Cow Ear Discharge: Causes, Infection Signs & What to Do
- Ear discharge in cows is not normal and may be caused by otitis externa, middle ear infection, mites, trauma, or a foreign body.
- Yellow, green, bloody, or foul-smelling discharge is more concerning than a small amount of dry wax.
- Head tilt, stumbling, drooping ear, facial asymmetry, fever, or pain can mean deeper ear disease and need urgent veterinary care.
- Your vet may use an otoscope, collect a sample for cytology or culture, and choose topical or systemic treatment based on the exam.
- Do not put ear drops, oils, peroxide, or homemade rinses into the ear unless your vet has checked the eardrum.
Common Causes of Cow Ear Discharge
Ear discharge in a cow usually means inflammation somewhere in the ear canal or deeper ear structures. In cattle, this may start as otitis externa in the outer ear canal, or it may involve the middle ear as otitis media. Merck notes that middle ear disease occurs in large animals, including ruminants, and cattle cases can involve organisms such as Mycoplasma bovis, Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni. When infection is present, discharge may look waxy, pus-like, bloody, or have a bad odor. (merckvetmanual.com)
Other possible causes include trauma, a foreign body such as plant material, irritation from rough cleaning, and less commonly parasites or mites affecting the ear region. Merck also notes that overcleaning and treatment-related trauma can contribute to otitis externa, which matters because well-meant home care can sometimes worsen inflammation. In chronic cases, the ear canal can become swollen, narrowed, and harder to examine. (merckvetmanual.com)
A deeper infection is more serious. If infection extends into the middle or inner ear, cows may show head shaking, pain, reduced hearing, head tilt, or balance changes. Untreated middle ear disease can progress and may lead to rupture of the eardrum with drainage from the ear. That is one reason any persistent discharge deserves a veterinary exam rather than watchful waiting alone. (merckvetmanual.com)
When to See the Vet vs. Monitor at Home
See your vet the same day if your cow has ear discharge plus any of these signs: fever, marked swelling, strong odor, obvious pain, head tilt, circling, stumbling, eye flicking, facial droop, trouble chewing, reduced appetite, or depression. Merck describes head tilt, nystagmus, and other vestibular signs with inner ear involvement, and these signs raise concern for deeper disease that should not be managed at home. (merckvetmanual.com)
A prompt but not necessarily emergency visit is still wise if the discharge is new but your cow is otherwise bright, eating, and walking normally. Yellow, tan, black, or bloody material, repeated head shaking, scratching, or ear sensitivity all support getting the ear checked soon. Ear disease is often painful, and your vet may need to confirm whether the eardrum is intact before any medication is used. (petmd.com)
Home monitoring is only reasonable for a very short window if you are seeing a tiny amount of dry debris without odor, swelling, pain, or behavior change. Even then, avoid putting anything into the ear canal. If discharge continues beyond 24 hours, increases, or your cow develops any neurologic or systemic signs, move from monitoring to veterinary care right away. (merckvetmanual.com)
What Your Vet Will Do
Your vet will start with a physical exam and a close look at the ear canal. That usually includes checking for odor, swelling, pain, debris, wounds, and whether one or both ears are affected. An otoscopic exam helps your vet look deeper into the canal and assess the eardrum when possible. If the ear is very painful or packed with debris, sedation may be needed for a safe and complete exam. (petmd.com)
Your vet may collect a sample of the discharge for cytology and sometimes culture. Cytology can help identify bacteria, yeast, inflammatory cells, or parasites, while culture is more useful in recurrent, severe, or treatment-resistant infections. Merck emphasizes directed antimicrobial therapy and workup for the underlying cause, because ear disease often returns if the trigger is missed. (merckvetmanual.com)
If your vet suspects middle or inner ear disease, they may recommend additional diagnostics such as imaging or a more advanced exam. Merck notes that diagnosis of otitis media and interna is supported by clinical suspicion and imaging such as CT or MRI in some cases. Treatment may include careful cleaning, topical medication if the eardrum is intact, systemic medication when deeper infection is suspected, anti-inflammatory treatment, and follow-up rechecks to make sure the canal is improving. (merckvetmanual.com)
Treatment Options
Spectrum of Care means you have options. Here are treatment tiers at different price points.
Budget-Conscious Care
- Farm-call or clinic exam
- Basic ear exam and visual inspection
- Limited ear cleaning performed by your vet if safe
- Empiric first-line medication when exam findings are straightforward
- Short recheck plan if signs do not improve
Recommended Standard Treatment
- Complete veterinary exam
- Otoscopic ear evaluation
- Cytology or microscopic review of ear debris
- Targeted topical and/or systemic medication based on exam findings
- Pain and inflammation management when appropriate
- Scheduled recheck to confirm improvement
Advanced / Critical Care
- Sedated ear exam and deeper cleaning
- Culture and susceptibility testing
- Advanced imaging or referral-level workup when middle or inner ear disease is suspected
- Systemic treatment for deeper infection
- Close follow-up for neurologic signs, chronic disease, or poor response
Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.
Questions to Ask Your Vet About Cow Ear Discharge
Bring these questions to your vet appointment to get the most out of your visit.
- Does this look like outer ear disease, middle ear disease, or something else?
- Is the eardrum intact, and is it safe to use any ear medication?
- Do you recommend cytology or culture for this discharge?
- Are there signs of mites, a foreign body, trauma, or a respiratory-related infection source?
- Does my cow need topical treatment, systemic treatment, or both?
- What warning signs would mean this is becoming urgent, such as head tilt or balance changes?
- What is the expected cost range for the plan you recommend today?
- When should we recheck the ear if the discharge is not fully gone?
Home Care & Comfort Measures
Until your cow is seen, keep the animal in a clean, dry area and watch closely for appetite changes, fever, head tilt, or worsening pain. If discharge is present, you can gently wipe only the outer ear flap with clean gauze if material is visible on the surface. Do not probe into the ear canal with cotton swabs, fingers, peroxide, oils, or homemade rinses. Ear canals are delicate, and Merck notes that treatment-related trauma and overcleaning can worsen otitis. (merckvetmanual.com)
If your vet has already prescribed medication, use it exactly as directed and finish the course unless your vet tells you to stop. This matters because the wrong product can be unsafe if the eardrum is damaged. PetMD also notes that some ear medications should not be used when the eardrum is ruptured, which is why diagnosis comes before home treatment. (petmd.com)
Good supportive care also means reducing reinjury. Limit rough handling around the head, separate from herd mates if bullying is causing trauma, and keep bedding and fly pressure under control as much as possible. If discharge increases, develops a foul odor, or your cow starts shaking the head more, scratching, going off feed, or acting off balance, contact your vet sooner rather than later. (petmd.com)