Field work is progressing at a rapid pace in our area. By this weekend, we will all be ready for another shot of rain. Some alfalfa has already been baled and rain will stimulate the second cutting.
It's turnout time and we have received many questions about pinkeye. It seems some of our clients have had pinkeye problems this winter. In the past, winter eye problems were attributed to hay or dust injuring the eye. Now there is a new cause for "winter pinkeye" - Moraxella bovoculi.
We were taught that pinkeye in cattle is caused by Moraxella bovis. Previously, eyes that were cultured routinely grew M. bovis. Corporate animal health said, "Let's make a vaccine to help prevent pinkeye," and many mixtures, usually with "black leg," were marketed. Most vaccines were helpful, but it couldn't guarantee no problems. Most herds still had a few cases, and many clients blamed the vaccine. Remember - the vaccine can't totally eliminate the problem, only minimize the problem.
Now Moraxella bovoculi is cultured from 75 percent of the eyes we treat. I believe the vaccine for M. bovis has decreased the population of the bacteria in the environment, allowing M. bovoculis's populations to increase. The new "winter pinkeye" is less responsive to treatment and can occur throughout the year. Usually the damage to the eye is more severe and noticeable at market, causing sort-offs and decreased prices.
Controlling the pinkeye syndrome is becoming more complex with additional organisms. Mycoplasm organisms have also been cultured from bovine eyes and some believe it may be part of the problem. We recommend control by:
• Limiting irritation
• Fly control
We recommend finding an appropriate vaccine which works in your herd. Many herds have developed autogenous products from organisms isolated from their own calves. These products are all killed bacterins and require two injections for good immunity. These injections can be administered at turnout, and another late in the summer if problems occur, or when pre-weaning injections are given.
We also recommend a booster of pinkeye vaccine at weaning to help protect the calves in the feedlot. A new means of administration (Solidose) allows producers to accomplish two vaccinations with one pass through the chute. The implant contains a fast-release pellet and one which dissolves several weeks later. I know one licensed product (Pfizer) which is administrated in this manner. They are easy to use and seem to work well with no BQA problems.
There are certain pastures that are always a problem. It may be weed pollen, or even brome pollen, which makes the eyes tear. This wet face then attracts flies. Avoid pastures with fall grass at pollination time. Search for weeds and other irritants and try to minimize their effects. Some producers clip the heads off pasture grasses at key pinkeye times.
Flies are the mechanical vector that can carry the Moraxella organism for miles during the summer. Anything done to minimize insect irritation to the animal minimizes losses and maximizes gains. Dust bags, sprays, pour-ons, oilers and foggers have been used to help control fly populations. Fly tags have been belittled because flies are still on the animals, but the tags help reduce populations and decrease stress on the cattle. Recent research illustrated increased weight gains in tagged cattle; more than enough to pay for the tags at this $1.50 per pound market.
Visit with your veterinarian to devise a program for your herd. Keeping pinkeye lesions minimal in the herd will help produce more pounds at market, but also fewer sort offs, adding profit to the cow-calf operation.
Dave Barz is a veterinarian at Northwest Veterinary Supply in Parkston, SD.