How to Treat Pink Eye in Cattle: Antibiotics & Patches

Pink eye in cattle, formally called infectious bovine keratoconjunctivitis (IBK), responds best to a combination of antibiotic therapy and physical protection of the affected eye. A systematic review of randomized trials found that most antibiotic treatments significantly improved healing compared with placebos, with the largest differences appearing roughly one to two weeks after treatment.¹ Eye patches, meanwhile, have been shown in controlled trials to cut median healing time by several days. The practical challenge is getting the right treatment onto the right animal fast enough, because untreated pink eye can permanently scar the cornea and costs real weight gain at the scales.

What Causes Pink Eye and Why Speed Matters

The primary culprit behind IBK is the bacterium Moraxella bovis, though a related species, Moraxella bovoculi, is increasingly recognized in outbreaks as well.² These bacteria produce toxins that break down the corneal surface, starting as excessive tearing and sensitivity to light and progressing to a visible white or cloudy ulcer. Face flies (Musca autumnalis) are a major vector. Research has shown that M. bovis can survive on a fly’s wings and legs for up to three days, and since face flies feed persistently around the eyes, they shuttle bacteria from one animal to the next with brutal efficiency.³

Speed matters because the disease is self-reinforcing. An infected eye weeps more, which attracts more flies, which spread bacteria to herdmates. Left untreated, ulcers can perforate the cornea and cause permanent blindness. Even in animals that eventually recover on their own, the economic toll is steep. Classic research on Hereford calves found that animals affected with pink eye during the preweaning period weighed roughly 36 to 40 pounds less at 205 days than unaffected calves, and bulls with a history of pink eye also gained less weight in the postweaning period.⁴ That kind of weight difference translates directly to money at sale time, which is why treating early and aggressively is worth the labor.

Antibiotic Options and How They Are Used

Several antibiotics have been studied in randomized clinical trials for IBK, including oxytetracycline, florfenicol, ceftiofur, procaine penicillin G, tilmicosin, and benzathine cloxacillin.⁵ The evidence, taken together, shows that antibiotics reduce healing time for corneal ulcers compared with no treatment. The strongest separation between treated and untreated animals tends to show up about one to two weeks after treatment is given.¹

In practice, producers and veterinarians choose among three main delivery routes depending on the animal, the setting, and the severity of the lesion:

Subconjunctival injection: A small volume of antibiotic, often penicillin, is injected directly under the membrane lining the eye. This delivers a high local concentration right at the infection site. It is considered highly effective by producers who have used it, though it requires restraining the animal and some skill with the needle placement.
Injectable (systemic) antibiotics: Long-acting oxytetracycline or tulathromycin given intramuscularly treats the infection from within. This is often the most practical choice in range conditions where you may only get one chance to handle the animal. A single injection of long-acting oxytetracycline is one of the most commonly studied and widely used protocols.
Topical preparations: Ointments, sprays, and powders applied directly to the eye. In a large Australian survey of cattle farmers, topical pinkeye ointments were the most frequently used treatment overall, with eye patches and sprays also ranking high.⁶ Topicals can work well for mild cases but usually need repeated application, which means catching and restraining the animal more than once.

Head-to-head comparisons between specific antibiotics are still surprisingly limited. Most published trials compared an antibiotic against a placebo or untreated control, not against another antibiotic. The systematic reviews that exist have called for more direct-comparison trials, which means you and your veterinarian are often choosing based on practical factors: the drug’s withdrawal time before slaughter, whether you need a single dose or multiple doses, local drug availability, and cost.¹

Eye Patches and Why They Help

Gluing an opaque patch over the affected eye does two things at once: it blocks UV light from irritating the damaged cornea, and it keeps flies from landing on the weeping eye and spreading bacteria further. A randomized controlled trial on stocker steers found that patched eyes healed faster, with a median healing time of about 10 days compared with 14 days for unpatched eyes. Statistically, patched eyes were roughly 60 percent more likely to have healed at any given follow-up point.⁷

Getting a patch to stay on is the tricky part. Commercial cattle eye patches are typically cloth patches glued to the skin around the eye socket with a veterinary adhesive. In the trial above, researchers found that patches attached with glue alone fell off quickly, so they reinforced the edges with duct tape to improve durability.⁸ Leaving the bottom edge of the patch unattached allows drainage so the eye does not sit in trapped moisture, which could make things worse. Many producers who have used patches and subconjunctival injections rate both as highly effective.⁶

Patches are most practical when you can restrain the animal in a chute, clean and dry the skin around the eye, and apply the patch carefully. They work especially well when combined with an antibiotic treatment at the same handling. The combination makes intuitive sense: the antibiotic attacks the bacteria while the patch protects the healing surface and removes two environmental stressors (UV and flies) simultaneously.

