Let’s step away from politics and consumer trends for a moment and head back out to the real world of production agriculture.
In the summer months, as cattle graze on pastures, there are many considerations to think about — creep feeding, managing noxious weeds, fixing fence, breeding windows, watching for signs of pneumonia in calves, setting a weaning date, haying and the list goes on and on.
In the hustle and bustle of the long and busy days of summer, one thing that can sneak up on a rancher is pinkeye in cows and calves. Although pinkeye is a common infection that isn’t unfamiliar to ranchers, a refresher course is never a bad idea.
Here are four things to consider when evaluating, treating and preventing pinkeye in your cow herd this summer.
1. What is pinkeye and how does it spread?
Russ Daly, South Dakota State University veterinarian, explains that pinkeye is an infectious eye disease that is found in nearly all breeds of cattle throughout the world.
“Summer and early fall are the peak seasons for pinkeye, although it has been reported in all seasons. This is the time when implicated bacteria can be recovered from cattle eyes at the highest rates. It also is the time when environmental factors that influence the development of pinkeye are at their peak.
“Calves are much more susceptible to pinkeye than older cows or bulls, and animals that have been infected once are not likely to develop the disease again for more than a year,” he says.
“Environmental factors such as UV light, wind, dust, tall pasture grasses and weeds will lead to a higher rate of disease within a herd.
“Face flies are a very important factor in the spread of the disease within a herd. Flies pick up and spread the organism on their legs while feeding on the area around the eyes. The interaction of risk factors such as higher daily environmental temperatures and fly pressure tend to make cattle congregate into tighter spaces, allowing for easier transmission of offending organisms,” he says.
“The presence of other organisms in the conjunctiva, the pink inside lining of the eyelid and covering on the eyeball, may increase the severity of the disease.”
2. What are the clinical signs of pinkeye?
“Excessive weeping of the affected eye and closure due to pain are the two signs most commonly observed,” writes Brent Plugge, University of Nebraska-Lincoln Extension educator and Brian Vander Ley, DVM, at the Great Plains Veterinary Education Center.
“As the disease progresses, the cornea becomes cloudy or white. An ulcer frequently develops near the center of the cornea. Cattle with pinkeye keep the affected eye or eyes closed because of pain and to avoid bright sunlight. The course of the infection may run for several weeks.”
3. How do I treat pinkeye?
In a collaborative paper written for Virginia Cooperative Extension, leader author W. Dee Whittier, DVM, says, “Early treatment of cattle with pinkeye is important, not only for a successful outcome of the individual animal affected, but also to stop the shedding of the bacteria to decrease the risk of transmission to other cattle.”
He offers four treatment options, depending on how severe the pinkeye case is.
“In Stage 1, long-acting tetracyclines (Biomycin 200®, LA200®, or their generic equivalents) are effective at this stage of infection. A second injection given 48 to 72 hours later may increase the percentage of cattle that respond to treatment,” he writes.
“Another option is to inject penicillin and dexamethasone into the bulbar conjunctiva. The bulbar conjunctiva is the thin membrane that covers the white portion (or sclera) of the eye.”
Whittier adds, “Sprays and ointments are only effective if used three to four times daily, which generally is not feasible for most producers. Also, many of the commercially available ointments are either illegal to use in cattle or have very long withdrawal times.
“Give all SQ injections in the neck or in front of the shoulder. If treating several animals, you may want to wash your hands or change gloves between animals so you do not further spread this bacteria. Never use any powder or spray containing nitrofuracin, as its use in cattle has been illegal since May 2002. A veterinarian should be consulted before using any other medications.”
4. How can I prevent pinkeye?
Daly says, “Because bovine pinkeye can’t easily be replicated by simple exposure to the bacteria, it could very well be considered an environmental disease. Reducing the pinkeye risk for pasture cattle means addressing their environment.
“The role of the bacteria should not be entirely discounted, however. Pinkeye tends to affect multiple cattle in a herd. When the bacteria is successful at infecting an animal, there’s more of it around to spread to another by flies or direct contact. Exposure to higher bacterial numbers means less of an irritation is needed for an infection to start,” he adds.
“It’s easier said than done but controlling the environmental aspects of pinkeye through fly control shade and clipping tall grass should be considered. While the success of pinkeye vaccines is erratic, they should also be discussed with your veterinarian. Just because the environmental aspects of pinkeye may be hard to control, producers should still do what they can to protect cattle from this painful, production-robbing disease.”
Now that we’ve heard from the experts, I would love to hear some boots-on-the ground advice. What are your best tips and tricks for preventing and treating pinkeye?
The opinions of Amanda Radke are not necessarily those of beefmagazine.com or Farm Progress.