This month’s article will focus on pinkeye in cattle. The idea for this article came to me while visiting my local D&B store and overhearing two customers talking about how to best treat this disease. They misinformed each other for about 10 minutes, but did manage to purchase a few things that might be helpful.
Pinkeye disease is also known as Infectious Bovine Keratoconjunctivits (IBK) and is caused by a bacterium named Moraxella bovis. Infections are most common in the summer and the fall, and the infections can be widespread throughout the herd. Infected animals can experience decreased weight gain and milk production as well as blindness. Young animals are most susceptible due to some acquired immunity of older animals.
Damage to the natural defense mechanism of the eye predisposes it to infection. Dust, flies, grass awns, and UV radiation (especially in breeds lacking pigmentation around the eyes) all can damage these defense mechanisms. Once the infection starts, face flies can spread the infection quickly to other animals.
Symptoms of pinkeye include redness of the eye, excessive tearing, swelling and squinting. A small white area will be visible in the center of the cornea that will grow larger as the infection persists. Eventually, the cornea can become weakened to the point of rupturing.
Early treatment is the key to minimizing the damaging effects and spread of this disease. Fly control, dust control and other management of eye irritants must be done quickly to help prevent the spread. The disease can also be spread by failure to disinfect hands and equipment while handling the animals during treatment. The recommended treatment includes the use of a systemic antibiotic and treatment of the eye itself. Prescription antibiotics such as florfenicol (Nuflor) works well, but long acting tetracycline (LA 200) can also be effective. Calves can be fed oxytetracycline at a rate of 2 grams per head per day for 10 days. Injecting the affected eye subconjuctivally (underneath the thin membrane that covers the white portion of the eye) with 2cc of Penicillin daily for three days is also recommended. Injecting penicillin into the eyelid will not be helpful. I do not recommend putting powders or anything else that can be irritating into the eyes. I know grandpa swears by that powder but it further irritates the eye and is not as effective as the above treatments. Do not “cauterize” the eye with iodine.
Preventing disease consists of trying to control the predisposing factors such as flies, dust and other eye irritants. This can be done with insecticide ear tags and other topical insecticides. There are vaccines available for the prevention of pinkeye. These must be given before a disease outbreak occurs. Vaccinating in the face of an outbreak will be ineffective. The commercially available vaccines can work well. In cases where commercial vaccines fail to prevent the disease, a veterinarian can help develop a vaccine specifically for your herd problem (called an autogenous vaccine) that may be more effective.
I hope this article helps you understand this disease a little better. I know that similar discussions to the one I overheard are taking place in all of your stores. As always, advise customers to follow the label dosages and withdrawal times.