Pinkeye (Infectious Bovine Keratoconjunctivitis) can be a costly disease for cattle producers during the summer and early fall in Kansas. Understanding the cause, signs, treatment, and prevention of this disease can go a long way in reducing pain and discomfort for the cattle and the pocket book.
Cause: Pinkeye is a multifactorial disease that is often caused by bacteria, Moraxella bovis. Factors that can contribute to the disease are as follows:
- UV radiation from the sun
- Grass awns, scratches on the eye from grazing tall grass
- Face flies
- Flies feed on discharge from the eye. They can spread the bacteria rapidly from animal to animal.
- Concurrent diseases (IBR, BVD)
These factors can cause physical irritation to the surface of the eye initiating the disease, or inhibit the body’s natural defense mechanisms.
Signs: Excessive tearing, blinking, and squinting are all early signs of pinkeye. The excess tears often drain down the face collecting dirt and grime. This can be seen from a distance. As the disease progresses the eye becomes extremely red, the clear part of the eye becomes white and cloudy. The clear cornea can form an ulcer and even rupture in severe cases.
Treatment: Injectable long acting oxytetracycline products are often used with good effect. There are other veterinary prescription options as well. It is always important to work with your local veterinarian and have a valid Veterinary Client Patient Relationship (VCPR). If pinkeye is becoming an issue on a premise, the veterinarian has the tools and expertise to help in face of an outbreak. Samples may be sent to the diagnostic lab to determine the best course of treatment. To help with the healing process, it is recommended that a patch be glued over the eye. An eye patch does two things to promote healing. First, it takes away the irritant of the sun’s UV radiation. Eliminating this irritant will increase cattle comfort during the healing process. Second, the patch can help decrease the spread of the disease by physically blocking flies from feeding on the tears of the affected eye.
Prevention: Prevention starts with ensuring optimal herd health. Quality forage along with Vitamin and trace mineral supplementation supports a strong immune system. The immune system can be hindered during times of stress from shipping, weaning, weather, and changes in feed. This is why a solid vaccine program against respiratory pathogens such as IBR and BVD is important. These viruses can contribute to the severity of pinkeye outbreaks. There are pinkeye vaccines available on the market, but inherently they have some downfalls. There are many different subtypes of the Moraxella bovis bacteria. Many of which can be isolated from just one infected animal. Although the vaccines have several strains, unfortunately they are not cross protective. This means if a different strain of the bug infects the animal, disease will still occur. The pinkeye vaccine still has its place in a herd health plan, but disease may still occur. If these vaccines are to be used, it is important to administer at least 4 weeks prior to pinkeye season (some products require 2 doses) to ensure adequate response. Other ways to prevent the disease is to manage the environment and vectors of the disease. This can include mowing tall strands of grass and weeds in the pasture reducing the scratching potential while grazing. Fly control is also very important. Strategies may include fly tags, pour-on products, dust bags etc. Providing simple shade structures can decrease the irritation of the sun during the middle of the day. Also isolating infected animals may decrease the spread to other animals. Using these strategies will help prevent pinkeye severity on an operation.