Pinkeye is a general term used to describe symptoms including excessive tearing, conjunctivitis, photophobia and corneal ulcers. Pinkeye is primarily a summertime disease of pastured cattle but can be seen during all seasons of the year. Pinkeye is diagnosed in cattle of all ages, but occurs primarily in young animals. Calves afflicted with pinkeye can weigh 20 pounds less at weaning compared to normal calves.
Irritation of the eye is a major predisposing factor to pinkeye. Common eye irritants suspected to predispose some cattle to pinkeye include sunlight, dust and pollen. Weed and grass seeds or awns also are major eye irritants. Face flies transmit the bacteria to the eye and if the eye has been irritated, bacteria can colonize the surface of the eye.
The first clinical sign of pinkeye is excessive tearing of one or both eyes. If untreated, the infection may progress causing the cornea to become inflamed and turn a cloudy white to blue color. Typically, an ulcer will develop in the middle of the cornea. Damage to the affected eye may result in permanent blindness.
Pinkeye often can be successfully treated, but treatment should begin when calves first show signs of disease. Protecting affected eyes from sunlight and flies is helpful.
Evaluate your fly control program regularly during the fly season and adjust as necessary to maintain good control of fly populations. Good face fly control is an important part of pinkeye control and programs should be started early in the season to prevent fly populations from being established.
Insecticide ear tags, dust bags, sprays and larvicidal products are helpful to control flies. Mowing pastures can reduce eye irritation from pollen or seeds.
Although several pinkeye vaccines are available, efficacy is very limited. Vaccination of calves at grass turnout is less beneficial then vaccinating mid-summer when calves immune system is better able to respond. Work with your veterinarian to develop a plan to prevent and treat pinkeye that works for your operation.