NORCO, Calif. (AP) — Tainted hay is suspected of causing sun sensitivity that is leading to rashes and skin infections in horses across Southern California, state officials said.
Vets and horse owners have reported at least two dozen cases of photosensitization in recent weeks, the Riverside Press-Enterprise reported Tuesday. As many as seven cases are in the Riverside County city of Norco.
Affected horses experience infections called photodermatitis, which can result in hair loss and painful lesions.
The source appears to be tainted alfalfa hay from several distributors, with at least some from the Bishop area in the Eastern Sierra, according to the California Department of Food and Agriculture’s Animal Health and Food Safety Services Division.
Toxicologists have not definitively identified the exact substance, but officials believe it might be naturally occurring, the agency’s Dr. Kent Fowler said.
The lack of water caused by California’s severe drought might have caused the levels of some ingredient in alfalfa hay to increase, officials said. The problem could stem from the hay being fed to horses very soon after it was cut and baled. The effect might lessen over time in hay that is kept awhile, the newspaper reported.
The condition typically is not fatal, unless a secondary condition, such as an infection, gets out of control. A horse owner in the Phelan area reported two old horses died of what she believed was photosensitization in recent months, but an investigation didn’t find that sun sensitivity was involved, Fowler said.
Treatment starts with getting horses under shelter or shade, and sometimes turning them out only at night. They should be kept out of sunlight until they heal. Open sores resulting from severe cases might get bacterial infections, which would then most likely require antibiotics administered by a vet.