Pinkeye is prevalent throughout the United States and is a major health problem with a significant economic impact on the cattle industry. Pinkeye, the common name for infectious bovine keratoconjunctivitis (IBK), was first recognized as a contagious disease more than 100 years ago.

IBK is an infectious disease condition that causes inflammation of the cornea, the white of the eyeball, and the conjunctiva, or the inner lining membrane, of the eyelids. The eventual result may be corneal erosion and scarring.

Pinkeye is most prevalent in the summer, but it can occur year-round. In most outbreaks, 10% to 30% of a herd may have infected eyes, and infected calves will have significantly reduced rates of gain. Cattle of all ages may become infected, but calves are particularly susceptible.

Cause of pinkeye

A bacterium, Moraxella bovis, is considered the primary infectious agent. However, in recent years, through the efforts of veterinary researchers and diagnostic labs, Moraxella bovoculi has been confirmed as a common singular or co-pathogen. Diagnostic submissions over the past few years have confirmed the importance of both M. bovis and M. bovoculi in pinkeye infections. A recent diagnostic lab report on more than 400 cases and 900 isolates found 44% of infections with both bacteria and 36% with M. bovoculi only.

Within a herd, bacteria are primarily spread by face flies. The bacteria carried by a face fly can remain viable for several days.

Signs of pinkeye

Pinkeye affects only the eyes. It causes inflammation, pain, extensive tearing from the infected eyes, eyelid squinting, and a slight cloudiness of the cornea at the onset. Without immediate treatment, the disease can progress rapidly, into a white scar. It may also develop into a small pimple-like swelling, which can lead to a corneal ulcer.

Pinkeye prevention

Your veterinarian can help develop a strategy for preventing pinkeye in the herd. Preventive e orts should be directed at a comprehensive and timely vaccination program, fly control, proper mineral and vitamin availability, and pasture management.

Available commercial vaccines can help prevent pinkeye. It is critical for an effective prevention program to utilize vaccines with multiple diverse Moraxella strains in both M. bovis and M. bovoculi vaccines. Complete pinkeye protection includes vaccination with both vaccines. The two vaccines for pinkeye should be administered several weeks before fly season. The pinkeye vaccine is most important in calves, as cow vaccination will not benefit the calves.

Pinkeye treatment

Despite preventive measures, some herds may have a few animals that develop pinkeye and require treatment. The best treatment includes a therapeutic antimicrobial and revaccination.

If treated in the early stages of infection, a single treatment may be sufficient. A second treatment, 3 to 4 days later, may be needed for severely affected animals.

There are several effective antibiotics specifically labeled for treating pinkeye. Moraxella spp. are generally susceptible to long-acting antimicrobials like oxytetracycline and tulathromycin. Severe cases of pinkeye or delayed treatment may result in severe corneal scarring and possibly blindness. Early detection and sound treatment are critical in an outbreak.

PREVENTION is the critical success factor in controlling pinkeye in cattle.