Cattle Corneal Ulcer and Infectious Keratoconjunctivitis: Examination, Treatment, and Outbreak Control

This article provides veterinarians with a clinical framework for diagnosing and managing corneal ulcers and infectious bovine keratoconjunctivitis (IBK) in cattle. The content focuses on examination techniques, medical and surgical treatment options, and outbreak control measures based on published evidence. Clinical decisions must be made on a case-by-case basis, considering individual animal welfare, herd health status, and applicable regulations.

At a Glance: Clinical Decision Guide for Corneal Ulcers and IBK

Clinical Examination and Diagnosis

History and Signalment

Obtain a complete history including onset of clinical signs, number of animals affected, age distribution, and any recent introductions to the herd. IBK is most commonly observed in young cattle, but all ages can be affected. Record environmental factors such as dust, sunlight exposure, and fly populations. Note any previous IBK outbreaks on the premises and vaccination history. The Merck Veterinary Manual provides general guidance on ophthalmic examination approaches in food animals.

Physical Examination

Perform a thorough ophthalmic examination in adequate lighting. Assess both eyes even if only one appears affected. Evaluate for blepharospasm, epiphora, photophobia, and conjunctival hyperemia. Examine the cornea for opacities, edema, vascularization, and ulceration. Document the location, size, and depth of any corneal lesions. The World Organisation for Animal Health provides standards for animal health surveillance that apply to ocular disease monitoring in cattle.

Fluorescein Staining

Fluorescein stain is essential for identifying corneal ulcers. Apply one drop of sterile fluorescein solution to the conjunctival sac and observe under cobalt blue light. A positive stain indicates loss of corneal epithelium. Record the size and shape of the stained area. Use a sterile cotton-tipped applicator to gently roll the stain over the cornea if the animal is uncooperative. The Merck Veterinary Manual describes fluorescein staining as a standard diagnostic procedure for corneal ulceration.

Ulcer Grading

Grade corneal ulcers based on depth and severity. Superficial ulcers involve only the epithelium. Deep ulcers extend into the stroma. Descemetocele occurs when the ulcer reaches Descemet's membrane. Corneal perforation is a surgical emergency. Document the grade in the medical record. The Merck Veterinary Manual provides classification criteria for corneal ulcers in domestic animals.

Diagnostic Testing

Consider corneal cytology and culture in refractory cases or when atypical pathogens are suspected. Collect samples using a sterile swab after topical anesthesia. Submit for aerobic culture and sensitivity testing. Moraxella bovis is the primary bacterial pathogen associated with IBK, but other Moraxella species and secondary invaders may be involved. A review of infectious bovine keratoconjunctivitis published in the Journal of Veterinary Internal Medicine describes the role of Moraxella bovis in IBK pathogenesis.

Medical Treatment

Topical Antibiotics

Topical antibiotic therapy is the mainstay of treatment for corneal ulcers and IBK. Choose an antibiotic based on expected susceptibility patterns. Published studies have evaluated various antibiotics for treatment of IBK. A systematic review and meta-analysis of antibiotic treatment for infectious bovine keratoconjunctivitis provides an update on evidence for different antibiotic classes. The evidence base for treatment of infectious bovine keratoconjunctivitis continues to evolve. The Merck Veterinary Manual lists topical antibiotics as a standard component of IBK treatment protocols.

Subconjunctival Antibiotics

Subconjunctival antibiotic injections provide high local drug concentrations. This route is particularly useful when topical administration is difficult or when deeper infections are present. Administer after topical anesthesia. Use a 25-gauge needle and inject into the subconjunctival space. Record the drug, dose, and injection site. The Merck Veterinary Manual describes subconjunctival antibiotic administration as an effective delivery method for ocular infections in cattle.

Non-Steroidal Anti-Inflammatory Drugs

NSAIDs reduce ocular inflammation and pain. Administer systemically or topically. Monitor for adverse effects, particularly in dehydrated or hypovolemic animals. Record the drug, dose, route, and frequency. The Merck Veterinary Manual includes NSAIDs as part of the therapeutic approach for ocular pain and inflammation in food animals.

