Q. I have a 6-year-old Arabian gelding who used to spend up to about 12 hours a day on our fescue pasture. As a 4-year-old, he developed lesions on his three white legs on the cannon bone area that were crusty, raw underneath, very sore, and made him lame. His hind legs swelled terribly. One veterinarian said it was scratches, one said a systemic allergy to fescue grass, and one had no idea. A scraping was taken and sent to the University of Georgia Veterinary School with no definite results.

I have tended the painful areas by peeling the crust, washing with Nolvasan, drying the legs, and keeping them clipped. This is the first year I feel I've had control of this problem, and I think more than anything it's because I took him off the fescue pasture and put him in one that had early wheat planted in it for forage for our cows. Have you ever heard of a systemic allergy to fescue grass? If not, anything that you have addressing my problem would be useful.


A. I have not found any reports of fescue grass causing the kind of skin reaction you have described in your horse. Most fescue poisoning in horses is associated with reproductive problems and lack of milk production in foaling mares. However, the clinical signs you describe on your horse's white-skinned areas of his legs suggest a photosensitivity (light sensitivity), especially if the lesions are present in only the white-skinned areas.

Scratches is also a poorly defined problem that occurs in white-skinned areas of the feet. It is thought to be a contact allergy and having moved the horse to a different pasture without fescue in it suggests that it might be an allergic-type response. A skin biopsy of the affected area would shed more light on the likely cause.

About the Author

Anthony Knight, BVSc, MS, Dipl. ACVIM

Anthony P. Knight, BVSc, MS, Dipl. ACVIM, is a professor of large animal medicine in the College of Veterinary Medicine and Biomedical Sciences at Colorado State University. He received his veterinary degree from the University of Nairobi, Kenya, in 1968. After completing a master’s degree at Colorado State University, he joined the faculty in 1974. His current professional interests include livestock heath, foreign animal diseases, emergency management, and plant toxicology. He has written two books on poisonous plants of animals in North America, and maintains a poisonous plants website for use by anyone wanting poisonous plant information.

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