Tri-State Neighbor: South Dakota Farm Newspaper

Summer is passing rapidly and surprisingly after all the early rains, most of us could use a good shower of rain.

Even with all our preparations some of our clients are experiencing a common summer problem, pinkeye (infectious bovine keratoconjuctivitis).

Pinkeye is a bacterial infection on the surface of the eye. The disease starts with tearing of the eyes and moisture streaming down the animal's face. The eye becomes painful and very sensitive to light, causing the calf to squint or stand with its eye closed. After about one day, a small ulcer begins to form on the cornea. The size and severity of this ulcer determines the outcome of the disease.

Initially the ulcer may appear as a small white spot on the eye. Intervention and treatment at this time usually results in very minor damage. As the ulcer grows, the eye will become more painful and increases in size. The cornea becomes white and then blue from excess fluid held within the cornea.

As the ulcer deepens, the eyeball may actually rupture. The iris of the internal eye may plug the perforated ulcer keeping the eye's shape, but resulting in heavy scarring.

If the eye continues to leak, its size decreases and persistent blindness will result. In other cases, the internal damage to the eye results in a secondary glaucoma or enlarged eyeball. This also results in the loss of sight in the eye.

The organism responsible for pinkeye is Moraxcella. For years we thought M.bovis was the only pathogen responsible for the problem. We have seen many cases of pinkeye in feedlot cattle during the winter, what we call “winter pinkeye.”

Cultures of the animals have resulted in the growth of Moraxcella ovis, thought to be a pathogen of sheep. If producers have a mixed infection in their herd, it may explain why commercial vaccines are ineffective because they only contain M. bovis.

There are many things which predispose cattle to pinkeye:

€ Cattle on low energy or insufficient diets;

€ Vitamin and mineral shortages or imbalances;

€ Concurrent diseases - IBR, BVD, etc.;

€ Excessive ultraviolet light (lack of shade);

€ Dust or pollen irritation;

€ Face flies.

Pinkeye can be best prevented by appropriate vaccination with a vaccine containing the pathogens found in the herd. Usually producers have an initial case or two (indicator cases). If they do not remove predisposing factors and initiate treatment, producers will probably have a total herd outbreak in about two weeks.

Treatment generally includes:

€ Booster of the pinkeye vaccine;

€ Injectable vitamin A;

€ Long acting oxytetracycline to infected animals;

€ Injection of antibiotics into the eyelid of the infected eyes and then patching or sewing these eyes to protect them and allow them to heal;

€ Control of flies through sprays or pour-ons;

€ Elimination of any predisposing factors.

Infectious pinkeye can result in significant losses in a herd. Not only will calves with blindness and enlarged eyes be sorted at sale time, but infected calves are usually 25-40 pounds lighter at weaning.

Through careful planning and a complete management program, producers will minimize their pinkeye losses. This will reward them with healthy calves worth premium dollars at market time.

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