Atropine

Topical atropine relieves ciliary spasm and reduces pain associated with corneal ulcers. It also dilates the pupil, which may help prevent synechiae formation. Use with caution in animals with glaucoma. Record the concentration and frequency. The Merck Veterinary Manual describes atropine use for cycloplegia and mydriasis in corneal ulcer management.

Supportive Care

Provide a clean, shaded environment to reduce photophobia and fly irritation. Consider using a fly mask or insect repellent around the eyes. Ensure adequate nutrition and hydration. The World Organisation for Animal Health emphasizes the importance of environmental management in disease control programs for livestock.

Surgical Treatment

Third Eyelid Flap

A third eyelid flap provides mechanical protection for the cornea. This procedure is indicated for deep ulcers, descemetoceles, and after corneal surgery. Perform under sedation and local anesthesia. Suture the third eyelid to the upper eyelid using non-absorbable suture. Remove the flap after 10 to 14 days. The Merck Veterinary Manual describes the third eyelid flap as a surgical option for corneal protection in cattle.

Conjunctival Graft

A conjunctival graft provides vascular support and structural integrity for deep corneal ulcers. This procedure requires advanced surgical skills and is typically performed under general anesthesia. Postoperative care includes topical antibiotics and NSAIDs. The Merck Veterinary Manual lists conjunctival grafts as a surgical option for deep corneal ulcers in large animals.

Tarsorrhaphy

Temporary tarsorrhaphy reduces corneal exposure and promotes healing. Place horizontal mattress sutures through the eyelid margins. Remove sutures after 7 to 10 days. The Merck Veterinary Manual describes tarsorrhaphy as a technique for corneal protection in animals with exposure keratitis.

Enucleation

Enucleation is reserved for non-functional, painful eyes with severe infection or perforation. Perform under general anesthesia. Submit the globe for histopathology if the cause is uncertain. The Merck Veterinary Manual provides indications for enucleation in cattle with end-stage ocular disease.

Outbreak Control

Isolation and Quarantine

Isolate affected animals from the rest of the herd. Quarantine new arrivals for at least 14 days. Monitor all animals for clinical signs. Record the number of new cases daily. The World Organisation for Animal Health provides guidelines for isolation and quarantine procedures in livestock disease control.

Fly Control

Flies are mechanical vectors for Moraxella bovis. Implement an integrated fly control program including insecticide ear tags, pour-ons, and environmental management. Reduce breeding sites by removing manure and standing water. Consider biological control agents such as parasitic wasps. The Merck Veterinary Manual emphasizes fly control as a critical component of IBK prevention programs.

Vaccination

Vaccination against Moraxella bovis may reduce the incidence and severity of IBK. Consult with a veterinary immunologist or epidemiologist for specific vaccine recommendations. Record vaccination dates, product, and route. A review of infectious bovine keratoconjunctivitis published in the Journal of Veterinary Internal Medicine discusses vaccination strategies for IBK control.

Biosecurity

Implement biosecurity measures to prevent introduction and spread of IBK. Use separate equipment for affected animals. Disinfect handling facilities between groups. Limit visitor access to the herd. The World Organisation for Animal Health provides biosecurity standards for livestock operations to prevent disease transmission.

Records and Measurements

Individual Animal Records

Maintain individual animal records including identification, date of onset, clinical findings, treatment administered, and outcome. Record any adverse reactions to treatment. Use a standardized form to ensure consistency. The World Organisation for Animal Health emphasizes record-keeping as essential for animal health surveillance and disease control.

Herd-Level Records

Track herd-level parameters such as incidence rate, prevalence, and case fatality rate. Record environmental conditions and management changes. Use this data to evaluate the effectiveness of control measures. The World Organisation for Animal Health provides frameworks for herd-level disease monitoring in livestock populations.

Treatment Response

Monitor treatment response daily. Record changes in corneal opacity, ulcer size, and pain levels. If no improvement is seen within 48 hours, reassess the diagnosis and treatment plan. The Merck Veterinary Manual recommends re-evaluation of non-responsive cases to rule out complications or resistant infections.

Common Failure Patterns

Incomplete Treatment

Failure to complete the full course of treatment is a common cause of relapse. Ensure that owners understand the importance of completing the prescribed regimen. Provide written instructions. The Merck Veterinary Manual notes that incomplete therapy contributes to treatment failure in ocular infections.

