Cow Squinting or Keeping an Eye Closed: Causes & What to Do

The most common cause is infectious bovine keratoconjunctivitis (IBK), often called pinkeye. Merck Veterinary Manual describes IBK as a painful eye disease marked by squinting, tearing, conjunctivitis, and corneal opacity. In cattle, the key early lesion is often a central corneal ulcer, so a cow that suddenly starts squinting should be treated as having a potentially painful ulcer until your vet says otherwise.

Other common causes include eye trauma from hay stems, foxtails, dust, or other plant material; foreign bodies trapped under the eyelids; and irritation from flies, sunlight, and wind. Cornell extension materials note that cases often rise in spring and summer, when UV light and face flies are at their peak. These factors can irritate the eye and also help spread infection between cattle.

Less common but important causes include conjunctivitis from other infectious agents, eyeworms, uveitis, and more severe injuries such as a deep ulcer or rupture. If the eye looks white, blue, yellow, swollen, or bulging, or if the cow seems unable to see, the problem may be more serious than mild irritation.

Because several conditions can look similar at first, the safest approach is to focus on the signs you can see: pain, tearing, cloudiness, discharge, swelling, and whether the problem is getting worse over hours to a day. Those details help your vet decide whether this is likely pinkeye, trauma, or a deeper eye emergency.

See your vet immediately if your cow is keeping the eye tightly shut, has a cloudy or white cornea, a visible white spot or ulcer, yellow or thick discharge, marked swelling, bleeding, a bulging eye, or signs of reduced vision. Merck lists cloudy eyes and squinting among signs that warrant veterinary attention, and early treatment matters because eye disease in cattle can progress quickly and may lead to scarring or blindness.

You should also call promptly if more than one animal is affected, because pinkeye can spread through a herd. Early treatment can reduce pain and may help limit transmission. If the cow is off feed, losing condition, isolating, or struggling to move because vision is impaired, that adds urgency.

Monitoring at home for a few hours may be reasonable only if the eye was briefly irritated, the cow opens it normally again, there is no cloudiness, no discharge, and no ongoing squinting, and you can safely recheck the eye. Even then, if signs return or persist into the same day, contact your vet.

Avoid a wait-and-see approach when the eye stays closed or looks abnormal. Eye pain in cattle is easy to underestimate, and what starts as tearing and squinting can become a larger ulcer surprisingly fast.

Your vet will start with a history and eye exam, looking for tearing, conjunctivitis, corneal cloudiness, ulcers, foreign material, eyelid injury, and signs that vision is affected. In many cases, they will need safe restraint in a chute or head catch to examine the eye well and protect both the cow and the team.

Depending on what they find, your vet may evert the eyelids to look for a seed head or other foreign body, stain the cornea to check for an ulcer, and assess whether the problem fits pinkeye, trauma, or deeper inflammation. Merck notes that diagnostic sampling from affected eyes can sometimes help identify organisms associated with infectious keratoconjunctivitis, especially in herd problems or unusual cases.

Treatment depends on severity and cause. Common options include systemic antimicrobials, topical or subconjunctival medications, pain control where appropriate, and management changes such as fly control, shade, and separating affected cattle. In more severe cases, your vet may recommend protective procedures such as temporary eyelid closure or referral if the eye is at risk.

Your vet will also talk through herd-level prevention if pinkeye is suspected. That may include reducing dust, controlling face flies, trimming irritating weeds, and reviewing whether vaccination makes sense for your operation, since Merck notes that vaccine benefit can vary by herd.

Home care should support, not replace, veterinary treatment. Move the cow to a clean, shaded area if possible, because bright sunlight often makes eye pain worse. Reduce exposure to dust, tall seed heads, and face flies, and watch the herd for other animals starting to tear or squint.

If your vet has already examined the cow, follow the medication and recheck plan exactly. Give treatments on schedule, use safe restraint, and keep notes on whether the eye is opening more, tearing less, or becoming clearer. If the eye becomes whiter, yellower, more swollen, or stays tightly shut, contact your vet right away.

Do not use human eye drops, leftover ointments, or steroid-containing products unless your vet specifically directs you to. Some eye medications are unsafe when a corneal ulcer is present. Also avoid trying to dig out debris unless your vet has shown you how and it is safe to do so.

Comfort care at home often centers on environment: shade, lower fly pressure, less dust, and easier access to feed and water if vision is reduced. These steps can make a meaningful difference while the eye heals, but they work best alongside prompt veterinary guidance.