Battling Pinkeye on the Dairy

Published on Fri, 05/07/2021 - 9:11am

Battling Pinkeye on the Dairy.

 By Jaclyn Krymowski.

 The signs are relatively tell-tale – sickly, off-colored eyes often accompanied by an obvious unsightly discharge. In the cattle world we call this pinkeye, but it is more specifically known as Infectious Bovine Keratoconjunctivitis.

In the dairy industry, pinkeye poses a special risk of rapid spread in confined spaces. As it can show up with little to no warning, and sparing neither cows nor heifers, an understanding and response to this issue is key for farm managers.

Besides the discomfort, the disease can cause lifelong eye damage or even permanent blindness in some cases. Not to mention, be quite costly in terms of loss and expensive when it comes to antibiotic treatment and lost milk – if you factor in vaccinations it goes up even more.

The highly contagious nature of pinkeye coupled with its somewhat random nature makes it difficult to totally prevent or eliminate it even with the best of protocols. But the early steps taken for treatment with some basic prevention can go a long way in severity and damage caused.

Specifically, pinkeye in cattle is most often caused by the bacterial pathogen Moraxella bovis. But this is not the only culprit – other Moraxella species and some viruses can also be to blame. In a particularly difficult outbreak that is unresponsive to treatment, culturing may be necessary to determine the exact cause.

One factor that remains the same always accelerating the disease is the presence of ultraviolet rays found in sunlight. Studies have found that when there is great exposure to ultraviolet light, there is a much greater chance of an animal contracting pinkeye after exposure to pathogens with higher severity.

This is part of the reason why animals lacking pigmentation around the eyeball are considered at significantly higher risk for pinkeye – because they don’t have this added layer of protection against the harmful rays.

Another major factor contributing to pinkeye outbreaks and their severity are flies. Face flies and horn flies are particularly harmful as they will pass the bacteria or viruses picked up from one animal’s eye to the next. This is not just within herds – flies can also go across neighboring farms and spread diseases like pinkeye that way as well.

While there is only so much that can be done in this regard, having an established integrated pest management program in place keeping flies to a reasonable number can go a long way in preventing the spread of pinkeye once established.

Damage to the cornea and surrounding tissue of the eyeball can also help promote and encourage pinkeye infections. When cows or heifers are grazing long and abrasive grasses or eating a particularly irritating TMR, they may be getting extremely small cuts and scratches to the delicate ocular surface.

This can cause tearing and discharge that not only attracts flies potentially carrying the pathogen, but it can also leave a damaged surface much easier for the Moraxella bacteria to cling to and proliferate on.

In the case of bacterial pathogens, antibiotics can be an effective route of treatment. When done at earlier stages, early treatment can be simple and non-invasive with a simple sub-Q or intramuscular injection using a standard antibiotic such as oxytetracycline or penicillin.

However, in more serious cases of infection and/or advanced stages, a direct ocular injection into the delicate membranes may be the best option. While this mode of treatment is very effective, it should only be attempted by individuals with specific training and skill in this application as mishandling or improper restraint could permanently damage the eye.

Post- treatment, care should be given to animals as they recover. For individuals who are housed outdoors or heavy exposure to sunlight, eye patches can be applied during the healing process. This blocks out the harmful ultraviolet rays and also protects the eye from other irritants and flies during this time.

Likewise, pasture and feed can be managed to promote healing. This could entail cutting down overgrown, tall and abrasive pastures and reducing dust in barns and feed. Offering additional shade in the summer months can also be a helpful way to cut back on damaging ultraviolet light exposure.

Because it is somewhat unpredictable in its appearance and severity, totally preventing pinkeye isn’t a simple task. It can strike any group of cattle at any time of year.

Commercial vaccinations are available, but there is ongoing debate and discussion as to their effectiveness. Incorporating an annual or seasonal vaccine should be discussed with your veterinarian if they are going to be worthwhile.

Autogenous vaccines, alternatively, made from an culture of an infected animal could be an especially effective way of preventing additional spread within the herd once an outbreak has started.

Some other practical ways of slowing pinkeye spread is paying attention to infected animals and handling them accordingly. If possible, infected animals can be quarantined with plenty of feed bunk space to prevent contact between eyes.

Of course, fly management is again critical to greatly reducing the spread of eye issues within herds or across farms. This includes having an established protocol that discourages the spread and behavior of flies by maintaining a clean environment and having good airflow.

One of the upsides to dealing with pinkeye is it’s a disease that is self-evidence once it reveals itself and has multiple treatment options available. Proper attention to issues and quick response can go a long ways to ensure that issues are promptly dealt with before they become a full outbreak capable of harming production and efficiency.