Pain Relief Is Worth Considering

Pink eye is painful. The cornea is one of the most nerve-rich tissues in the body, and a large ulcer on it will cause an animal to squint, hold its head down, and go off feed. Despite this, pain management in IBK has historically gotten less attention than the antibiotic decision. Non-steroidal anti-inflammatory drugs like meloxicam or flunixin can reduce both pain and inflammation.⁹ An animal in less pain eats more, which supports healing and mitigates the weight loss that pink eye causes.

Talk to your veterinarian about adding an anti-inflammatory when you treat a case, especially a severe one. In many countries, the use of certain pain-relief drugs in food-producing animals requires a prescription and comes with withdrawal periods you need to respect before slaughter. But the welfare benefit and the production benefit both point in the same direction here.

Fly Control as a Front-Line Prevention Tool

Because face flies are the primary shuttle for IBK bacteria between animals, any serious prevention program has to include fly management. Insecticide ear tags, pour-on products, dust bags, and oilers can all reduce fly numbers on cattle. The timing matters: fly pressure peaks in warm, humid months, and outbreaks of pink eye track closely with face fly populations. Reducing fly loads does not eliminate pink eye, but it slows the rate at which the disease rips through a herd.

Some producers rely heavily on fly control as part of their treatment strategy, too. In the Australian survey mentioned earlier, fly control ranked among the top five most commonly used interventions for active cases.⁶ This makes sense on paper: even after you have treated an animal’s eye, that eye continues weeping for days, and every fly that visits spreads bacteria to the next calf. Tall grass and weeds in pastures are another irritant, physically scratching the cornea and making it easier for bacteria to colonize, so mowing or managing pasture height before peak fly season is a practical step that addresses two risk factors at once.

The Vaccine Problem

Vaccines for pink eye exist, but the evidence for their effectiveness is genuinely discouraging. A five-year randomized trial compared a commercial vaccine, a custom-made (autogenous) vaccine, and a sham control. Calves given the autogenous vaccine had a slightly lower cumulative incidence of pink eye over the study period, but the difference was not statistically significant. Interestingly, the autogenous formulation did produce a stronger antibody response, yet those antibody levels did not correlate with actual protection from the disease.¹⁰

A separate study went further, conducting its own meta-analysis of previous vaccine trials and concluding that autogenous M. bovis vaccines have consistently failed to offer meaningful protection across published studies. The researchers noted that given the positive publication bias in scientific literature (studies showing a benefit are more likely to be published), the fact that none of the published studies reported effectiveness was especially telling.¹¹

This does not mean vaccines will never work. The disease is caused by multiple bacterial strains and species, and the strains circulating in one herd may differ from those in another, which complicates vaccine design. But at present, vaccination should not be counted on as a reliable prevention strategy. You are better served investing that time and money in fly control, early detection, and prompt treatment.

Growing Antibiotic Resistance

Like many bacterial diseases of livestock, pink eye pathogens are showing signs of reduced antibiotic susceptibility. A recent analysis of isolates found that M. bovoculi in particular showed reduced susceptibility to fluoroquinolones, tetracyclines, and phenicols, while M. bovis remained relatively more susceptible.² Broader reviews of IBK management have flagged rising antibiotic resistance as one of the central challenges facing current control strategies.¹²

What this means practically: tetracycline, the workhorse antibiotic for pink eye in many operations, may not remain as reliably effective in the years ahead, particularly against M. bovoculi. Working with your veterinarian to identify the specific bacteria in an outbreak, rather than defaulting to the same antibiotic every time, is becoming more important. Judicious use of antibiotics, including reserving certain drug classes for severe or non-responsive cases, helps slow resistance development across the industry.

Hypochlorous Acid Spray as an Alternative Therapy

For producers looking for non-antibiotic options, topical hypochlorous acid spray has shown some promise. In an experimental challenge study, calves whose eyes were sprayed twice daily with a commercial hypochlorous acid product (a dilute antimicrobial solution) had lower pain scores, faster lesion healing, and smaller corneal ulcers compared with untreated controls.¹³ The catch is that this was a preliminary study using experimentally induced infections, which tend to be more uniform than what happens in the pasture, and the spray required twice-daily application. That frequency is realistic in a feedlot or drylot setting but impractical on rangeland where you may not see the animal again for days. Still, for small operations, show cattle, or dairy calves where frequent handling is feasible, topical sprays offer a useful tool that does not contribute to antibiotic resistance.

Breed and Pigmentation Differences

Not all cattle are equally vulnerable to pink eye, and the single biggest genetic risk factor is eyelid pigmentation. Breeds with little pigment around the eyes, most famously Herefords and Hereford crosses, are at significantly higher risk. Research into the genetics of eyelid pigmentation in Herefords has confirmed that low pigment is a well-established risk factor for IBK as well as for ocular squamous cell carcinoma, though the precise genetic and biological pathways behind this relationship are still being worked out.¹⁴

The mechanism likely involves UV damage. Pigmented skin around the eye filters UV radiation, protecting the corneal surface and the conjunctiva. Without that pigment, the tissues are more easily irritated, and damaged tissue is easier for bacteria to colonize. If you run Herefords or other light-pigmented breeds, this is one more reason to be aggressive with fly control, shade provision, and early treatment. Selecting for more eyelid pigmentation within a herd is a long-term genetic strategy that some breeders actively pursue.

