Ask the Vet

Dr. Ken McMillan, Contributing Columnist

READER: Pink eye is causing a lot of problems for cattlemen in my area. Draxxin used to work. We've tried Draxxin, Naxcel/dex (Naxcel Dexamethasone) in the eyelid, Micotil and other drugs. None work. But, doing nothing, the eye seems to recover after two weeks. Has any company developed a vaccine for every (Moraxella bovis) pink eye infection?

DR. McMILLAN: Pink eye, or infectious bovine keratoconjunctivitis (IBK), is a huge problem and has been estimated to cost the beef industry over $150 million each year.

Pink eye is a highly contagious disease of the cornea of the eyes of cattle and other ruminants usually caused by bacteria in the Moraxella family. Affected animals will develop painful, severe corneal ulcers that can lead to a loss of the eye in some cases and scarring in most cases. These cattle often lose weight, and milk production can be greatly reduced. Fertility can also be reduced. While cattle with reduced vision will be discounted at sale time, the value of bulls and cattle sold for breeding purposes can be decreased even more.

Vaccines may be helpful, but the first step is to identify and address why the cattle are getting pink eye.

Physical irritation, including dust, tall grass and weeds or brush, must be controlled as much as possible. Since sunlight is a huge stressor, cattle need a place to get out of the sun, but that is a double-edged sword since crowding them into small areas can increase spread of the disease.

Viruses, especially IBR, can open the door for infection, so a solid vaccination program for things other than Moraxella is critical. Good nutrition, especially mineral nutrition, is key to maximizing the cattle's immune response. Fly control is critical, especially with face flies, which feed around the eyes and spread the bacteria. And, fly control is hard and getting harder every year. Sanitation to reduce fly breeding grounds needs to be a priority.

A good biosecurity program is critical. In my experience, the most common entry points have been cattle entering the herd without an adequate quarantine or, as in your case, from an adjacent herd.

Draxxin, its generics and long-acting tetracyclines are typically highly effective in treatment. However, when they fail, it is time to culture the eyes to see what is involved and what medications should be the most effective. Your veterinarian can easily do this.

I do not mean to minimize vaccines, but in these cases, it is like closing the gate after the horse has left the barn. In fact, getting the whole herd up to vaccinate in the heat of summer is stressful on man and beast, and can lead to even more spread of pink eye. Mass treatment is always a tough call, and in each case, the risks versus benefits must be carefully examined.

The other issue to understand with vaccines is there are at least two Moraxella bacteria that can be involved in cattle. Moraxella bovis is the most common in your scenario, but Moraxella bovoculi can also be involved. Currently, there is no commercial combination vaccine available, which is even more reason to culture to see what is involved. Often other organisms may also be involved.

I have never been a huge fan of "pink eye vaccines." Effectiveness in field trials have shown inconsistent results. Timing of vaccine administration can be challenging. The type of Moraxella and even variation in the strains involved can make vaccines less effective since they can vary from farm to farm and from year to year.

If you chose to vaccinate, check with your veterinarian and other producers in your area to see what has worked best for them. This can be another benefit of culturing affected cattle. Organisms cultured from your herd can be used to produce an autogenous vaccine. This process takes time and is more expensive than commercial vaccines but can be much more effective in many cases.

**

-- Please contact your veterinarian with questions pertaining to the health of your herd. Every operation is unique, and the information in this column does not pertain to all situations. This is not intended as medical advice but is purely for informational purposes.

-- These are only my thoughts and general guidelines. Please get with your veterinarian and together develop the best program for your herd.

-- Email Dr. Ken McMillan at vet@dtn.com

[PF_1025]

(c) Copyright 2025 DTN, LLC. All rights reserved.