Infectious bovine keratoconjunctivitis (IBK) – or pinkeye – causes painful inflammation in all cases, permanent corneal scarring in some cases, and can lead to blindness in the most severe cases. In dairy cattle, pinkeye can negatively impact milk production and performance. Treatment costs including antibiotics, labor, discarded milk, costs associated with culled animals, etc. average hundreds of dollars per case.1
Pinkeye prevention is critical to keep herds healthy and productive, but it is also a frustrating and challenging effort. The incidence and severity of pinkeye may vary from year to year in the same operation, with no apparent reason why.
While pinkeye has been studied for more than a century, we are still learning about the disease. We do know that corneal damage is generally necessary for pinkeye to develop.2,3 Experts agree there is no silver bullet when it comes to preventing pinkeye, and all three elements of the disease triangle (Figure 1) – host, pathogen and environment – need to be considered.
Figure 1. Pinkeye disease triangle
To successfully prevent IBK, implement environmental management efforts to minimize causes of eye irritation, along with vaccination and fly control practices. Explore the importance of each of these areas below and learn how you can improve your pinkeye prevention plan.
Vaccination
Pinkeye vaccines help ensure that animals are prepared for the challenge, limiting infection and reducing lesions by stimulating antibody production. Vaccinate animals at least three weeks prior to pinkeye season for the best protection. Depending upon the age at which calves are affected, vaccination timing can be challenging due to potential interference with vaccination from colostral antibodies in young calves. Producers should work with their veterinarian to determine the optimal dose timing that works within their operation.
Moraxella bovis, Moraxella bovoculi, and Mycoplasma bovoculi are commensal bacteria species commonly present in the bovine eye. M. bovis is known to cause IBK, but a recent study found that cases often also involve Moraxella bovoculi.4
The ability of M. bovoculi to attach to the cornea seems rather weak, however M. bovoculi has spicules that enable it to attach to M. bovis quite well.5 If M. bovis is attached to the cornea, M. bovoculi may then overgrow it.5
Broad-spectrum vaccines are typically effective against multiple infectious M. bovis strains. However, vaccinating against both M. bovis and M. bovoculi may afford better protection.
As always, discuss all vaccination decisions with your veterinarian.
Fly control
Female face flies (Musca autumnalis) stimulate the production of ocular secretions that they feed on with rasp-like mouth parts, damaging the surface of the cornea. Because surface damage is necessary for M. bovis to attach to the cornea, controlling face flies is critical to prevent IBK.
There are several options for fly control. Choose methods that are effective, long-lasting and easy to use. Popular fly control methods include fly tags, pour-ons, sprays, dust bags and back rubbers.
Timing is important when it comes to fly control. For example, applying fly tags too early may result in the product running out before the end of the season. Conversely, if fly control measures are implemented too late in the season, the fly population may already be too great for them to be effective. In these cases, apply a low-volume pour-on for rapid knockdown of the existing fly population.
Environmental management
Many environmental factors predispose animals to IBK by causing eye irritation and damage. In addition to female face flies, examples of what may cause this damage include dust, sawdust, sand, sunlight (UV radiation), grazing in tall grass, and young animals eating from large round bales, among other factors.
As an example, I once visited a heifer development facility where the herdsman complained of an ongoing IBK problem. I noticed trucks frequently driving on a dirt road along the western border of the facility, kicking up significant amounts of dust. In this case, dust was a likely cause of corneal damage, and watering the road was a potential simple solution to help prevent pinkeye.
Evaluate your operation and facilities to identify potential sources of corneal damage and then work to minimize them. In general, if you experience eye irritation, it’s likely that your cows do too.
Follow expert advice
While there are still many unanswered questions regarding pinkeye, experienced experts are working tirelessly on this topic. Recently, renowned veterinarians and researchers – all well-versed in the science of pinkeye – participated in a roundtable discussion to dig deeper into pinkeye and how to reduce its impact. The report summarizing this roundtable explains these perspectives, how to get the most out of a vaccination strategy, and strategies for preventing pinkeye.
Your local veterinarian plays an important role in providing guidance on the best way to approach pinkeye control. Work with your veterinarian to create the best pinkeye management plan for your operation, incorporating the best approaches for fly control, vaccination and environmental management.
Getting your plan of attack in place and implemented will help in maintaining animal health, welfare, productivity and profitability.