Late spring and warmer temperatures means cattle producers need to be aware of problems related to pinkeye in their herds. Industry-wide, pinkeye leads to more than $150 million in treatment costs and decreased performance each year.
Grant Dewell, Iowa State University Extension beef veterinarian, said pinkeye is the general term for symptoms affecting the eye including excessive tearing, conjunctivitis or inflammation of the eyelid, photophobia or aversion to light and corneal ulcers. Bacteria like Moraxella bovoculi can also cause pinkeye but usually needs to be treated differently.
Pinkeye is primarily a summertime disease, but can be seen in all seasons of the year. It is more common in pastured cattle than in feedlot cattle, according to Dewell. The cost can be significant. Virginia Tech and South Dakota State researchers, among others, have reported a difference of at least 20 pounds in weaning weights for calves affected by pinkeye during the summer grazing months. This along with treatment, costs the U.S. cattle industry millions of dollars every year.
Pinkeye can be found in all ages of cattle, but more often in younger animals. It is spread by direct or indirect contact with infected animals. Flies are a major vector for animal-to-animal transfer. Other eye irritants include sunlight, dust, pollen and weed and grass seeds.
“Infectious bovine keratoconjunctivitis is the major form of pinkeye and is caused by the bacteria Moraxella bovis. Other pathogens such as Moraxella bovoculi, Moraxella ovis and Mycoplasma species can cause similar symptoms,” Dewell said.
Viruses such as Infectious bovine rhinotracheitis can cause eye lesions, but not with a viral infection.
Symptoms
The first sign of pinkeye is an excessively watery eye. There may also be a slight reddening of the inner or outer surface of the eyelid, and frequent blinking. The infection can cause the cornea to become inflamed and turn cloudy or blue in color. If an ulcer develops, it is generally in the middle of the cornea. The animal will likely hold the eye partially or completely closed as the disease progresses.
“Depending upon the severity, a white scar could remain in the affected eye,” Dewell said.
The disease usually takes four to eight weeks to run its course, and damage to the eye can cause blindness.
“Affected animals will often decrease feed intake, usually blamed on pain or blindness,” Dewell added.
Prevention
Fly control is critical in controlling pinkeye since flies are responsible for moving bacteria around and causing irritation to the eye surface. Fly tags and pour-on are popular ways to control flies.
Vaccines are another preventative measure for pinkeye prevention. Central Iowa Hereford breeder Becky Simpson said in past years she has had a problem with pinkeye in the herd, but after swabbing affected eyes, her local veterinarian included the strain in an autonomous vaccine for the area.
“We are pleased with the results of using the vaccine specific for our area and we also fly tag all our cattle to help in prevention,” Simpson said.
Commercial vaccines are also available, but may not be as effective if other types of bacteria are present.
Dewell said a good mineral program can also inhibit eye problems. Those with insect growth regulators can help with fly problems. Oilers and misters are other ways to help control flies.
“Limit other eye irritants such as dust or grass pollen and seed heads by keeping grass trimmed. Tall grass that is seeding can cause enough eye irritation to let any bacteria present colonize the surface of the eye,” Dewell said. These are also all practices Simpson uses on her farm.
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Treatment
If the animal already has pinkeye, prompt treatment is the best way to help further infection or spread to other animals. Prompt treatment will also help prevent permanent damage to the eye. Dewell said consulting a veterinarian is advised.
“Due to the excessive pain of a pinkeye lesion, non-steroidal anti-inflammatory drugs may provide some relief. This would require a prescription from your veterinarian,” he said. “Protecting the eye from the sunlight will decrease irritation to the eye and minimize pain and weight loss.”
Eye patches are available and can be glued over the eye to provide protection. In some cases a veterinarian may suture the eye closed for complete protection.
“The main thing is to catch problems early before several animals have problems,” Dewell said.
Jennifer Carrico can be reached at 515-833-2120 or [email protected].
