Pinkeye in Cattle

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Large animal veterinarians in Catawba County are saying this is the worse year for pinkeye in cattle they have ever seen. Vets agree our county has the “perfect storm” for pinkeye in cattle this year.

What is Pinkeye? Pinkeye is a disease which causes an inflammation of the transparent cornea, the sclera (white) of the eyeball, and the conjunctiva, or the inside lining membrane of the eyelids. The disease is contagious and is most prevalent in the summer, but it may occur in any season. Infected animals lose weight or have severely reduced rates of gain and/or a drop in milk production. It is a major economic health problem in the cattle industry.

What causes pinkeye and how is it spread? According to eye doctors, a very thin membrane covers the eye. Once the eye is scratched, bacteria can enter quickly. Cattle eyes have this same membrane protection and have the potential of receiving small scratches while grazing. Once the eye is vulnerable to bacteria, and once just one animal is infected with pinkeye, the disease can be passed from animal to animal. By simply rubbing against each other, animals pass these bacteria to others in the herd. Also, flies are thought to be a main carrier of this bacteria transfer. There are four main types of flies found on cattle. The group called face flies seem harmless since they do not bite the animal for blood and feed only on mucus. However, they carry the bacteria that produces pinkeye. With the late rains this year, flies are prevalent. The rains also came just as the fescue pastures were putting up stems and producing seed heads which increases the danger of eyes being scratched.

What do cattle producers look for to identify pinkeye? A good manager will always first look at the eyes and the rear end of their cattle since these are usually the first visible areas affected by any type of health problem. Pinkeye affects only the eyes. It causes pain, profuse watering or tearing from the infected eye, squinting of the eyelids, and a slight cloudiness of the cornea from the start of the infection. The discharge from the eye has a tendency to mat on the face. The disease progresses RAPIDLY producing a white or gray spot which may easily be seen on the cornea below the center of the eye. This spot may develop into a small pimple like swelling which can lead to a corneal ulcer and complete blindness if not treated in a timely manner.

When and how do cattlemen treat pinkeye? The most important aspect of pinkeye treatment is that it must be given early. Calling a veterinarian early is highly recommended. The approved products to treat pinkeye include the long-acting tetracycline products (LA-200, Biomycin-200, etc.) and tulathromycin (Draxxin). These products should be given according to directions. Slaughter withdrawal rules should be followed exactly. There are a number of other treatments which a veterinarian can do to help control pinkeye.

What can cattlemen do to avoid pinkeye in their herd?

  • Mow the upper levels of pastures to cut off all material that may poke the eyes of grazing cattle.
  • Spray or treat for flies, making sure the spray kills face flies.
  • Check eyes daily for tearing and matted hair just below the eye.

Treat infected cows individually. If 15% of the herd is affected it is economical to treat the whole herd with the above recommended antibiotics. If you are not experienced, it is wise to call your veterinarian for assistance. If you have any questions regarding agriculture and gardening, feel free to call the N.C. Cooperative Extension of Catawba County office at 828-465-8240. If you have questions about livestock, ask for the Livestock Agent, Glenn Detweiler.