Inadequate Fly Control

Without effective fly control, reinfection is likely. Evaluate the fly control program and make adjustments as needed. Consider using multiple control methods. The Merck Veterinary Manual identifies fly control as a key factor in IBK prevention and outbreak management.

Delayed Diagnosis

Delayed diagnosis allows ulcers to progress to deeper layers. Educate owners to seek veterinary care at the first sign of ocular disease. Provide training on recognizing early clinical signs. The World Organisation for Animal Health emphasizes early detection as critical for effective disease control in livestock.

Antibiotic Resistance

Antibiotic resistance in Moraxella bovis has been reported. A study on antimicrobial susceptibility of Moraxella bovis found varying resistance patterns. Another study on antibiotic sensitivity of an Argentine strain collection of Moraxella bovis also documented resistance. A more recent study on drift of antimicrobial resistance of bacterial pathogens of the Moraxella group indicates ongoing changes in susceptibility. Culture and sensitivity testing is recommended when initial treatment fails. The American College of Veterinary Internal Medicine provides resources on antimicrobial stewardship in veterinary practice.

Welfare and Safety Context

Pain Management

Corneal ulcers and IBK are painful conditions. Provide adequate analgesia using NSAIDs and atropine. Consider using a local anesthetic block for surgical procedures. Monitor for signs of pain and adjust treatment accordingly. The World Organisation for Animal Health includes pain management as a component of animal welfare standards in livestock production.

Zoonotic Risk

Moraxella bovis is not considered a significant zoonotic pathogen. However, standard hygiene practices should be followed when handling affected animals. Wash hands after contact. The World Organisation for Animal Health provides guidelines for zoonotic disease prevention in livestock handling.

Regulatory Considerations

All treatments must comply with local regulations regarding veterinary medicines. Record all treatments in the medical record. Observe withdrawal periods for meat and milk. The American College of Veterinary Internal Medicine provides guidance on regulatory compliance in veterinary therapeutics.

Professional Escalation Criteria

Urgent Escalation

Refer to a veterinary ophthalmologist if any of the following are present:

• Corneal perforation
• Descemetocele
• Deep stromal ulcer not responding to medical therapy
• Suspected intraocular infection
• Glaucoma

The Merck Veterinary Manual identifies these conditions as requiring specialist referral for optimal outcomes.

Routine Escalation

Consider referral for:

• Recurrent ulcers
• Atypical clinical presentation
• Diagnostic uncertainty
• Need for advanced imaging

The American College of Veterinary Internal Medicine provides resources for identifying cases that benefit from specialist consultation.

Treatment Selection Framework: Matching Therapy to Ulcer Grade and Herd Status

Selecting the appropriate treatment for corneal ulcers and infectious bovine keratoconjunctivitis requires a systematic approach that accounts for ulcer severity, individual animal factors, herd outbreak status, and available resources. A structured decision framework helps veterinarians avoid under-treatment of deep ulcers and over-use of antibiotics in superficial cases where environmental management may suffice. This section provides a practical treatment selection algorithm, a record system for tracking outcomes, troubleshooting methods for non-responsive cases, and a comparison of delivery routes for ocular medications.

Treatment Decision Algorithm by Ulcer Grade

The following algorithm guides treatment selection based on fluorescein staining results and ulcer depth assessment. Each grade corresponds to specific therapeutic interventions and monitoring intervals.

Grade 1: Superficial Epithelial Ulcer

A superficial ulcer involves only the corneal epithelium with no stromal involvement. Fluorescein stain shows a discrete area of uptake without pooling or edge thinning. These ulcers typically heal within 3 to 7 days with appropriate management.

Treatment protocol:

• Topical broad-spectrum antibiotic ointment or solution applied three to four times daily for 5 to 7 days
• Topical atropine 1% solution once daily for 2 to 3 days if blepharospasm is present
• Systemic NSAID (flunixin meglumine or meloxicam) for 2 to 3 days
• Fly control measures implemented immediately
• Re-examine at 48 to 72 hours to confirm healing

If the ulcer has not reduced in size by 50% at 72 hours, re-evaluate for deeper involvement or secondary infection. The Merck Veterinary Manual notes that most superficial corneal ulcers in cattle respond to topical antibiotic therapy alone when environmental factors are controlled.

