Next time beef producers look their animals in the eye they might want to check for a common bacterial disease, says a Purdue University beef specialist.
Pinkeye causes inflammation, swelling and, if left untreated, the rupturing of the infected eye, says Ron Lemenager. The discomfort produces stress for the animal, which, in turn, affects its productivity.
The summer and early fall months are prime times for pinkeye transmission.
"Pinkeye is a disease that is very contagious," Lemenager says. "It is caused primarily by a bacteria called Moraxella bovis (M. bovis). A more recently identified strain called M. ovis can also cause pinkeye. While humans can get pinkeye, the disease is separate and distinctly different from the pinkeye cattle get."
In cattle, M. bovis and M. ovis often are spread by face flies. The flies move from cow to cow feeding on eye secretions, passing the bacteria to uninfected animals.
Once infection takes place the disease begins to manifest itself within a few days, Lemenager says.
"Early detection becomes important in this process," he says. "The first clinical sign that you're probably going to see is a runny eye. When the eye starts to water significantly, that becomes a trigger for a producer to be looking for pinkeye.
"In the very early stages of pinkeye the membranes of the eye become red and swollen. As pinkeye progresses, the animal starts to squint and may walk around with a closed eye, because sunlight becomes a significant irritant to the infected eye."
Within two weeks of contracting pinkeye, an animal's condition worsens.
"As we move further into the classical cases of pinkeye, the cornea will become cloudy and, eventually, you'll see a white spot or a spot that's bluish in color. The eye will create an ulcer," Lemenager says. "The ulcer is almost like a large pimple on the eye. If left untreated, the ulcer will rupture and the fluid in the eye will be expelled - at least to some degree. At that point the animal will probably lose sight in that eye."
Traditional pinkeye treatments include intra-muscular or subcutaneous (Sub-Q) injections of oxytetracycline and covering the eye with a patch.
"You can also use an antibiotic injection under the eyelid," Lemenager says. "The concept here is that when you inject under the eyelid, the antibiotic will be released slowly over the eye and take care of the M. bovis organism."
In severe pinkeye cases, a veterinarian might be called in to suture the eye closed until the eye heals.
Producers can reduce the risk of M. bovis transmission by sanitizing their hands and farm equipment, controlling flies and weeds, and reducing dust, seedheads and pollen.
"I'm a big believer in the prevention of pinkeye," Lemenager says. "Since one of the contributing factors to pinkeye is face flies, if we can control face flies we can go a long way toward controlling pinkeye."
Control methods for face flies include insecticide treatments applied directly to cattle. Methods include insecticide-impregnated ear tags, dust bags that sprinkle insecticide over cattle as they walk under the bags, pour-ons applied to the animal's top line and sprays. Flies can develop resistance to insecticides, so producers should consult a local veterinarian or a Purdue Extension entomologist or county educator before applying a product.
"Another area to consider is weed control and seed head control," Lemenager says. "That probably means going out and clipping pastures. You don't have to clip them down to grazing height. You might set your mower to a depth of about a foot and just knock off the seed heads and take the pollen away. Also, if you've got hay bunks, keep that hay low so that as the cattle eat they are not dropping dust and seed heads and thistle seed into their eyes."
Lemenager also recommends vaccinating cattle and controlling other pinkeye-related diseases, such as chlamidia, mycoplasma, acholeplasma, infectious bovine rhinotracheitis and bovine viral diarrhea. "There's also a pinkeye vaccine," he says. "If a producer has had problems with pinkeye in working cattle that might justify vaccinating the animals."
For more information on beef cattle diseases and management issues, visit the Beef @ Purdue Web site, located at www.ansc.purdue.edu/beef/ .