in the summer before decreasing in occurrence when temperatures cool down in the fall. It is best to head off the disease because left untreated it can cause blindness and significant reduction in performance and cattle value.
Before we can know how to treat pinkeye, we must first learn what causes it. The primary cause for pinkeye is a bacteria called Moraxella bovis, but there are other, less common, strains that can cause symptoms. Cattle kept in pastures with tall grass or breeds that lack pigment on the eyelids (Herefords, Charolais, and their crosses) are more susceptible to developing pinkeye. Fly exposure is also a factor as the flys travel from cow to cow and can spread the disease.
Calves are also more likely than adults to develop pinkeye due to their underdeveloped immune systems, they haven’t yet had the chance to produce the antibodies to fight the disease.
How to Recognize Pinkeye
There are three stages of pinkeye:
-Stage 1: Cattle will have excessive tearing and become sensitive to light. They may blink more frequently and have redness along their eyelids. Cattle may exhibit pain which may decrease their feed intake resulting in loss of body condition or slowed growth. In stage 1, you may be able to see a small ulceration in the center of the eye which appears as a small white spot.
-Stage 2: In stage 2, the corneal ulcer continues to spread across the eye. More inflammation in and around the eye may occur and the cornea will start to become cloudy. In this stage, the blood vessels of the eye start to grow across the cornea giving the eye a pink-ish appearance, hence the name pinkeye.
-Stage 3: The ulcer now covers most of the eye and the inflammation continues to spread. The eye will look yellow-ish as it fills with a pus-like substance.
Management & Treatment
There is a vaccine available to decrease the likelihood that your herd will contract pinkeye, however it only vaccinates against one strain of the bacteria. This vaccine should ideally be administered in mid-late February, no later than early March, to ensure ideal efficacy and should be boostered once a year. In comparison to treatment of active pinkeye, vaccination is quite affordable and can save you time and stress later on down the road.
As previously mentioned, fly control is essential second to vaccination to help control the occurrence and spread of pinkeye. Insecticide pour-ons, fly ear tags, and feed additives are helpful in reducing the number of flies bothering your herd. Fly management techniques should be rotated annually to reduce the chance of resistance.
Mowing your pastures to prevent overgrowth is also helpful in decreasing possible eye irritants that expose cattle to bacteria. Ensuring your herd has shaded areas by way of lean-tos or tree cover is also beneficial to reduce UV exposure.
Though with the best management and vaccinated herds, pinkeye can still occur due to its various strains. At the first sign of infection, separating the affected cow(s) should occur. If you do develop an outbreak despite your best efforts, antibiotics such as Draxxin or LA-200 may be necessary. In smaller, more manageable herds, Vetericyn Pink Eye Spray may also be used. It is sprayed directly into the eye 1-2 times a day for as long as symptoms persist. Eye patches are also recommended to reduce the UV exposure and chance of additional irritants bothering the affected eye. This will also reduce the spread of the bacteria to the remainder of the herd.