Business : Pinkeye Season in cattle is coming

Now that the heat of summer has arrived, we’ll soon see increases in the face fly population and we already have plenty of grass seed heads to set the stage for increased pinkeye cases in cattle. Pinkeye, or infectious bovine keratoconjunctivitis, is an infectious and contagious disease that affects the eyes of cattle. It is characterized by reddening and inflammation of the lining or conjunctiva of the eyelid and eyeball. It is primarily a summertime disease but is seen during all seasons. Pinkeye affects all breeds of cattle, and is more common in pastured cattle than in feedlots.

Pinkeye is found in cattle of all ages but primarily young animals. The causative agent is the bacterium Moraxella bovis. Older cattle often carry the bacteria but are immune to actual infection and do not show symptoms of the disease. Since young animals have low immunity, they are most susceptible and are usually on pasture where they may not be observed every day. Pinkeye is spread by direct or indirect contact with infected cattle. Face flies are a major vector feeding on eye secretions from an infected animal and transfer the bacteria to another animal.

Irritation of the eye is a major predisposing factor to pinkeye. Sunlight, dust, pollen, weed and grass seeds or awns are major eye irritants. Irritation causes inflammation that allows the organism to invade the eye tissues and multiply.

The first sign of pinkeye is excessive tearing of one or both eyes. As the disease progresses, the animal holds the eye partially or tightly closed. If untreated, the cornea becomes inflamed and turns white. The cornea may ulcerate. As healing begins, blood vessels migrate toward the ulcer. A white scar may remain in the center of the affected eye. The disease course is usually 4 to 8 weeks.

Damage to the affected eye may result in permanent blindness. Affected calves often lose weight because they refuse to nurse, graze, or drink because of pain or blindness. In addition to treatment and labor, reduced weaning weight is a major cost of pinkeye.

Pinkeye treatment can be successfully treated, but it must begin early, when calves first show signs of disease, and it must be repeated until healing is complete. Consult your herd veterinarian for proper treatment recommendations.

Prevention is more rewarding and cost-effective than treatment. Good face fly control is important and should include a variety of strategies throughout the summer. Some strategies include insecticide ear tags, dust bags or “face mops” or sprays on a regular basis.

Eliminating eye irritation is also important. Seed heads of grasses and weeds, along with pollen, cause extensive eye irritation. Cattle graze close to the ground where mature plants may cause eye irritation. Mowing reduces eye irritation. Several pinkeye vaccines are available, but veterinarians report variable success with these products. In herds where pinkeye is a frequent problem, early vaccination may be recommended so that immunity is established prior to exposure. Remember to work with your veterinarian to develop control strategies specific for your herd.