Don't let pinkeye make you see red

As we approach the hot summer months, more and more producers are dealing with the nuisance of pinkeye. Pinkeye is a highly infectious bacterial disease. Although pinkeye is nonfatal, it costs cattle producers over $150 million per year. These expenses result from decreased weight gain, reduced milk production and treatment costs. Additionally, infected animals are worth less at sale time. Pinkeye is second only to scours/diarrhea in terms of diseases affecting calves.

Causes of Pinkeye

While the bacteria Moraxella bovis is the main causative agent, other microorganisms such as Chlamydia, Mycoplasma and Acholeplasma or viruses such as the IBR virus can either predispose the eye to pinkeye or make the disease more severe.

Irritants to the eye make it more susceptible to development of pinkeye. Irritants include ultraviolet light, plants, dust and flies. Cattle lacking pigment around the eyes tend to be more susceptible to UV light irritation resulting in inflammation and infection. Plants provide irritation though release of pollen and chaff and also physical irritation through poking, especially in the seedhead stage. Dust is usually not a major factor for pastured cattle and is more relevant in confinement. Several species of flies (face flies, stable flies and house flies) also provide irritation and can actively carry the bacteria from animal to animal. Face flies have been shown to remain infected with M. bovis for up to 3 days after feeding on infected secretions. Pinkeye can also spread via physical animal to animal contact, especially in close quarters.

If left untreated, ulcerations can occur and can result in loss of the eye. This is particularly troubling for bull calves, as bulls rely on visual cues for detecting cows in heat. Research has shown that weaning weights can be reduced as much as 60 lbs per calf. Additionally, cattle with pinkeye are discounted an average of $11.75 per CWT at the sale barn.


M. bovis is susceptible to many antibiotics including oxytetracycline, penicillin and sulfonamides. Treatment involves handling cattle and either delivering an IM or SubQ injection or other direct eye treatments. As always, consult with your veterinarian prior to treatment. It bears mentioning that the new FSMA regulations will require prescription by a veterinarian for these drugs in the not so distant future. These drugs are available overthe- counter as it stands today.


Given that treatment is expensive, prevention becomes even more important. The first means of prevention is to never bring infected animals to your farm in the first place through careful inspection prior to purchase. Also, a standard quarantine for new animals will help identify carriers and allow them to be treated prior to introduction into the main herd. Commercial vaccines are available, (Consult with your veterinarian before embarking on a vaccination program.) but even vaccine manufacturers recommend environmental management and fly control in addition to vaccination. Other methods to help prevent pinkeye include proper mineral and vitamin nutrition including adequate levels of zinc and vitamin A for eye integrity. Additionally, regular clipping of pastures will not only remove seedheads from irritating animals’ eyes, but will also increase the relative nutritional value of your pastures by increasing vegetative growth. And finally, fly control will go a long way to keep pinkeye from spreading throughout your herd.

Feed Through Fly Control

Rabon® Oral Larvicide is a nontoxic feed-through larvicide. Rabon interrupts the lifecycle of the target flies by preventing larvae from developing into adults. Rabon is not absorbed by the animal and safely passes through the digestive tract. There is no slaughter withdrawal and Rabon can be safely fed to lactating and pregnant cows. Rabon remains in the manure where it kills developing larvae on contact. Rabon is the only feed-through fly control product to control horn flies, face flies, stable flies and house flies. As mentioned earlier, face flies, house flies and stable flies are known to transmit the M. bovis bacterium from cow to cow. Reducing the number of these flies will cut transmission, especially in a pasture situation. Another advantage of Rabon is that it can be utilized for fly control for horses as well as cattle. Rabon is environmentally safe and has no adverse effect on the dung beetle or other beneficial insects.

SWEETLIX offers a wide variety of products containing Rabon for your convenience. Additionally, each of these products will deliver essential nutrients, including zinc and vitamin A which are so important for eye health. The SWEETLIX® Rabon® Pressed Block and SWEETLIX® Pest-A-Side Pressed Block with Rabon® are compact and easy to use. Just place them where cattle congregate. No special feeders or bunks needed. SWEETLIX® 6% CopperHead® with Rabon® loose mineral combines the superior copper nutrition of CopperHead® with the fly control benefits of Rabon. SWEETLIX® EnProAl® Rabon® Supplements are available in convenient 200-lb tubs and are ideal for livestock that aren’t checked on a daily basis. SWEETLIX has a product to fit any size operation and any production scenario.


In summary, pinkeye is a costly bacterial disease for the cow-calf producer. Anything that irritates or damages the eye makes it more susceptible to infection by the M. bovis bacterium. Treatment involves costly antibiotics and stressful cattle handling, thus prevention is preferred. Prevention of pinkeye can be achieved through a combination of vaccination, management and fly control. SWEETLIX products containing Rabon Oral Larvicide offer the superior fly control of Rabon along with the proven intake and superior nutrition of SWEETLIX.

To learn more visit your local SWEETLIX dealer or call 1-87-SWEETLIX to find the self-fed fly control supplement that works best for you.


Rabon® is a registered trademark of Bayer HealthCare, LLC