Grade 2: Superficial Stromal Ulcer

A superficial stromal ulcer extends into the anterior stroma but involves less than 50% of corneal thickness. Fluorescein stain shows a broader area of uptake with mild stromal edema. These ulcers require more aggressive therapy and closer monitoring.

Treatment protocol:

• Topical antibiotic solution applied four to six times daily for 7 to 10 days
• Subconjunctival antibiotic injection (ceftiofur or oxytetracycline) at initial examination
• Topical atropine 1% solution once or twice daily for 5 to 7 days
• Systemic NSAID for 3 to 5 days
• Consider third eyelid flap if the animal is in a dusty or high-fly environment
• Re-examine at 48 hours to assess progression

If the ulcer shows no improvement or has deepened at 48 hours, escalate to Grade 3 protocol and consider surgical intervention. A systematic review and meta-analysis of antibiotic treatment for infectious bovine keratoconjunctivitis published in Animal Health Research Reviews provides evidence that subconjunctival antibiotics improve outcomes in stromal ulcers compared to topical therapy alone.

Grade 3: Deep Stromal Ulcer or Descemetocele

A deep stromal ulcer involves more than 50% of corneal thickness. Descemetocele appears as a clear or dark spot at the ulcer base where Descemet's membrane is exposed. These are surgical emergencies requiring immediate intervention.

Treatment protocol:

• Subconjunctival antibiotic injection immediately
• Topical antibiotic solution every 2 to 4 hours if possible
• Topical atropine 1% solution twice daily
• Systemic NSAID for 5 to 7 days
• Systemic antibiotic (ceftiofur or oxytetracycline) for 5 to 7 days
• Third eyelid flap or conjunctival graft performed within 24 hours
• Hospitalize or confine to a clean, shaded area
• Re-examine daily for the first 3 days

If corneal perforation is present or imminent, refer to a veterinary ophthalmologist immediately. The Merck Veterinary Manual identifies deep stromal ulcers and descemetoceles as indications for surgical intervention in cattle.

Grade 4: Corneal Perforation

Corneal perforation is a sight-threatening emergency. The anterior chamber may be shallow or flat, and uveal tissue may prolapse through the defect.

Treatment protocol:

• Immediate surgical repair under general anesthesia
• Conjunctival graft or corneal graft
• Subconjunctival and systemic antibiotics
• Systemic NSAID and atropine
• Intensive postoperative care including topical medications every 2 to 4 hours
• Enucleation if the eye is non-viable or severely infected

The Merck Veterinary Manual states that corneal perforation in cattle carries a guarded prognosis for vision and requires prompt surgical intervention.

Delivery Route Comparison for Ocular Medications

Choosing between topical, subconjunctival, and systemic routes depends on ulcer severity, animal temperament, and available facilities. Each route has distinct advantages and limitations.

Topical Administration

Topical antibiotics and atropine are the most commonly used delivery methods for corneal ulcers and IBK. Advantages include direct application to the affected tissue, minimal systemic absorption, and low cost. Limitations include difficulty in administration to uncooperative animals, variable drug retention time, and the need for frequent application.

Ointments provide longer contact time than solutions but may blur vision. Solutions are easier to apply but drain more quickly. The Merck Veterinary Manual recommends using ointments for overnight treatment and solutions for daytime applications when frequent dosing is possible.

Practical considerations for topical administration:

• Restrain the animal in a head gate or chute
• Clean the periocular area before application
• Apply to the conjunctival sac, not directly on the cornea
• Massage the eyelid gently to distribute the medication
• Record the time of each application

Subconjunctival Injection

Subconjunctival antibiotic injection provides high local drug concentrations that persist for 24 to 48 hours. This route is particularly useful when topical administration is difficult or when deeper infections are present. Advantages include sustained drug release, bypassing the tear film barrier, and reduced frequency of handling.

Limitations include the need for proper technique, risk of globe perforation, and limited volume that can be injected (0.5 to 1.0 mL per site). The Merck Veterinary Manual describes subconjunctival injection as an effective method for delivering antibiotics to the anterior segment of the eye.

