Conjunctivitis in Pigs: Pink Eye Symptoms, Causes & Treatment

Quick Answer
  • Conjunctivitis in pigs is inflammation of the tissues lining the eyelids and eye surface. It can affect one eye or both.
  • Common signs include red eyes, swelling, tearing, squinting, rubbing the face, and clear, cloudy, or pus-like discharge.
  • In pigs, infectious causes can include Chlamydia suis, but dust, bedding irritation, ammonia, trauma, and foreign material can also trigger pink eye.
  • See your vet promptly if the eye is closed, the cornea looks cloudy or blue, discharge is thick, or your pig is off feed or acting painful.
  • Typical 2026 US veterinary cost range for an uncomplicated exam and treatment plan is about $120-$350, with advanced testing or herd-level care increasing the total.
Estimated cost: $120–$350

What Is Conjunctivitis in Pigs?

Conjunctivitis, often called pink eye, is inflammation of the conjunctiva. This is the thin membrane that lines the inside of the eyelids and covers part of the eye surface. When it becomes irritated or infected, the eye can look red, swollen, watery, or crusty. Merck Veterinary Manual describes conjunctivitis as inflammation of the conjunctiva, and chlamydial conjunctivitis can involve the eye with or without additional upper respiratory signs. (merckvetmanual.com)

In pigs, conjunctivitis is a symptom pattern rather than one single disease. Some pigs develop it from environmental irritation such as dusty bedding, poor ventilation, or ammonia buildup. Others may have an infectious cause, including Chlamydia suis, which Merck notes is endemic in domestic pigs worldwide and can lead to conjunctivitis. (merckvetmanual.com)

Many mild cases improve once the underlying trigger is identified and your vet guides treatment. Still, eye problems can worsen quickly. A red eye can sometimes hide a corneal ulcer, deeper infection, or trauma, so it is safest to have painful or persistent eye changes checked early.

Symptoms of Conjunctivitis in Pigs

  • Red or bloodshot eye tissues
  • Watery, cloudy, or mucus-like eye discharge
  • Swollen eyelids or puffy tissue around the eye
  • Squinting, blinking more than usual, or holding the eye closed
  • Rubbing the face on fencing, bedding, or with a leg
  • Cloudy, blue, or dull-looking cornea
  • Sneezing or nasal discharge along with eye signs
  • Reduced appetite, lethargy, or obvious discomfort

Mild conjunctivitis may start with redness, tearing, and a small amount of discharge. If your pig is bright, eating, and keeping the eye open, your vet may be able to manage it as an uncomplicated case. But eye pain matters. Squinting, a closed eye, thick discharge, or a cloudy cornea can point to a corneal ulcer, trauma, or a more serious infection.

See your vet immediately if the eye looks blue or white, the pig cannot open the eye, there is bleeding, the eye seems bulging, or your pig is also weak, feverish, or off feed. Those signs go beyond routine pink eye and need prompt medical care.

What Causes Conjunctivitis in Pigs?

Conjunctivitis in pigs can be caused by infection, irritation, or injury. One important infectious cause is Chlamydia suis. Merck Veterinary Manual states that C. suis infections are endemic in domestic pigs worldwide and can cause conjunctivitis, respiratory disease, enteritis, and reproductive problems. Chlamydial eye disease may be acute, chronic, or recurrent. (merckvetmanual.com)

Not every red eye is infectious. Dusty housing, rough bedding, poor air quality, ammonia from urine, feed particles, and foreign material can all irritate the conjunctiva. Trauma from pen mates, fencing, or rubbing can also inflame the eye. In some pigs, conjunctivitis may occur alongside rhinitis or other respiratory signs, which can help your vet narrow the cause. Merck notes that chlamydial conjunctivitis can also include sneezing and nasal discharge. (merckvetmanual.com)

Because several different problems can look similar at home, it is important not to assume the cause based on redness alone. A pig with discharge may have simple irritation, but it could also have a corneal injury or a deeper infection that needs a different treatment plan.

How Is Conjunctivitis in Pigs Diagnosed?

Your vet will usually start with a full history and eye exam. That includes looking at the eyelids, conjunctiva, cornea, and type of discharge, plus asking about bedding, ventilation, ammonia smell, recent transport, herd illness, and whether one pig or multiple pigs are affected. If the eye is very painful, your vet may recommend sedation for a safer and more complete exam.

