CLOVIS, Calif. (AP) — The owner of horse training and riding lesson business in Fresno County is seeking a settlement after 13 of her horses died as a result of contaminated cattle feed.

The Fresno Bee reports that 13 horses at Black Fence Farm boarding stables in Clovis died or had to be put down and 36 horses suffered permanent neurological damage in September after eating feed that was contaminated with monensin.

Monensin is a substance that is fed to cattle to increase digestion. It is toxic for horses.

Western Milling of Goshen, the company that made the feed, issued a voluntary recall on Sept. 25 for its Western Blend horse feed.

Black Fence owner Katie Flanigan’s lawyer says he expects to settle with the feed company out of court. He has not yet filed a lawsuit.