Pinkeye : Can You Afford It?

A complete management approach aids in reducing infections.

Flies are a pain, sometimes literally. Large numbers of biting flies can result in reduced weight gain and added stress on cattle. But flies can also be a disease vector, spreading bacteria from one animal to another. Such is the case with pinkeye, a disease that costs the industry more than $150 million annually.

With younger animals more susceptible to pinkeye, it is often seen as a cow-calf problem. Older animals tend to develop immunity to the bacteria that cause pinkeye. Virginia Cooperative Extension reported calves diagnosed with pinkeye weighed 19.6 pounds less at weaning than healthy calves, while another study showed the loss to pinkeye 36 to 40 pounds at weaning. Also, it is estimated that a calf that is blind will gain 60 pounds less by weaning time. Pinkeye is the most common condition affecting breeding age beef heifers, and the second most common disease of nursing calves greater than three weeks old, eclipsed by scours as the most common.

The Bugs

Pinkeye is a general term for Infectious Bovine Keratoconjunctivitis, or IBK. For decades, the majority of pinkeye was caused by Moraxella bovis. Other infectious organisms include Moraxella branhamella ovis (Moraxella bovoculi) and more recently Mycoplasma bovis.

According to a published veterinary article by John Angelos, DVM, PhD, University of California, Davis, bacteria colonization can occur in the absence of clinical disease and can be cultured from the eyes of healthy cattle.

Plant awns, face flies, ultraviolet radiation from bright sunlight, dry and dusty environmental conditions and shipping stress are all risk factors associated with IBK in cattle. Additional risk factors that should be considered when making herd management decisions include trace mineral deficiencies such as selenium and copper deficiency. Flies can also serve as vectors.

Good management techniques can reduce the opportunity for a pinkeye outbreak. Those measures include a vaccination program, sound fly control and reducing the opportunity for corneal abrasion or injury.

Peggy Thompson, DVM, Professional Services Veterinarian for Boehringer   Ingelheim said the ideal time to vaccinate calves is prior to the fly season so that calves have time to develop immunity from the vaccine. Producers should consider a pinkeye vaccine when they are turning cattle out on grass at two to three months of age.

Thompson said as far as vaccinating cows, she recommends an as-needed basis. Although cattle of all ages can be affected by IBK, most cases occur in cattle between two and 12 months. But if a producer is experiencing an outbreak, vaccinating cows can help slow the spread of the infection and reduce the duration of the disease.

Although it is not as common in older cattle, the disease can be found in stockers and even cows and bulls, especially if there are other factors that irritate the eye.

“Pinkeye is an infectious disease, but I look at it differently than some other vets,” said Robin Falkner, DVM, Technical Services Veterinarian, Zoetis. “I try not to manage it as much as an infectious disease, but a secondary disease to corneal insults like the eye getting scratched, UV radiation, blistering, etc. When that happens, pathogens invade the damaged corneal tissue. Generally, in the absence of a corneal irritant, pinkeye is a minor infection for older animals.”

If you can limit the opportunity for corneal abrasions, you can reduce the opportunity for pinkeye, Falkner said. Look for situations that can damage the eye, such as cattle grazing deep into the sides of round bales, tall weeds, or excessive heat or flies causing cattle to bunch and swat each other with their tails.

Even though it’s not as prevalent in older cattle, it can be very costly.

In feeder cattle, managing pinkeye is about managing your marketing window, he explained. “That’s when it can decimate you the worst, at the time of marketing. Both calves and yearlings graze summer grass and are often marketed in the fall when pinkeye instances are high. I need to control the risk to my marketing.”

If we take a calf to the sale with pinkeye, it’s going to get a big discount, he said. But it can hit an operator on a bigger scale.

“What if I’m on a marketing contract to sell 500 yearlings, and I have a pinkeye outbreak just  before I ship the cattle? So instead of sending five loads, I’ve only got 3½ loads of marketable cattle. The buyer can walk away from that contract if I can’t fill it.”

Vaccine options

Federally licensed vaccines are available from multiple pharmaceutical companies and protect against the most common bacteria known to cause pinkeye, Moraxella bovis. Label claims vary by product and range from “aid in reduction in disease” to “aid in the prevention and control.”

Thompson explained it’s important for a producer to read the label on the vaccine. Some pinkeye products on the market require a second shot. Without the booster, the vaccine is not as effective.

“We have a single dose pinkeye vaccine that is combined with blackleg called Alpha 7 MB1,” she said, “which eliminates the need for an additional shot at branding and does not require a booster.”

In addition to both brand name and generic products for producers to choose from, multiple modes of administration are also available.

An implant-style, single dose vaccine that is administered at the base of the ear or subcutaneously in the neck is a newer technology known as Solidbac Pinkeye IR/PR from Zoetis. The implant contains two small pellets, an Immediate Release (IR) pellet, offering initial protection, and a Programmed Release (PR) pellet, which serves as a second dose within one  administration.

Some veterinarians recommend an autogenous vaccine made specifically for the bacteria in a given herd. According to Jessica Newberry, DVM, Technical Services Veterinarian,
with Phibro, 52% of eye swabs sent to their lab from producers experiencing IBK in 2015 and 2016 had more than one bacteria present.

“We study a lot of samples and run further diagnostics, and direct producers to work with their veterinarians to choose the strains to give the best protection in the form of an autogenous vaccine,” Newberry said.

An autogenous vaccine can be developed in four to six weeks after isolates have been collected.

“It’s a tailor made solution for each producer. We also work with vets to bring several producers together under the nonadjacent use regulations set forth by the USDA. If you can establish an epidemiological link between farms then you can get permission to use on multiple farms for broad coverage,” Newberry explained. “If you have a certain bacteria on your place and share a fence line, you can bet your neighbor will have that bacteria as well.”

According to the USDA, licensed autogenous vaccines are only prepared for use by or under the direction of a veterinarian or client with a valid VCPR (veterinary client patient relationship.) Autogenous products are not subject to the same licensing requirements and proof of efficacy as federally licensed vaccines.

Regardless of the type of vaccine chosen, a complete approach will improve the success of limiting a pinkeye outbreak in a herd.

“Just a fly tag won’t do it. Just the pinkeye vaccine doesn’t do it,” Falkner said. “It’s a multi-bacterial disease, and we have to put systems together to mitigate the risk of those diseases occurring. That means utilizing a sound fly control program, weed management, shade management and vaccinations.”

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