Fall is a wonderful time of year in Wisconsin; changing colors, crisp days, frosty nights, completion of the summer’s harvest – maturation of pesky burdocks (burrs). They get everywhere and horses are very adept at finding them whether your turn out area has a lot of burrs (or just a few!), or if they just show up in the hay you are feeding. Horses find burrs and add them to their manes, tails and foretops. Part of the time you spend with your horse in the fall may be spent cleaning burrs out of their hair. This is where problems arise – the little tiny burrs or stickers fly about and get into their eyes and underneath their eyelids in the conjunctiva or cornea. A pricker in the eye – ouch!
Identifying Burdock Keratitis
Horses with this issue typically present with burrs in their hair, or had burrs removed from their hair recently. They have a painful eye evidenced by tearing, swollen lids, reddened conjunctiva (the pink tissue under the lids), partially closed eyelids, and possible cloudiness to the cornea (glistening surface of the eye). Typically they have an area of the cornea that is ulcerated and takes up stain when examined by your veterinarian. This stained area corresponds to an area of the conjunctiva that has the burr – this may be seen with magnification, it may be suspected because of blood vessel growth in that area, or it may have more redness than the rest of the underside of the lid. The horse typically needs to be sedated in order to see and remove the offending burr. He may also need to have a nerve block with a topical anesthetic to prevent blinking of the eyelids. Since burrs are so small, removal of one by itself is difficult if not impossible, so usually the suspected area of tissue is removed to get the burr.
Treatment and Removal of Burrs
Treatment with topical antibiotic ointment of the corneal ulcer without removal of the burr will be unsuccessful. The horse won’t become comfortable and the ulcer cannot heal until the burr is removed. Once it is removed, an uncomplicated ulcer typically heals within a couple weeks. Complications, such as a fungal infection of the ulcer, can occur. Some horses may also be left with a corneal scar or a white spot on the eye. These scars usually pose little problem for the horse unless they are very large or obscure their field of vision.
Prevention of Burdock Keratitis
Obviously, the best way to prevent this condition is to rid your pastures and hay of mature burrs. This can be done by mowing pastures repeatedly before the burrs have a chance to mature so that they can’t reseed your fields. Spraying with pasture safe herbicidal products is also an option, as is manually digging them out. Once your horse has a mane full of them, there are a few safe options for removal. Soaking the hair in baby oil helps them slip out more easily and keeps them stuck to the hair rather than flying about. Another option would be to trim the foretop off to remove the burrs en-block and to prevent the re-accumulation for that season. Braiding the hair may help as well.
So enjoy the beautiful fall weather but keep an EYE out for burdocks! Don’t hesitate to call our office at the first sign of eye pain in your horse. Remember – ophthalmic trauma is one equine emergency you never want to wait on – call your veterinarian!
By Lisa Nesson, DVM