Pinkeye (infectious keratoconjuntivitis) in cattle is a major concern for the well-being and comfort of the animals as well as performance and efficiency. This bacterial infection of the cornea (clear part of the eye) and conjunctiva (tissue above the cornea and underlying the eyelids) causes severe pain and may lead to temporary blindness. 

What causes it?

There are 2 primary bacteria that can cause pinkeye in cattle. Moraxella bovis, which causes the common summertime pinkeye and Moraxella bovoculi with is more common in confined cattle and seen in all seasons.

What do you see?

The initial clinical sign of a developing infection is pain in one or both eyes as evidenced by squinting and a small amount of watery drainage from the eye. This is closely followed by reddening and swelling of the inside of the eyelids and whitening of the cornea of the eye. 

What predisposes cattle to get pinkeye?

There are mechanical and nutritional factors that increase the likelihood of contracting pinkeye, assuming the bacteria are present in your herd or neighboring cattle. 

Mechanical- factors that irritate the eyes

1. Flies- face flies serve as a major source of irritation to the eyes as well as a vector to transmit bacteria from animal to animal

2. Dust- eyes can be irritated from dusty conditions, the irritation causes increased tearing (weeping) from the eyes which also attracts more flies

3. Corneal abrasion- cattle grazing through tall old grass causes abrasion to the cornea leading to more weeping and giving an avenue for bacteria to invade

4. Sunlight- bright summer sun, especially in white faced cattle with no pigment around the eyes can be a source of irritation

Nutritional- certain nutrients are necessary to maintain eye health

1. Vitamin A- normally sufficient in cattle grazing lush green pastures but can be deficient in midsummer pastures that have poor regrowth

2. Vitamin E- a similar situation to Vitamin A

3. Zinc

4. Iodine

What steps can I take to prevent pinkeye?

1. Fly control- using oilers, strips or canvas bullets charged with mineral oil infused with an essential oil helps to control face flies. Naturally, I like Dr. Sarah’s Shoo-fly mixed in mineral oil in oilers and at the mineral feeders. Pyganic is an OMRI approved natural pyrethrum that can also be used in oilers or applied directly to the animal. For those of you not organic the use of permectin containing pour-ons, such as Ultra-Boss every 2-3 weeks provides good protection

2. Clip pastures where possible to remove old dead growth.

3. Supplementation

• Feeding kelp or a high quality sea salt/mineral such as Sea-90 Ocean Mineral helps maintain iodine and other trace mineral levels.

• Additional Vitamin A & E supplements during periods of poor pasture growth.

• Feeding a high quality mineral containing a readily available source of zinc, such as zinc methionine or zinc amino acid complex.

• Feeding a source of garlic as a means to help control flies.

4. Vaccines- there are many strains of the bacteria Moraxella bovis, each of which are unique immunologically, vaccines only contain certain strains and if the strains don’t match the profile on your farm the vaccine may be of limited value. Vaccinations need to be done at least 1 month prior to the pinkeye season

5. Homeopathic nosodes- used in the face of an outbreak or prior to the season these orally administered pills have shown a benefit in my experience. An added advantage is the ability to group administer in a common water source, such as a stock tank. If interested in the nosodes, please contact Dr. Tom.

How do I treat a pinkeye?

Treatment success depends on stage of disease progression when treatment is first started. Treatment when the eye is weeping, eyelids are closed and cornea is still clear can prevent further deterioration. Treatment after the cornea is while will not speed up the hearing process. It will help in reducing the pain, decreasing transmission to other animals and preventing a ulceration and long term blindness.

1. Dr. Paul’s Super Wound Spray is my preferred topical product. When I use it in the early stages I have seen reversal of symptoms with 1 or 2 days of use. Often this can be used when animal are at a bunk or feeding area without catching individual animals
2. If possible, moving affected animals to a separate pen with shade makes them more comfortable. Affected animals are sensitive to sunlight and having a feed source that is easy to access will keep intakes up. 
3. Fly control is important to reduce incidence of transmission to other animals
4. Applying a patch over affected eyes helps to reduce sensitivity to the light and keeps flies away. I rarely do this as it precludes being able to observe the eye as it heals and the option of treating the eye.
5. Because of the painful nature of any eye irritation, I choose to use Dr. Paul’s Will-John Tincture orally if it is easy to restrain animals without undo stress. 
   
6. If the choice is made to use antibiotics there are some that are labeled for pinkeye. Draxxin and LA 200 are two that are commonly used. These are prescription products that need to be sourced through your veterinarian.

The purpose of this blog was to inform you of the multitude of factors that contribute to pinkeye outbreaks in your herd.  The objective of all the control methods is to minimize the number of animals affected and the severity of disease in the ones that get infected.  

You must work with your veterinarian to access prescription products and to use alternative products under a Valid Client Patient Relationship (VCPR).