Taking a stand against pinkeye requires a three-pronged approach that includes vaccination, fly control and environmental management. Pinkeye is a complex disease that requires a complete control/prevention program to minimize associated losses. Like a three-legged stool, leaving out any of these key elements can bring down your entire control program.
The first leg of control is vaccination. Pinkeye is caused when bacterial organisms such as Moraxella bovis infect the surface and fluids of the eye. Pinkeye vaccines stimulate the production of antibodies in tears that bathe the eye, in an attempt to help control infection, thereby reducing the severity of lesions.
Advanced planning is required because animals should be vaccinated three to six weeks prior to the onset of pinkeye season to allow development of immunity. Keep in mind that there are many different strains of Moraxella bovis, in addition to evolving bacteria, that can cause pinkeye, so it is a good idea to work with your veterinarian or animal health provider to identify a vaccine effective against the widest variety of common infectious strains and isolates possible.
Stop the flies
Even with a strong defensive plan, pinkeye problems can still spread rapidly due to the pesky contact of flies that transport the bacteria from the eyes of one animal to another. As the second leg of pinkeye management, fly control should be the key focus for dairy farmers during spring, summer and fall. Face flies can travel significant distances between herds. These flies can potentially expose herds to different strains of Moraxella bovis. This is why vaccination with a broad-spectrum pinkeye vaccine and fly control are such critical legs of the pinkeye prevention stool.
Effective fly control requires customization to your production system. So whether you need to evaluate your current fly control program or start a new one, here are some best management practices to consider:
- Treat animals of all ages and their premises with an insecticide.
- Use products that are effective, long-lasting and easy to administer.
- For calves and cows, apply a low-volume pour-on for rapid knockdown of the existing fly population.
- For growing replacement heifers, apply two ear tags in addition to a low-volume pour-on insecticide.
- Use an insecticide on the animal's premises, such as a microencapsulated product, that delivers superior, long-lasting control on a wide variety of surfaces in and around livestock facilities.
- Use additional fly control measures as necessary, such as back-rubbers, oilers and other devices that can be used on pasture or in the milking parlor as cows exit the facility.
- Eliminate organic debris such as wet/rotting hay, straw, feed, silage and manure. These are ideal breeding grounds for stable flies.
- If you believe a product is not working, contact the manufacturer and your animal health provider to discuss the situation and get some help.
- Reapply insecticides throughout the fly season, and always follow label directions.
Manage the environment
The third leg in pinkeye management is environmental management practices, such as pasture mowing, dust control and man-made or natural shades. External factors increase pinkeye prevalence as well. Ultraviolet light, pollen, seed heads and dust can cause eye irritation. This irritation allows infectious pinkeye organisms to attach to the surface of the eye.
These environmental factors can also cause the eye to tear. Tearing, watery eyes can attract flies which feed on the watery exudates from the eye and surrounding tissue. Remember, since face flies travel from animal to animal, they can rapidly spread Moraxella bovis throughout the herd, thereby dramatically increasing the incidence of pinkeye in a short amount of time.
Ultimately, controlling pinkeye requires a planned attack. And like that three-legged stool, pinkeye control requires three important elements to work well – vaccination, fly control and environmental management. Vaccinate to bathe the eye with protective antibodies, control flies to combat the spread of pinkeye, and manage the environment to limit the external challenges that contribute to pinkeye. There are several different management tools that you can use to minimize the effect of this disease in your herd. Contact your animal health provider to determine appropriate tools and the timing of implementation for your herd and region.
Dr. Norman Stewart is a Manager of Dairy Technical Services for Intervet/Schering-Plough Animal Health. He lives in Illinois. For more information, e-mail Dr. Stewart at firstname.lastname@example.org.