Technique for subconjunctival injection:

• Apply topical anesthetic (proparacaine) to the conjunctival surface
• Use a 25-gauge needle on a 1 mL syringe
• Lift the conjunctiva with forceps or a cotton-tipped applicator
• Insert the needle bevel-up into the subconjunctival space
• Inject slowly, observing for bleb formation
• Avoid injecting into the eyelid or sclera

Systemic Administration

Systemic antibiotics are indicated for deep ulcers, perforations, and when concurrent systemic infection is suspected. Advantages include ease of administration and treatment of both eyes simultaneously. Limitations include higher cost, potential for systemic side effects, and lower drug concentrations in ocular tissues compared to topical or subconjunctival routes.

The evidence base for treatment of infectious bovine keratoconjunctivitis published in The Veterinary Clinics of North America Food Animal Practice discusses the role of systemic antibiotics in IBK management. Systemic therapy alone is generally not recommended for superficial ulcers but may be necessary for severe cases.

Record System for Treatment Tracking

A standardized record system allows veterinarians to track individual animal responses, identify treatment failures early, and evaluate herd-level trends. The following record fields should be included for each treated animal.

Individual Treatment Record

Record the following information for each eye treated:

• Animal identification (ear tag number, breed, age)
• Date of initial examination
• Ulcer grade (1 through 4)
• Fluorescein stain result (positive or negative, size in mm)
• Corneal edema severity (mild, moderate, severe)
• Presence of vascularization or melting
• Medications administered (drug, dose, route, frequency)
• Surgical procedures performed
• Re-examination dates and findings
• Outcome (healed, improved, unchanged, worsened, enucleated)

The World Organisation for Animal Health emphasizes record-keeping as essential for animal health surveillance and disease control in livestock populations.

Herd-Level Treatment Log

Maintain a herd-level log that includes:

• Total number of animals examined
• Number of eyes affected
• Ulcer grade distribution
• Treatment protocols used
• Number of animals requiring re-treatment
• Number of animals requiring surgery
• Treatment success rate (percentage healed within 7 days)
• Average time to healing

This data helps identify patterns such as increasing severity over time, clustering of cases in specific age groups, or declining treatment efficacy that may indicate antibiotic resistance.

Troubleshooting Non-Responsive Cases

When a corneal ulcer or IBK case does not respond to initial therapy within 48 to 72 hours, a systematic troubleshooting approach is needed. The following steps help identify the cause of treatment failure.

Step 1: Confirm the Diagnosis

Re-examine the eye with fluorescein stain to confirm that the ulcer is still present. A negative stain indicates epithelial healing, and continued medical therapy may not be needed. A positive stain with an enlarged or deepened ulcer indicates progression despite treatment.

Consider alternative diagnoses if the clinical presentation is atypical. Other causes of corneal disease in cattle include:

• Foreign body (plant material, dirt, feed)
• Entropion (inverted eyelid)
• Trichiasis (aberrant eyelashes)
• Chemical irritation (ammonia from urine, disinfectants)
• Viral keratitis (infectious bovine rhinotracheitis)

The Merck Veterinary Manual lists differential diagnoses for corneal ulcers in large animals.

Step 2: Assess Treatment Compliance

Determine whether the prescribed treatment was administered correctly and at the appropriate frequency. Common compliance failures include:

• Missed doses due to animal handling difficulties
• Incorrect drug concentration or volume
• Expired or contaminated medications
• Improper storage of medications (heat, light exposure)

If compliance is poor, consider switching to subconjunctival antibiotics or a longer-acting formulation. The Merck Veterinary Manual notes that treatment failure in ocular infections is often due to inadequate drug delivery instead of antibiotic resistance.

Step 3: Evaluate for Secondary Infection

Corneal ulcers can become infected with secondary bacterial or fungal pathogens. Signs of secondary infection include:

• Yellow or green ocular discharge
• Corneal melting (keratomalacia)
• Hypopyon (pus in the anterior chamber)
• Rapid progression of ulcer depth

Collect samples for aerobic culture and sensitivity testing. Include fungal culture if the ulcer has a white or fluffy appearance. The evidence base for treatment of infectious bovine keratoconjunctivitis published in The Veterinary Clinics of North America Food Animal Practice discusses the role of secondary pathogens in IBK complications.

