A new strain of Moraxella is causing more incidence of pinkeye in cattle
Pinkeye in cattle can cause deep discounts at sale time by destroying the cornea of the animal’s eye. Pinkeye has historically been caused by the bacteria Moraxella bovis, but there’s a new strain circulating through herds today – Moraxella bovoculi – that’s causing producers to pull out all the stops to prevent the disease in their herds.
The clinical signs of pinkeye caused by either bacteria are the same. Producers can expect to see heavy tearing and photophobia, or extreme sensitivity to light. General eye irritation then progresses to corneal ulcers that eventually rupture.
Typically, the bacteria that causes pinkeye is transferred by flies – making fly control a key component to most pinkeye control programs, says Julie A. Gard, DVM, Ph.D., DACT, professor of large animal and food animal medicine at the Auburn University College of Veterinary Medicine.
“Any time you have a concentrated feeding operation, pay attention to waste removal,” she says. “That’s where the flies build up.”
Management can have a positive impact on pinkeye control as well. Gard recommends controlling all potential forms of eye irritation including flies, bedding, grasses or weeds that can be irritating to the eye area of cattle. Structural changes to the environment can even play a large factor, such as providing shade to reduce ultraviolent light irrigation.
“Early detection of eye problems of any kind is key,” Gard says. “Any time cattle are blinking and holding their eyelid closed or tearing up – that’s the time to treat.”
Commercial vaccines against Moraxella bovis may still help control pinkeye when battling traditional strains, adds Scott Hand, livestock manager with Vetericyn Inc.
“Vaccines will typically handle a couple of different strains, yet when a culture is taken of the disease that’s in the herd, it may be a totally different strain,” he says.
In areas where bovoculi is prevalent, producers can consider using an autogenous, or custom, vaccine that is made from bacteria found on the operation. In most cases, USDA regulations restrict the use of the vaccine to a specific herd or location. Autogenous vaccines can be cost effective for producers batting bovoculi, but it can be difficult to test the effectiveness of the vaccine without controlled trials.
Antibiotics are the most common treatment for cattle that are already infected. Gard recommends producers use an antibiotic that is labeled to treat pinkeye and use according to label directions.
“Some of the antibiotics aren’t used appropriately when producers treat pinkeye,” she says. “For example, one dose of oxytetracycline without a follow-up isn’t a full course.”
All antibiotic treatments have the potential to contribute to antibiotic resistance, warns Melinda Mayfield-Davis, DVM, technical services veterinarian with Vetericyn Inc. Choosing pinkeye treatment options without antibiotics is an option producers are considering.
An alternative therapy to antibiotic treatments is now available to aid in healing the animal’s cornea and reduce pinkeye infection. It’s an antibiotic free hypochlorous acid spray that can be used in advanced cases or when early signs of pinkeye appear.
“A spray can help avoid the pain associated with giving an injection,” Mayfield-Davis says. “Some people can treat with a spray as opposed to having animals in a head gate. It can also avoid the muscle damage often caused by oxytetracycline and avoids that cost.”
The non-antibiotic spray treatment allows producers to treat for multiple strains of pinkeye without any withdrawal times or injections necessary, Mayfield-Davis says. In addition, three sprays to each infected eye twice daily can be economical compared to antibiotic treatments. Spraying even helps flush pollutants and foreign materials from the eye, which can contribute to the disease.
An antibiotic free hypochlorous acid spray can help producers manage pinkeye without withdrawal times and the expense of antibiotics, Gard says. In addition, her research shows the spray can actually help aid in healing.
“The spraying physically removes the bacterial mechanically by spraying it and decreases the number of Moraxella,” she says.
This action is present no matter what the strain of bacteria that may be causing the disease. In addition, anecdotal evidence from her research shows flies may be less prone to bothering the treated cattle after spraying.
Even with different treatment options, pinkeye prevention is really key, Hand says.
“Prevention is key, especially if we’re working on calf ranches or calf hutches,” Hand says. “When you see the first signs of the weepy eye, prevent that from getting to be a full-blown case of pinkeye. Try to get on top of that and get that animal treated up front for any respiratory issues and anything else that might reduce the stress on those animals.”
- Pinkeye is also called infectious bovine keratoconjunctivitis (IBK)
- The disease is most often caused by the bacteria Moraxella bovis
- Estimated annual losses associated with only decreased weight gain from infected cattle exceeds $150 million1,2
1 Gould S, Dewell R, Tofflemire K, Whitley RD, Millman ST, Opriessnig, Rosenbusch, Trujillo, O’Conner AM. Randomized blinded challenge study to assess association between Moraxella bovoculi and Infectious Bovine Keratoconjunctivitis in dairy calves. Vet Micro 2013 May; 164(1-2): 108-15.
2 Pugh GW, McDonald TJ, Kopecky KE, Kvasnicka WG. Infectious bovine keratoconjunctivitis: comparison of infection, signs of disease and weight gain in vaccinated versus non-vaccinated purebred Hereford heifer calves. Can J of Vet Res.1986: 50(2): 136-42.