A key part of diagnosis is ruling out problems that can mimic simple pink eye. Fluorescein stain may be used to check for a corneal ulcer, and your vet may look for foreign material or trauma. Merck notes that specific diagnosis of conjunctival disease can involve conjunctival scrapings, cytology, culture, and PCR testing, especially when chlamydial or mycoplasmal infection is suspected. (merckvetmanual.com)

If several pigs are affected, herd-level diagnostics may be more useful than treating one eye in isolation. Laboratory testing can help identify whether Chlamydia suis is involved, although Merck notes that cell culture is sensitive and specific but not widely practical for routine use. Your vet may choose PCR or other testing based on what is available locally and what will change treatment decisions. (merckvetmanual.com)

Treatment Options for Conjunctivitis in Pigs

Spectrum of Care means you have options. Here are treatment tiers at different price points.

Budget-Conscious Care

$120–$220
Best for: Mild, early cases in a bright, eating pig with redness or discharge but no cloudy cornea, severe swelling, or whole-body illness.
  • Office or farm-call exam focused on the affected eye
  • Basic eye flush and visual exam
  • Environmental correction plan such as dust reduction, softer bedding, and improved ventilation
  • Initial topical medication if your vet feels the cornea is not involved
  • Home monitoring instructions and recheck guidance
Expected outcome: Often good when the trigger is mild irritation and changes are made quickly.
Consider: Lower upfront cost, but limited testing means the exact cause may remain unknown. If the eye worsens or an infectious herd problem is present, more care may still be needed.
Most Common

Recommended Standard Treatment

$220–$450
Best for: Most pigs with persistent conjunctivitis, moderate swelling, squinting, thicker discharge, or cases where infection is reasonably suspected.
  • Complete veterinary eye exam
  • Fluorescein stain to check for corneal ulceration
  • Targeted topical medication and or systemic medication selected by your vet
  • Pain-control plan when appropriate
  • Recheck exam in several days to confirm improvement
  • Basic herd and housing review to reduce recurrence
Expected outcome: Good to fair, depending on cause and how quickly treatment starts.
Consider: More complete than conservative care and more likely to catch corneal injury, but it costs more and may still not identify the exact organism without lab testing.

Advanced / Critical Care

$450–$900
Best for: Severe pain, cloudy cornea, recurrent cases, multiple affected pigs, suspected herd outbreak, or cases not improving with first-line care.
  • Sedated or specialty-level eye exam if the pig is painful or difficult to examine safely
  • Conjunctival cytology, PCR, culture, or herd-level diagnostics
  • Systemic treatment plan for suspected chlamydial or more widespread disease as directed by your vet
  • Treatment for corneal ulceration, trauma, or severe secondary infection
  • Isolation and biosecurity recommendations for multi-pig settings
  • Follow-up testing or referral if the eye is not responding as expected
Expected outcome: Fair to good if the underlying cause is identified and treated early; guarded if there is corneal damage or delayed care.
Consider: Highest cost and more handling, but gives the best chance of identifying the cause and preventing repeat problems in group-housed pigs.

Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.

Questions to Ask Your Vet About Conjunctivitis in Pigs

Bring these questions to your vet appointment to get the most out of your visit.

  1. You can ask your vet whether this looks more like irritation, trauma, a corneal ulcer, or an infectious eye problem.
  2. You can ask your vet if fluorescein stain or other eye testing is needed before starting medication.
  3. You can ask your vet whether my pig needs topical treatment, systemic treatment, pain control, or a combination.
  4. You can ask your vet if bedding, dust, ammonia, or ventilation may be contributing to the eye inflammation.
  5. You can ask your vet whether other pigs should be checked or separated if more than one animal has eye or respiratory signs.
  6. You can ask your vet what warning signs mean the eye is getting worse and how soon a recheck should happen.
  7. You can ask your vet whether lab testing such as PCR, cytology, or culture would change the treatment plan.
  8. You can ask your vet about meat withdrawal times or medication restrictions if this pig is part of a food-animal setting.

How to Prevent Conjunctivitis in Pigs

Prevention starts with the environment. Keep housing clean, dry, and well ventilated. Reduce dust from bedding and feed, remove sharp plant material or debris, and address ammonia buildup quickly. These steps lower irritation to the eyes and also support overall respiratory health.

Good observation matters too. Check pigs regularly for early redness, tearing, squinting, or face rubbing so your vet can assess problems before they become more painful. If several pigs develop eye discharge, treat that as a group-management issue rather than a one-pig problem.

Biosecurity and herd health planning can also help. Because Chlamydia suis is widespread in pigs and may be present without obvious signs, isolating newly affected animals when practical, cleaning shared equipment, and reviewing stocking density and stressors with your vet can reduce spread. Merck notes there are vaccines for chlamydiosis in cats but not for other species, so prevention in pigs relies mainly on management, sanitation, and veterinary-guided herd control. (merckvetmanual.com)

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