A New Look at Pinkeye
Pinkeye continues to frustrate cattle producers despite advances in knowledge and vaccine technology, notes University of Missouri (MU) Extension Veterinarian Craig Payne. "Dealing with pinkeye is frustrating at best." While there's no magic bullet that will guard herds from pinkeye, understanding the complex causes of pinkeye can help producers make smarter decisions about managing outbreaks in their herds.
Payne shared recent findings about pinkeye at an Oct. 8 field day at MU's Hugo Wurdack Farm in the Ozarks.
Pinkeye in cattle is an infectious and highly contagious disease that results in inflammation of the membrane lining the eyelid and eyeball. Without prompt treatment, afflicted livestock lose weight or gain less weight and may suffer eye damage, leading to extra costs for producers and steep discounts at the sale barn.
Under ideal conditions, healthy cattle can fend off infection from pinkeye-causing bacteria. Pinkeye results when some trauma or irritant allows an infection to take hold. It could be airborne dust and pollen, tall grass, the increased ultraviolet light of summer, or infestations of face flies, which are both an irritant and a vehicle for spreading infection within the herd.
"It was traditionally thought that the same set of factors contributed to pinkeye outbreaks in a herd," Payne said. However, some suggest that cases of pinkeye within a herd may be triggered by different things. For example, factors such as UV exposure and face flies may contribute to pinkeye in part of the herd while for other cattle it might be a different set of factors, such as UV exposure, stress and eye injury from tall grass.
Another complication is that the organism traditionally associated with pinkeye — Moraxella bovis — may not be the only organism involved. In the last few years, a similar microbe called Moraxella bovoculi has been recovered from the eyes of cattle showing signs of pinkeye. This may be one reason why pinkeye vaccines have had mixed success in preventing outbreaks.
These complications mean that producers might still have a number of cattle with pinkeye despite aggressive efforts at prevention and control. But that doesn't mean that the effort was wasted.
"If you had done nothing, the situation might have been much worse," Payne says. "The more things you can do, the more likely you are to reduce problems in your herd."
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