Nutrition and Immune Readiness

An animal’s ability to fight off IBK depends partly on its nutritional status, and vitamin A deserves special mention. Vitamin A is essential for maintaining healthy epithelial tissues, including the corneal surface, and for normal immune function. Hypovitaminosis A in calves has been linked to secondary bacterial infections and a range of pathological damage.¹⁵ Cattle on lush green pasture typically get plenty of vitamin A precursors from beta-carotene in the forage. But cattle on dry, mature grass, harvested hay that has been stored for months, or high-concentrate feedlot rations may be deficient. A simple injectable vitamin A supplement at processing or turnout is cheap insurance, especially heading into the season when pink eye pressure is highest.

Trace minerals like copper, zinc, and selenium also support immune function broadly. While no single mineral supplement is a magic bullet against pink eye, ensuring your herd’s mineral program is adequate removes one more predisposing factor. Think of nutrition as setting the baseline: a well-nourished animal with a strong immune response may clear an early infection before it becomes a clinical ulcer, while a deficient animal is more likely to develop the kind of severe case that requires antibiotics, patches, and multiple handlings.

Putting a Treatment Protocol Together

When you spot an animal with a watery eye, squinting, or a visible white spot on the cornea, the goal is to act within 24 to 48 hours if possible. A reasonable approach for a moderately severe case on pasture might look like this: bring the animal in, administer a long-acting injectable antibiotic such as oxytetracycline or tulathromycin, apply an eye patch with adhesive and reinforcing tape (leaving the bottom open for drainage), and give an anti-inflammatory for pain and swelling. For mild cases caught early, a topical antibiotic ointment alone may suffice, but keep monitoring. For severe cases with a large, deep ulcer or evidence of rupture, get your veterinarian involved immediately; subconjunctival injections and more intensive care may be needed.

Regardless of the treatment you choose, isolating the affected animal or at least checking herdmates daily is smart. One case often signals that conditions are ripe for an outbreak, particularly if fly pressure is high. Re-examine treated animals at around seven to ten days. If the ulcer is not shrinking or is getting worse, a second round of treatment or a different antibiotic may be warranted. Chronic or non-healing ulcers sometimes involve secondary infections or complications that need a different approach entirely.

Record keeping helps over time. Tracking which animals get pink eye, which treatments you used, and how quickly cases resolved lets you and your veterinarian spot patterns: maybe a particular pasture group gets hit every July, or maybe cases treated with one antibiotic resolve faster than those treated with another. These kinds of on-farm observations, informal as they are, complement the published science and help you refine your protocol for your specific herd and environment.

1
Animal Health Research Reviews. A systematic review and meta-analysis of the antibiotic treatment for infectious bovine keratoconjunctivitis: an update
2
PubMed. Genetic diversity, virulence genes, and antimicrobial resistance of Moraxella bovoculi and Moraxella bovis from infectious bovine keratoconjunctivitis
3
Journal of Economic Entomology. Investigations on Transmissability of Moraxella bovis by the Face Fly
4
Journal of Animal Science. Impact of Pinkeye (Infectious Bovine Kerato-Conjunctivitis) on Weaning and Postweaning Performance of Hereford Calves
5
Animal Health Research Reviews. A review of randomized clinical trials reporting antibiotic treatment of infectious bovine keratoconjunctivitis in cattle
6
Preventive Veterinary Medicine. Perceptions and practices of Australian cattle farmers for the treatment of pinkeye (infectious bovine keratoconjunctivitis)
7
PubMed Central. Effects of eye patches on corneal ulcer healing and weight gain in stocker steers on pasture: a randomized controlled trial
8
Translational Animal Science. Effects of eye patches on corneal ulcer healing and weight gain in stocker steers on pasture – Section: MATERIALS AND METHODS
9
Journal of Veterinary Physiology and Pathology. The Management and Treatment of Keratoconjunctivitis in A 6-Month-Old Lamb: A Case Report
10
PubMed Central. A Five Year Randomized Controlled Trial to Assess the Efficacy and Antibody Responses to a Commercial and Autogenous Vaccine for the Prevention of Infectious Bovine Keratoconjunctivitis
11
Journal of Veterinary Internal Medicine. A Randomized Clinical Trial Evaluating a Farm-of-Origin Autogenous Moraxella bovis Vaccine to Control Infectious Bovine Keratoconjunctivitis (Pinkeye) in Beef Cattle
12
PubMed Central. Bovine ocular microbiome: the next frontier in managing Pinkeye in cattle
13
The Bovine Practitioner. Preliminary evaluation of hypochlorous acid spray for treatment of experimentally induced infectious bovine keratoconjunctivitis
14
PubMed. Transcriptomic analysis of eyelid pigmentation in Hereford cattle
15
PubMed Central. Hypovitaminosis A coupled to secondary bacterial infection in beef cattle