Also known as infectious bovine keratoconjunctivitis (IBK), pinkeye can be one of the most detrimental and costliest diseases in the cattle industry. Monitoring the herd for the earliest signs of pinkeye is important to limiting the impact of the disease. While pinkeye generally occurs in animals less than 1 year old, animals of any age can be affected.
The first sign seen in calves developing pinkeye is excessive tearing. The animal may blink frequently and hold the eye either fully or partially closed due to sensitivity to light. As the disease progresses, a corneal ulcer is found in the middle of the eye.
Corneal ulcers are white in appearance and may even look gray in the center. Severe cases can result in blindness or rupture of the eye. After healing, a white scar on the eye often remains. Because one or both eyes can be affected, it is important to observe both eyes when performing daily “eye checks.”
Pinkeye is a very painful disease, and animals showing clinical signs should be treated as soon as possible. Calves with pinkeye are less likely to nurse or graze, resulting in weight loss. This setback in growth has lasting effects. Studies have demonstrated weaning and yearling weights are lower in animals that had pinkeye.
Weaning weights have been shown to be up to 40 pounds lighter in animals with pinkeye and up to 47 pounds lighter if they had pinkeye in both eyes as compared to non-affected animals.
The same study showed a 68-pound reduction in yearling weight and a decrease in average daily gain of 0.176 pounds per day in calves that had pinkeye pre-weaning versus non-affected animals. In addition, body composition traits in animals with pinkeye have shown to be negatively impacted.
In a study that evaluated the body composition traits in yearling cattle via ultrasound, calves with a history of pinkeye at weaning had a decreased rib fat depth and decreased ribeye area compared to non-pinkeye-affected animals.
Although we currently do not have information on performance in calves with a history of pinkeye beyond yearlings, the assumption lower growth rates will continue likely contributes to the discounted sale price received for calves with evidence of having pinkeye.
Pinkeye prevention
Prevention is key to avoiding this painful, economically devastating disease. Pinkeye is primarily caused by a bacteria known as Moraxella bovis, with other possible causes including Moraxella bovoculi, mycoplasmas and infectious bovine rhinotracheitis (IBR) virus.
Unfortunately, Moraxella bovis is found everywhere and therefore cannot be eliminated from the environment. It is spread through direct contact, nasal discharge, discharge from an affected eye and through mechanical vectors such as flies, feeding equipment or contaminated head gates.
Because pinkeye is easily spread, it is important to separate affected animals from the main herd and thoroughly disinfect any items used when treating animals, including your hands and clothing.
The most common way Moraxella bovis is spread is through face flies that can carry the bacteria on their legs for up to three days. Therefore, good fly control is vital to preventing pinkeye. This may include insecticide-impregnated eartags and dust bags. Other prevention measures include clipping pastures, providing sufficient mineral supplementation and timely vaccination.
Tall pastures can result in irritation or scratching of the eye, as can excessive dust, leading to Moraxella bovis gaining entry into the eye. Trace mineral deficiencies have also been associated with pinkeye, so it is important to work with your nutritionist and veterinarian to ensure you have an adequate mineral program.
Choosing a vaccine
Both commercial and autogenous vaccines are available to assist in controlling pinkeye. Commercial vaccines contain a set group of bacteria or viruses listed on the label and can be used on any farm for pinkeye prevention. On the other hand, an autogenous vaccine – available through veterinarians – is one made from the bacteria and viruses taken from livestock on a selected farm.
Autogenous vaccines are a customized prevention tool that can be easily adapted to ensure the organisms causing the disease are included in the vaccine. Because bacteria and viruses that play a role in pinkeye are constantly changing, autogenous vaccines are an excellent way to prevent disease.
When pursuing an autogenous vaccine, a veterinarian will swab the eyes of animals with pinkeye prior to treatment and send samples to a lab for culture and evaluation. An autogenous vaccine company can then produce the customized vaccine for the veterinarian for use in the herd where swabs were taken.
In order to use autogenous vaccines on other farms, the veterinarian must request special permission from the state veterinarian, known as non-adjacent approval. This request can be made if there is a justification of disease risk due to exposure to the same bacteria and viruses from the original farm, such as proximity of farms and pastures, local movements of animals, common sale barns or disease patterns in the area.
For autogenous vaccine, animals at risk for pinkeye should receive two doses of the vaccine three to four weeks apart, according to label indications, with the last dose given six to eight weeks prior to pinkeye season.
As veterinarians, farmers and ranchers, we have a responsibility to prevent and relieve animal suffering. Having a good pinkeye prevention and “eye check” program in place will help avoid lasting economic losses but also prevent pain and disease, which is the right thing to do. 
PHOTO: An example of a scar resulting from pinkeye. Photo provided by Jessica R. Newberry.
* Potency and efficacy of autogenous biologics have not been established.
-
Jessica R. Newberry
- Technical Service Veterinarian
- Phibro Animal Health
- Email Jessica R. Newberry