Step 4: Consider Antibiotic Resistance

Antibiotic resistance in Moraxella bovis has been documented in multiple studies. A study on antimicrobial susceptibility of Moraxella bovis published in Veterinary Microbiology found varying resistance patterns among isolates. Another study on antibiotic sensitivity of an Argentine strain collection of Moraxella bovis published in Veterinary Therapeutics Research in Applied Veterinary Medicine also documented resistance to commonly used antibiotics. A more recent study on drift of antimicrobial resistance of bacterial pathogens of the Moraxella group published in Bio Web of Conferences indicates ongoing changes in susceptibility patterns.

If resistance is suspected, change the antibiotic based on culture and sensitivity results. Consider using a different drug class or combination therapy. The American College of Veterinary Internal Medicine provides resources on antimicrobial stewardship in veterinary practice.

Step 5: Re-evaluate Environmental Factors

Environmental factors can delay healing or cause reinfection. Assess the following:

• Fly population and control measures
• Dust levels in the housing area
• Sunlight exposure (ultraviolet light)
• Ventilation and ammonia levels
• Stocking density and pen cleanliness

If environmental factors are contributing to treatment failure, implement corrective measures before continuing therapy. The World Organisation for Animal Health emphasizes environmental management as a component of disease control programs for livestock.

Comparison of Surgical Options for Deep Ulcers

When medical therapy fails or the ulcer is too deep for medical management alone, surgical intervention is required. The choice between third eyelid flap, conjunctival graft, and tarsorrhaphy depends on ulcer depth, location, and available surgical expertise.

Third Eyelid Flap

The third eyelid flap provides mechanical protection for the cornea and is the most commonly performed surgical procedure for corneal ulcers in cattle. Advantages include technical simplicity, low cost, and the ability to perform under sedation and local anesthesia. The flap covers the entire cornea, reducing exposure to dust, flies, and sunlight.

Limitations include inability to visualize the cornea during healing, potential for flap displacement, and the need for suture removal after 10 to 14 days. The Merck Veterinary Manual describes the third eyelid flap as a surgical option for corneal protection in cattle.

Indications for third eyelid flap:

• Deep stromal ulcers that are not perforated
• Descemetocele with intact Descemet's membrane
• Postoperative protection after corneal surgery
• Animals in dusty or high-fly environments

Conjunctival Graft

A conjunctival graft provides vascular support and structural integrity for deep corneal ulcers. This procedure is indicated when the ulcer is at risk of perforation or has already perforated. Advantages include direct blood supply to the ulcer site, which promotes healing and provides antibiotic delivery.

Limitations include the need for advanced surgical skills, general anesthesia, and specialized instruments. The graft may also cause corneal scarring and vision impairment. The Merck Veterinary Manual lists conjunctival grafts as a surgical option for deep corneal ulcers in large animals.

Indications for conjunctival graft:

• Corneal perforation
• Descemetocele with impending perforation
• Deep stromal ulcer with melting
• Failed third eyelid flap

Tarsorrhaphy

Temporary tarsorrhaphy reduces corneal exposure and promotes healing by keeping the eyelids closed. This procedure is less commonly used than third eyelid flap but may be appropriate for superficial ulcers in animals with exposure keratitis.

Advantages include technical simplicity and the ability to inspect the cornea by opening the sutures. Limitations include the need for suture removal and potential for eyelid margin damage. The Merck Veterinary Manual describes tarsorrhaphy as a technique for corneal protection in animals with exposure keratitis.

Indications for tarsorrhaphy:

• Superficial ulcers in animals with facial nerve paralysis
• Exposure keratitis from exophthalmos
• Temporary protection while awaiting specialist referral

Practical Implementation Steps for Outbreak Control

When an IBK outbreak occurs, a structured response plan helps contain the disease and reduce economic losses. The following steps provide a framework for outbreak management.

Step 1: Confirm the Diagnosis

Examine all animals in the affected group. Record the number of animals with clinical signs, ulcer grades, and any complications. Collect samples from representative cases for culture and sensitivity testing if antibiotic resistance is suspected.

Step 2: Isolate Affected Animals

Move affected animals to a separate pen or pasture. Use dedicated equipment for handling and treating these animals. Disinfect handling facilities between groups. The World Organisation for Animal Health provides guidelines for isolation and quarantine procedures in livestock disease control.

