Pinkeye, or infectious bovine keratoconjunctivitis, is on the list of common wounds and diseases that is a highly contagious bacterial infection. It causes red, watery eyes, eye irritation, and, in the most serious cases, blindness.
Understanding the stages of pinkeye in cattle, can help you spot if something is wrong. When it comes to pinkeye, quick treatment is key to keeping the condition under control for the infected animal.
What Causes Pinkeye in Cattle?
Pinkeye is most often caused by Moraxella Bovis (M bovis), a bacterial organism. Although this is the most common bacteria that can cause pinkeyes in cattle, there are also some other potential causes. These include infectious bovine rhinotracheitis virus (IBR), mycoplasma bovis, and Moraxella bovoculi. All of these bacteria increase the risk of infection in the affected eye.
One of the reasons why M. bovis is one of the most common causes of pinkeye in cattle is because the bacteria itself has little hair-like structure, called pili, which helps it attach to the conjunctiva of the cornea. The bacteria then colonize, which causes the first signs of inflammation that we associate pinkeyes with. The condition will spread from the cornea to the lid and chamber of the eye.
In addition to these bacteria, foreign objects in the eye can also increase the risk of pinkeye in cattle. Even tiny things like seed heads, dust, and pollen can get into a cow’s eye, scratch the cornea, and make it easier for M. bovis to attach to the cornea. These irritants also cause the eye to water, which further spreads the bacteria.
How Pinkeye is Transmitted in Cattle
As its name suggests, the bacteria that causes pinkeye resides in the eyes and nasal cavities of infected cattle. Cattle may be asymptomatic, meaning that they don’t show any symptoms for up to a year, making pinkeye extremely transmittable to other healthy cattle. Transmission can occur through direct contact between an animal infected with pinkeye. Because the bacteria live in secretions of the affected cattle, this transmission can happen through direct contact, such as if the liquid from an animal’s watery eyes or cow udders gets on another animal or transmitted through indirect contact. Indirect contact may look like an animal coming into contact with an infected inanimate object, such as a face covering or feeder.
One of the main transmitters of pinkeye is face flies. Face flies travel from animal to animal frequently, and even more, they feed on the tears from cattle’s eyes. Because of this, they can quickly spread pinkeye from animal to animal, even between animals miles apart, causing a potential pinkeye outbreak.
Stages of Pinkeye in Cattle
There are four main stages of pinkeye in cattle. Let’s look at these in more detail and explain what to look for if you suspect your cattle are infected.
Stage one is the first stage when cattle are infected with pinkeye. In this stage, you may notice excessive eye-watering and photophobia, or increased sensitivity to light. As a result of this photophobia, cattle may spend more time in the shade, which can decrease their grazing time and potentially cause weight loss.
The animal may blink more frequently to try to alleviate some of the pain and uncomfortable symptoms. During stage one, you may also notice that the animal’s eyes are red and inflamed. There may be a small ulcer in the center of the cornea. It can look like a white spot. You may also notice the beginning of an edema in the cornea, which can cause the eye to become cloudy.
One of the most important symptoms of stage two is that in addition to the symptoms listed in stage one, in stage two the ulcer will likely spread across the cornea. This causes increased cloudiness in the eye and can lead to compromised vision. You may also notice increased redness because the blood vessels in the eye are growing across the cornea to help with healing. In fact, the cornea will appear pink (hence the name).
Stage three of pinkeye in cattle is one of the most serious stages and can lead to irreparable damage. In this stage, the ulcer in the eye becomes larger and covers most of the cornea. In addition, the interior eye fills with a pus-like substance called fibrin. In this stage, the eye will actually appear more yellow than pink or the normal brown.
Stage four is the most extreme pink eye stage and in this stage, many vet professionals recommend removing the infected eye due to risk factors for the affected animal and the cattle herd. This is because the ulcer will likely extend completely through the cornea, resulting in the iris protruding through the ulcer. There is little to no way for the eye to heal from stage four of pinkeye because even after healing, the iris will form adhesions to the cornea.
In stages 1-3, the blood vessels will start to recede once the ulcer is healed. Because of this, the eye may remain cloudy for a short period of time. Eventually, the eye will become clear again. The animal may have a small scar that can slightly impair their vision.
How to Treat Pinkeye in Cattle
By understanding the stages of pinkeye in cattle, you can see how important it is to quickly and effectively treat this disease. Not only will this help limit the risk of the disease progressing, but it will reduce the risk of transmission to other cattle.
Over the counterPink Eye Spray can work very well, but more extreme cases will likely require a visit from the veterinarian. They may recommend medications such as ceftiofur, tulathromycin, and florfenicol. They may also recommend intramuscular antibiotic therapy, especially for stages one and two.
While undergoing treatment, help clean and protect the cornea and the corneal ulcer and lesions from UV light, flies and other insects, and other possible irritants by using a topical Pink Eye Spray. Eye patches can also help minimize the risk of infection. These topical eye solutions are designed to speed up the recovery process and are safe, non-toxic, non-irritating, and don’t use any alcohol or antibiotics.
In more severe cases, like in stage three, a veterinarian may recommend a subconjunctival local injection. This can be used alone or in combination with topical antibiotics or ointments.
If you are using a topical treatment to treat pinkeye, consistency is key. Usually, these products need to be used multiple times a day. Because of this, many people choose to do these injections because they are quicker.
How to Prevent Pinkeye in Cattle
Of course, the best thing to do is to prevent your cattle from getting pinkeye altogether. But as we saw in the information about transmission, this might be difficult. Still, there are some things you can do to help reduce the risk of your cattle contracting pinkeye.
The first is to have a solid fly control program since face flies are responsible for a lot of the transmission of pinkeye. There are many ways to reduce the number of flies around your cattle, including:
- Feed your cattle a larvicide or insect growth regulator 30 days before flies emerge
- Use fly tags that contain an insecticide
- Use a pour-on that helps prevent flies and parasites
- Use a dust bag or cattle rub
- Spray your cattle with pink eye spray throughout the year if they are contained enough
Although you can never eliminate face flies, controlling their negative impact is key to controlling the spread of pinkeye in cattle.
In addition to fly control, you should always keep your cattle up-to-date on vaccines, including those for infectious bovine rhinotracheitis (IBR) and bovine viral diarrhea virus. These vaccines may also help limit the spread of M. bovis, the bacteria that causes pink eye. Although there are some commercial vaccines designed to treat pinkeye, there are so many strains of M. bovis that these vaccines aren’t consistently effective.
Another thing you can do to help prevent pinkeye and other conditions is to ensure that your cattle have a good nutritional and mineral program. Always provide your cattle with enough grazing, clipped pastures, a safe space without frayed or sharp edges, and enough shade.
Pinkeye can be dangerous to cattle, spread quickly, and impact a large population relatively quickly. Because of this, it’s important to limit your herd contracting pinkeye by providing them a healthy diet and plenty of room to graze, keeping them up to date on vaccines, limiting face flies that can carry the disease, and monitoring your cattle regularly. The four stages of pinkeye in cattle are important to understand so you know what to look out for and so you can help treat the condition quickly before it gets worse.
Reviewed by Dan Richardson, Veterinarian
Dan Richardson has been a practicing veterinarian for over 10 years. He specializes in surgery and orthopedics. Dan is originally from rural western Nevada and attended the University of Idaho for undergraduate study and Oregon State University for Veterinary School. The Richardson Family enjoys camping and spending time on the water fishing, paddle boarding, or digging their feet in the sand somewhere warm.