By: Leah Lee, DVM
Carson County Veterinary Clinic
Many producers deal with Infectious Bovine Keratoconjunctivitis or pinkeye. It is highly infectious and generally a herd problem. Young cattle, particularly Herefords and crosses are predisposed. The bacterial organisms isolated in cases of pinkeye have been identified as Moraxella bovis, Moraxella ovis, and possibly Mycoplasma bovoculi. This is a treatable disease, but it causes production loss by decreasing average daily gain and milk production.
Pinkeye is more common in the summer months. The increased dust, pasture stubble, and flies cause trauma to the eye and create a place for the bacteria to grow. Pinkeye lesions first appear in the center of the eye. In the beginning of the disease process, you may notice squinting, increased tear production, and reddening of the eye. As the lesion progresses, the eye will turn a blue or gray color and an ulcer will develop. If left untreated, the ulcer may deepen until the eye ruptures or causes blindness. Mild cases may heal, leaving a scar.
In very early cases of pinkeye, your veterinarian can inject medication in the tissue around the eye. Tetracycline, a long acting antibiotic, is also used because it is secreted in the tears. Repeated treatments may be necessary. Be sure to visit with your veterinarian, especially if the problem persists or continues to spread to other cattle. Eye patches are helpful to reduce spreading of the bacteria by flies and close contact. The patch shades the eye from the sun and provides a cleaner environment to heal.
Prevention practices need to be established. First, separate any affected animals from the rest of the herd. Fly control is also important. There are several options on the market. Insecticide ear tags will help control face flies. Use ear tags only during the fly season and then remove them to prevent resistance. An insect growth regulator feed additive is also helpful to decrease the fly population, and it is available mixed in mineral drums. The additive is eaten and then passed into the manure. The medication prevents the fly larvae from developing into adult flies. Controlling weeds and brush in the pastures will also help decrease trauma to the eye.
Pinkeye vaccinations are available. The use of these products has been questionable, because studies have shown that the vaccines do not significantly decrease the incidence of the disease. Since there is more than one potential cause, the bacteria in the vaccine may not be the one causing infection in your herd. Additionally, the cost of the vaccine may not offset your production loss. You will need to discuss the pros and cons of using these vaccines with your veterinarian to decide if they are right for your herd production practices.
The bovine eye has a wonderful ability to heal. Fly control, early detection of disease and treatment are the keys to dealing with pinkeye. Your veterinarian can help you make a plan for disease prevention and control in your herd.