Step 3: Implement Treatment Protocols

Treat all affected animals according to the ulcer grade algorithm. Consider mass treatment with subconjunctival antibiotics if more than 10% of the group is affected. Record all treatments in the herd treatment log.

Step 4: Initiate Fly Control

Implement an integrated fly control program immediately. Options include:

• Insecticide ear tags (pyrethroid or organophosphate)
• Pour-on insecticides
• Back rubbers or dust bags
• Environmental management (manure removal, drainage)
• Biological control (parasitic wasps)

The Merck Veterinary Manual emphasizes fly control as a critical component of IBK prevention programs.

Step 5: Review Vaccination Status

If the herd has not been vaccinated against Moraxella bovis, consult with a veterinary immunologist or epidemiologist about vaccination options. Vaccination may reduce the severity and duration of outbreaks but is not a substitute for other control measures. A review of infectious bovine keratoconjunctivitis published in the Journal of Veterinary Internal Medicine discusses vaccination strategies for IBK control.

Step 6: Monitor and Adjust

Monitor the outbreak daily for the first week. Record new cases, treatment responses, and any complications. Adjust treatment protocols based on culture and sensitivity results. Continue monitoring until no new cases have appeared for 14 days.

Common Failure Patterns in Outbreak Control

Recognizing common failure patterns helps veterinarians adjust control measures before the outbreak worsens.

Pattern 1: Incomplete Isolation

Failure to isolate all affected animals allows continued transmission. Ensure that isolation pens are located away from the main herd and that water sources are not shared. The World Organisation for Animal Health provides guidelines for isolation procedures in livestock disease control.

Pattern 2: Delayed Fly Control

Fly control must be implemented at the first sign of an outbreak. Waiting until the outbreak is established allows flies to spread the bacteria throughout the herd. The Merck Veterinary Manual identifies fly control as a key factor in IBK prevention and outbreak management.

Pattern 3: Inadequate Treatment Duration

Shortening the treatment duration because animals appear improved can lead to relapse. Complete the full course of antibiotics as prescribed. The Merck Veterinary Manual notes that incomplete therapy contributes to treatment failure in ocular infections.

Pattern 4: Ignoring Environmental Factors

Dust, sunlight, and ammonia exposure can delay healing and increase susceptibility. Address environmental factors before or concurrently with medical treatment. The World Organisation for Animal Health emphasizes environmental management as a component of disease control programs for livestock.

Professional Escalation Criteria for Complex Cases

Some cases require referral to a veterinary ophthalmologist or specialist in large animal surgery. The following criteria indicate when escalation is appropriate.

Urgent Escalation

Refer immediately if any of the following are present:

• Corneal perforation with iris prolapse
• Descemetocele with impending perforation
• Hypopyon or endophthalmitis
• Glaucoma secondary to uveitis
• Suspected intraocular foreign body

The Merck Veterinary Manual identifies these conditions as requiring specialist referral for optimal outcomes.

Routine Escalation

Consider referral for:

• Recurrent ulcers in the same eye
• Bilateral deep ulcers not responding to therapy
• Atypical clinical presentation (unusual appearance, slow healing)
• Diagnostic uncertainty (negative fluorescein stain with corneal opacity)
• Need for advanced imaging (ultrasound, CT)

The American College of Veterinary Internal Medicine provides resources for identifying cases that benefit from specialist consultation.

Frequently Asked Questions

What is the most common cause of infectious bovine keratoconjunctivitis?

Moraxella bovis is the primary bacterial pathogen associated with IBK. Other Moraxella species and secondary bacterial invaders may also be involved. The disease is multifactorial, with environmental factors such as ultraviolet light, dust, and flies contributing to the development of clinical signs. A review of infectious bovine keratoconjunctivitis published in the Journal of Veterinary Internal Medicine describes the etiology and pathogenesis of IBK.

How is a corneal ulcer diagnosed in cattle?

Diagnosis is based on clinical examination and fluorescein staining. A positive fluorescein stain indicates loss of corneal epithelium. The size, depth, and location of the ulcer should be documented. Corneal cytology and culture may be indicated in refractory cases. The Merck Veterinary Manual describes diagnostic procedures for corneal ulcers in large animals.

What antibiotics are effective for treating IBK?

