With livestock producers wondering why this same pinkeye issue in cattle is even tougher to get rid of lately, several veterinarians have important advice about how it has developed this summer, and how vital it is to treat it as soon as possible.

Livestock producers particularly in Nebraska and Kansas, say cattle have had some challenging cases of pinkeye recently. The eyes sometimes gets irritated by tall grasses or they can get poked by a tree branch, it injures the eye and it starts watering then flies are attracted to the water in the eye.

Pinkeye (infectious keratoconjunctivitis) begins from trauma by branches, grass or other other plants, and is fruther exasperated by exposure to ultraviolet light and high humidity.

“Presence of the precipitating infectious agents together with risk factors such as flies, plants, plant awns, etc., ultraviolet light and other risk factors, some likely unknown, result in pinkeye disease,” said Dale Grotelueschen, DVM, Professor Emeritus (retired) and University of Nebraska Lincoln director of the Great Plains Veterinary Educational Center. “The disease begins with inflammation of tissues around and including the eye itself resulting in excessive tearing and pain, resulting in squinting and partial or complete closure of the eyelids. As the disease progresses the cornea becomes inflamed and infected resulting in clouding because of fluid accumulation. As this progresses, ulcerations on the surface of the cornea can occur. Temporary blindness can occur during the disease until healing occurs, Some ulcers become so deep that the eyeball itself is ruptured. Corneal scarring and rupture often lead to partial or complete vision loss in the affected eye. Corneal scarring is common in severe cases that have healed,” said Grotelueschen, adding, “But experienced veterinarians and producers know that early treatment is highly important when cases begin to occur in order to avoid severe complications.”

Fly control is a component of reducing risk for pinkeye.

“However, fly control is seldom complete, and is variable. Forages in general are sufficiently tall in much of our grazing lands­­ that also contribute to eye irritation,” Grotelueschen said.

The best recommendations for treatment?

“I recommend producers treat pinkeye using the antibiotic recommend by their veterinarians,” said Annette M. O’Connor, professor of epidemiology and chairperson for the Department of Large Animal Clinical Sciences at Michigan State University. “We have useful data that antibiotics result in faster cures, and that’s important because we also have evidence that pinkeye is painful,”

The activity of antibiotics is limited to their effects on bacteria that are present, Grotelueschen said.

“They (antibiotics) help give animals an edge in fighting diseases such as pinkeye. Cleanup, repair and healing of tissues are up to the respective systems of the animal that accomplish these. Eye tissues, such as the cornea, take a considerable amount of time to heal. These considerations are important when assessing treatment response and healing time,” Grotelueschen said.

PINKEYE PREVENTION

Regarding prevention, unfortunately it’s still not 100 percent effective.

“Going forward, I do not know of proven effective ways to prevent pinkeye,” O’Connor said. “There are very few well-conducted studies on pinkeye vaccines, and I’m not aware of any well-executed studies showing that available products are effective. This refers to autogenous or commercial vaccines. Pinkeye is a frustrating disease; there can be no doubt.”

“I concur with Dr. O’Connor, especially how frustrating PE (pinkeye) is for everyone,” Grotelueschen said.

“Subjectively, we have seen many more case submissions for PE than in a typical June. PE is consistently listed in the top two or three animal health challenges faced by producers in many surveys. It is definitely a significant and costly challenge in systems across the region,” said J. Dustin Loy, DVM and an associate professor at the UNL School of Veterinary Medicine and Biomedical Sciences. “The best possible thing is to treat as cases as early as possible. This reduces healing time, likely pain and discomfort, and would reduce bacterial numbers in infected cattle. Currently, the best options are to work with their veterinarian to control face fly burdens. These not only can potentially transmit bacteria between animals, but the mouthparts are irritating to the eyes when they feed on them.

Some cattle produers are wondring if there is a new strain this year.

“There isn’t a new strain. The predominate organism class has shifted some, but no new strain,” said Gregg Hanzlicek, DVM at Kansas State Veterinary Diagnostic Laboratory at Kansas State University’s College of Veterinary Medicine in Manhattan. “Pinkeye is multifactorial big time, therefore control/treatment is never absolute in most cases.”

“Discover the underlying issue. What is compromising the cornea, and discover the predominate organism involved by collecting several eye swabs for diagnostics,” Hanzlicek said.

“There are some published case studies of severe pinkeye outbreaks in cattle resolving very soon after removing various fly attractants from the farm, such as nearby manure piles or decomposing feed materials,” said Halden Clark, DVM at the UNL Great Plains Veterinary Educational Center in Clay Center, Neb., adding, “The most effective strategies are careful fly control and prompt treatment of cattle that contract it. Specific drugs for treatment fall under the Veterinary Client Patient Relationship. There are a number of bacteria and viruses that can cause it, and there are complex interactions between them.”

“It’s a very frustrating condition, and we all need to learn more to make improvements and manage this disease,” said Grotelueschen. “We need to better understand the factors causing the conditions, which may offer keys to improvement.” ❖

— Hadachek is a freelance writer who lives on a farm with her husband in north central Kansas and is also a meteorologist and storm chaser. She can be reached at rotatingstorm2004@yahoo.com.