As if cattle producers aren’t stressed enough with the drought, we are now dealing with high numbers of pinkeye in our calves.
We get calls daily from our producers asking how to treat and what they can do to try to prevent it.
Pinkeye is really called “infectious bovine keratoconjunctivitis” or IBK. Infectious meaning transmissible from one animal to another. Bovine meaning cattle species. Kerato is the cornea, conjunctiva is the tissues surrounding the eye, and itis means inflammation.
All of this comes together to mean inflammation of the outer part of the eye as well as the eye tissues that is spreadable between cattle.
The tricky part about this disease is that the bacteria that cause pinkeye are cultured from the eyes of normal calves. This means that they are opportunistic bacteria in which they live on the eye waiting for a breech in the protective barriers of the cornea and surrounding tissues, allowing them to proliferate.
The most common culprit is Moraxella bovis which is a bacterium that is always evolving creating new strains that might even be specific to your herd. M. bovis have pili that allow them to attach to the cornea and remain there. They also produce hemolysins that damage white blood cells which then leads to more enzymes being released that lead to corneal ulceration and even liquefaction.
Mycoplasma bovoculi is the other most common bacterium that causes pinkeye in our area. When M. bovoculi is found with M. bovis, the disease is typically more severe as the bacteria help each other proliferate.
Cattle will often have tearing (lacrimation), squinting (blepharospasm), inflamed and enlarged tissues surrounding the eye (conjunctivitis), white spots (corneal opacity), indents in the cornea (ulcers), blindness, and even eye rupture.
Diseases that are hard to control are typically multifactorial. Pinkeye is a perfect example. Not only are the bacteria already living on the eye waiting for their opportunity to proliferate, but the environment, the diet, and the flies play huge roles in this disease.
This year, pinkeye is rearing its ugly head early due to the heat, wind, sunny days with lots of UV light, and dust. Did I mention the dust?
Hauling and comingling cattle also makes pinkeye worse due to stress and close proximity to the other animals, allowing flies to easily move between animals.
Flies not only irritate the eye, but they feed on the eye secretions. They then take the bacteria in the secretions and pass them between cattle.
The grass in our area is tall and has headed out. The awns are sharp and create an eye irritation. Pastures with weeds are even worse for having plant-life with eye irritants.
When there’s a lot of different ways to treat a disease, that means that there is no one way that works the best. I think pinkeye is a good example of this. Most veterinarians in our area will choose injectable oxytetracycline (LA300 for example) as the systemic antibiotic but others can be used as well.
The next most common thing depending on the severity of the disease would be to glue a patch over the eye. This reduces irritants so that the eye is more comfortable. Some veterinarians sew the eyelids shut with a degradable suture material instead of using the patches but essentially working toward the same goal of reducing irritation. If this was a dog that had an ulcer on the eye, we would recommend antibiotic eye drops up to every two hours. But since that is obviously not feasible, we have to treat differently which in turn may be less effective. Either way, the goal is to minimize scarring of the eye, maintain vision, and increase animal comfort.
Eye pain is excruciating so if you have a calf up to treat pinkeye, it is a good idea to give a bolus of meloxicam or inject/pour with flunixin meglumine (Banamine for example) to aid in inflammation and pain reduction even though these pain relievers are short-lived (less than 24 hours of relief, usually).
Vaccinating your calves may or may not help control pinkeye, depending on what strains are in your herd. Commercial products are available and if they work in your herd, great! If they don’t, then your veterinarian can culture the eye and have a vaccine made specifically for your herd.
One thing that I typically caution my producers with is that if you are giving all of your spring shots at once, be careful when adding pinkeye. Too many gram-negative vaccines (pinkeye, seven-way clostridial, etc) cause endotoxin stacking which sets calves back or can even kill them. If it has worked for you in the past to give all your shots at once, great! If it hasn’t been good to your calves, then you need to split them up with two or more weeks in between.
We are currently recommending our producers to try to move calves off pastures with very tall grass with awns or cut the pastures. If you are not already fly tagging, pouring/spraying/fogging, or providing rubs for your cattle, then you really need to be.
Other ideas (whether feasible for your operation or not) for helping prevent and control pinkeye would be to provide shade for the cattle to help with the UV light exposure, make sure to clean areas with a lot of manure build up, and remove stagnant water sources.
Dr. Lainie Kringen-Scholtz is associate veterinarian at Twin Lakes Animal Clinic in Madison, South Dakota.
This vet report is provided in conjunction with Twin Lakes Animal Clinic and Howard Animal Clinic. Questions? Send an email to Lainie Scholtz, DVM at email@example.com, call 605-256-0123, or write 45305 SD Highway 34 Madison, SD 57042.