I’m hearing about more cases of pinkeye in cows and in their calves than in the last few years. A few milder winters might have had something to do with it — not enough overwintering face flies (that spread the disease) were killed off.
Each cow or calf infected with untreated painful pinkeye (caused by the Moraxella bovis bacteria) has a good chance of going blind. It practically makes any semi-blind animal worth hundreds of dollars less than its herdmates; whether it’s a cow that cannot find a mineral feeder and becomes so mineral/ vitamin deficient that she fails to rebred or it’s a hungry calf that doesn’t come up to the creep feeder. As a result, it has a lower saleable weaning weight in the fall.
Here are three important steps to minimize risk of disease spread:
- Know symptoms of pinkeye in cattle and the life cycle of the face fly, its transmitter.
- Put the cattle on a well-balanced mineral (and vitamin) feeding program.
- Make strategic use of insecticides on cattle grazing pasture.
Walk through the cow herd regularly, and look for signs of pinkeye. The initial source of eye irritation may come from abrasive pasture grass or dusty ground in pasture areas, but by far the main reason for cattle eyes to water excessively is the common face fly.
Like many other cattle fly pests, face flies go through a four-stage metamorphosis that encompasses about 21-25 days.
Understanding pinkeye and the face fly in the first protocol has little to do directly with the second protocol (mineral supplement) of pinkeye control, but there is a definite link. A good trace-mineral program should be provided in order to promote healthy eye tissue and surrounding areas as well as strengthen immunity against this disease. Producers in problematic pinkeye areas should feed a commercial beef “breeder” mineral at the rate of three to four ounces per head per day, year round. The fortified cattle mineral should contain at least four specific micronutrients that help combat pinkeye — Vitamin A and zinc as well as selenium and vitamin E .
Assuring mineral and vitamin status is optimized within the animal is a good idea to help control/recovery of pinkeye in cattle and should underscore the above third and final protocol — strategic use of pesticides. For instance, some producers apply one organophosphate- or pyrethroid-impregnated ear tag per head to one ear. They do this before letting cattle out on pasture.
I also understand that some producers forgo putting ear tags into their cattle because they feel that the efficacy of four-month ear tag control may not coincide with a major buildup of flies toward the end of the summer.
I have a friend that runs a 150 cow-calf operation on the eastern Prairies who doesn’t use ear tags in his cattle for this sole reason. As an alternative for face fly control, he applies a pour-on pyrethroid insecticide (one per cent cyfluthrin) to every animal just prior to releasing his cow herd onto pasture. About six weeks later, he and his brother walk the herd with backpack sprayers filled with malathion and they lightly spray the body of each animal.
I asked him, “How do you treat about 300 animals (calves included) on open pasture?” He laughed and said it’s amazing how fast all animals come around when you shake a bucket half-filled with corn! He realized a long time ago that you don’t fool around with pinkeye in cattle — employ a natural (he feeds a breeder mineral on pasture) and an insecticidal means to avoid the serious economic losses when even one animal loses sight from one eye.