UACES Facebook Pinkeye incidence in Northwest Arkansas cattle expected to be high this season
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Pinkeye incidence in Northwest Arkansas cattle expected to be high this season

By Ryan McGeeney
U of A System Division of Agriculture
June 24, 2016

Fast Facts:

  • Pinkeye is a bacterial infection often transmitted by face flies
  • A moderate winter increases chances of high face fly activity this summer
  • Over-the-counter vaccines for Pinkeye available 

(564 words) 

LITTLE ROCK — Cooperative Extension Service agents in counties throughout Northwest Arkansas have reported an increase in incidences of bovine keratoconjunctivitis during the last month, University of Arkansas System Division of Agriculture experts said this week. The bacterial infection of the sensitive tissues of the eyes of cattle and horses is more commonly known as “Pinkeye.” 

The infection is often spread among cattle and horses by face flies, an insect that typically emerges in the spring after winter dormancy. Kelly Loftin, extension entomologist for the Division of Agriculture, said face fly activity in Arkansas typically exceeds the established treatment threshold in two out of every five years, and 2016 will mark the second year in a row for very high activity in the state. 

“A lot of years, you’ll see face flies congregate in protected areas like attics or church steeples,” Loftin said. “If you get some warm dates in the winter, they’ll become somewhat active. After they’re active, if you get a cool snap, you’ll get some mortality. This year, we had a fairly mild winter, with no major cold snaps. I think that’s part of the reason we’re seeing them again this year.” 

Loftin said the treatment threshold for face flies on cattle is the presence of 10 flies on an animal’s face at one time. 

Because the face fly (musca autumnalis) has a sponge-like mouth, it tends to traffic viruses and bacteria as it feeds on the protein-rich mucus membranes of the affected animals. Heidi Ward, veterinarian and assistant professor of animal science for the the Division of Agriculture, said that true Pinkeye is caused by an opportunistic bacteria. 

“Pinkeye can’t just get onto the eye and cause an infection,” Ward said. “There has to be an initial irritation to the eye, which is why we pay attention to environmental conditions. If the cattle are in areas with tall grass, dry air or dust, they are predisposed to infection.” 

Left untreated, Pinkeye and similar infections can lead to blindness in livestock. Additionally, the infections can be so painful and irritating that animals may stop eating. 

“It’s beyond unpleasant and irritating,” Ward said. “To give you some perspective, the cornea has the most sensory nerves of any tissue in an animal’s body, so it’s extremely painful.” 

Veterinarians recommend an anti-inflammatory injection, which provides pain relief and helps with the inflammation, she said. 

“Any time cattle are in pain, they’re going to stop eating — and from a beef cattle perspective, that’s a bad thing,” Ward said. “That’s why I tell the producers that they should be preparing for this, because the affected cows are going to go off feed, they’re going to lose weight, and you’re going to lose value in that particular animal.” 

Loftin said growers can help lower infection rates in cattle with topical insecticide treatments on the backs and faces of cattle. Ward said an effective vaccine is widely available over the counter to prevent Pinkeye and similar infections, although growers should take care to purchase their vaccines from reputable sellers and follow the label directions. 

“A vaccine protocol will always be better than antibiotics, for several reasons,” Ward said. “It’s still considered a natural treatment to seek protective immunity, rather than treating with a chemical, and there’s no worry about residue problems.” 

To learn more about disease and pest management, contact your local Cooperative Extension Service agent or visit


The University of Arkansas System Division of Agriculture offers all its Extension and Research programs and services without regard to race, color, sex, gender identity, sexual orientation, national origin, religion, age, disability, marital or veteran status, genetic information, or any other legally protected status, and is an Affirmative Action/Equal Opportunity Employer.  

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Media Contact: Mary Hightower
Dir. of Communication Services
U of A Division of Agriculture
Cooperative Extension Service
(501) 671-2126

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