Western Stockmen’s of Caldwell, Idaho, a business unit of J.R. Simplot Company, is recalling all Pride Mature Horse feed with the lot number 7701-050306. The lot might contain monensin sodium (Rumensin), a drug compound approved for use in some livestock species which can be fatal if fed to horses.

Pride Mature Horse feed was distributed by the Western Stockmen’s (WSI) store to customers in Caldwell and to Cowpoke Ranch Supply in Corvallis, Mont., and 3 Rivers in Lostine, Ore.

Consumers can identify the product by the WSI Pride Feed bag label on 50-pound bags, which will have a feed tag on the top left of the bag labeled Pride Mature Horse, with the lot number 7701-050306 at the bottom.

The Food and Drug Administration and Western Stockmen’s are conducting an investigation to determine how Rumensin appeared in some of the feed. At least two horse deaths related to the consumption of this feed are being investigated. Additional illnesses are also being investigated