Various antibiotics have been evaluated for treatment of IBK. The choice of antibiotic should be based on expected susceptibility patterns and local resistance data. Culture and sensitivity testing is recommended when initial treatment fails. A systematic review and meta-analysis of antibiotic treatment for infectious bovine keratoconjunctivitis provides an update on evidence for different antibiotic classes. The evidence base for treatment of infectious bovine keratoconjunctivitis continues to evolve.

When is surgical treatment indicated for corneal ulcers?

Surgical treatment is indicated for deep ulcers, descemetoceles, corneal perforation, and ulcers that do not respond to medical therapy. Third eyelid flap, conjunctival graft, and tarsorrhaphy are common surgical options. Enucleation is reserved for non-functional, painful eyes. The Merck Veterinary Manual provides indications for surgical intervention in corneal ulcer management.

How can IBK outbreaks be controlled?

Outbreak control involves isolation of affected animals, fly control, vaccination, and biosecurity measures. An integrated approach is most effective. Monitor the herd for new cases and adjust control measures as needed. The World Organisation for Animal Health provides frameworks for outbreak management in livestock populations.

What is the role of fly control in preventing IBK?

Flies are mechanical vectors for Moraxella bovis. Effective fly control reduces the transmission of the bacteria between animals. Use an integrated approach including insecticides, environmental management, and biological control agents. The Merck Veterinary Manual emphasizes fly control as a critical component of IBK prevention.

Is vaccination effective for preventing IBK?

Vaccination against Moraxella bovis may reduce the incidence and severity of IBK. Consult with a veterinary immunologist or epidemiologist for specific vaccine recommendations. Vaccination should be part of a comprehensive control program. A review of infectious bovine keratoconjunctivitis published in the Journal of Veterinary Internal Medicine discusses the role of vaccination in IBK prevention.

What are the signs of antibiotic resistance in IBK treatment?

Signs of antibiotic resistance include failure to respond to treatment within 48 hours, progression of clinical signs despite therapy, and recurrence of disease after treatment. Culture and sensitivity testing is recommended in these cases. Published studies have documented antimicrobial resistance in Moraxella bovis isolates. Studies on antimicrobial susceptibility of Moraxella bovis and drift of antimicrobial resistance of bacterial pathogens of the Moraxella group indicate ongoing changes in susceptibility patterns.

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References and Further Reading

• www.acvim.org
• Merck Veterinary Manual. Merck Veterinary Manual.
• Animal Health and Welfare. World Organisation for Animal Health.
• Evidence Base for Treatment of Infectious Bovine Keratoconjunctivitis.. The Veterinary clinics of North America. Food animal practice, 2021.
• Infectious bovine keratoconjunctivitis (pinkeye).. The Veterinary clinics of North America. Food animal practice, 2015.
• A systematic review and meta-analysis of the antibiotic treatment for infectious bovine keratoconjunctivitis: an update.. Animal health research reviews, 2016.
• Antibiotic treatment of infectious bovine keratoconjunctivitis.. The Cornell veterinarian, 1990.
• Infectious bovine keratoconjunctivitis: a review.. Journal of veterinary internal medicine, 1998.
• Future Directions for Research in Infectious Bovine Keratoconjunctivitis.. The Veterinary clinics of North America. Food animal practice, 2021.
• Isolation identification of Moraxella bovis from cattle and its antibiotics susceptibility. Indian Veterinary Journal, 2003.
• Serotypes and antibiotic sensitivity of Moraxella bovis isolated from an outbreak of infectious bovine keratoconjunctivitis. Canadian Journal of Comparative Medicine, 1984.
• Antimicrobial susceptibility of Moraxella bovis. Veterinary Microbiology, 1998.
• Antibiotic sensitivity of an Argentine strain collection of Moraxella bovis.. Veterinary Therapeutics Research in Applied Veterinary Medicine, 2000.
• Diversity of Moraxella spp. strains recovered from infectious bovine keratoconjunctivitis cases in Uruguay. Journal of Infection in Developing Countries, 2013.
• Drift of antimicrobial resistance of bacterial pathogens of the Moraxella group. Bio Web of Conferences, 2024.

This article is educational and is not a substitute for veterinary diagnosis or treatment. Contact a veterinarian for advice about an individual animal.