BATON ROUGE, La. (AP) – At least 20 horses in Louisiana have died after ingesting bacteria found in some alfalfa hay cubes from a manufacturer in Colorado, state agriculture officials said.

The Louisiana Department of Agriculture and Forestry began notifying livestock owners and others about potential problems with some bags of “Top Of The Rockies Alfalfa Horse Cubes” in mid-December after horses in Louisiana and three other states began showing neurological symptoms consistent with botulism, state officials said.

The U.S. Food and Drug Administration (LDAF) said at least 98 horses in Louisiana, Texas, Colorado and New Mexico have showed symptoms including muscle tremors, trouble swallowing or eating, difficulty standing or collapse. At least 45 of those animals have died or were euthanized due to declining health after eating the cubes.

The LDAF said it had confirmed with the FDA and the California Animal Health & Food Safety Laboratory that Clostridium botulinum type C was in the alfalfa cubes, which causes equine botulism, The Advertiser reported.

State investigators received information that an unopened bag of the cubes, produced by Manzanola Feeds in Manzanola, Colo., contained animal remains.

“This finding indicated that material from an animal or animals may have been incorporated into the cubes during alfalfa harvesting,” a release from LDAF said. “Clostridium botulinum, the bacterium that causes botulism, is commonly present in decaying animal carcasses.”

Manzanola Feeds has recalled its “Top Of The Rockies Alfalfa Horse Cubes” with the date codes 111222, 111322, 111422, 111522, and 111622. More information on how to dispose of the cubes safely can be found at the FDA’s website.

The LDAF said horse owners should immediately contact a veterinarian if a horse ate the product and is showing signs of a neurological illness.