One of the questions I am often asked is: “How common is pinkeye?” The short answer is: It depends.
Some farms never have pinkeye, which is also known as infectious bovine keratoconjunctivitis (IBK). Other farms struggle with it year after year. All too frequently, a farm is pinkeye-free for years and suddenly has an outbreak, which is detrimental to employee morale as well as animal comfort. Let’s take a quick look at the common causes and transmission, signs, treatment and prevention strategies for pinkeye.
Causes and transmission
• Bacterial infection of the eye
o Moraxella bovis, Moraxella bovoculi and Mycoplasma bovoculi are the most common bacteria found lately in Wisconsin.
• Viral infection
o Infection bovine rhinotracheitis (IBR) can cause pinkeye but is less common.
• Physical irritants
o Long grass, weeds, excessively stemmy hay, dusty bedding or blowing sand scratch the eye, allowing bacteria to invade.
• Flies
o Face flies in particular are attracted to tearing and circulate bacteria between animals.
• Direct contact with infected animals
o Pinkeye used to be most common in spring and summer due to flies, but several bacterial strains spread directly from animal to animal. Thus, pinkeye lasts through the winter on some farms.
Clinical signs
• Excessive tearing
• Frequent blinking or squinting
• Red conjunctiva (the lining around the eyeball)
• Blue or white spot on the eye
• Rupture of the eye
• Blindness
Treatment
• Antibiotics
o Multiple effective drugs are labeled for pinkeye treatment, but antibiotic resistance does occur. Consult your veterinarian for specific antibiotic recommendations.
• Topical sprays
o These can be helpful in very early pinkeye cases
• Eye patch or third eyelid flap
o Protect the eye from UV light, flies and irritants.
Prevention
• Excellent fly control program
o Use larvicides or insect growth regulators to prevent development of adult flies.
o Use fly tags, pour-on insecticides, fly sprays or oilers to minimize flies on cattle.
o Use fly baits, traps or fly predators to deal with existing adult flies.
o Remove manure and bedding regularly.
• Minimize environmental irritants
o Keep pastures and weeds trimmed.
o Don’t blow in bedding.
o Decrease dust as much as possible by spraying driveways, feed alleys, etc.
Vaccination
• Follow a good IBR vaccination schedule developed by your veterinarian.
• Consider using a pinkeye vaccine. For a pinkeye vaccine to be effective, it must contain the strain affecting your cattle. Commercial pinkeye vaccines are not cross-protective, so if your cattle have a different strain than what is in the vaccine, the vaccine will not help.
• Most commercial vaccines protect against various strains of Moraxella bovis. A couple of vaccines protect against Moraxella bovoculi. Currently, there are no commercial vaccines for Mycoplasma bovoculi.
• Custom-made pinkeye vaccines are increasingly popular as the pinkeye bacterial strains continue to change.
o To make a custom vaccine, a veterinarian swabs the eyes of cattle with the earliest signs of pinkeye (tearing, excessive blinking) before they are treated with an antibiotic.
o Swabs go to a custom vaccine manufacturer who grows and identifies the bacteria, then creates a vaccine specific to the farm.
o Several veterinary clinics have created a custom-made vaccine that is a compilation of bacterial pinkeye strains isolated from their clients’ farms. These often provide excellent protection since they are specific to the practice area. Consult your veterinarian to see if they offer one.
Pinkeye is a multifactorial disease that requires several management strategies to overcome. Talk to your veterinarian today to see what you can do to curtail pinkeye on your farm.
