The U.S. Food and Drug Administration is cautioning horse owners not to feed recently recalled Top Of The Rockies brand alfalfa cubes. The cubes are being investigated for suspected botulism contamination linked to illness and death of horses in Colorado, Louisiana, New Mexico and Texas.

The FDA is aware of at least 98 horses in those states exhibiting neurologic signs, and at least 45 of those have died or been euthanized due to declining health. The symptoms reported are consistent with botulism, and further testing is underway to determine the exact cause of illness, according to a statement released Saturday by the FDA. Symptoms of botulism include muscle tremors that rapidly progress through the whole body, weakness, decreased tongue tone, agitation and inability to stand. No human illness have been reported.

The 50-pound white and tan plastic bags affected have date codes of 111222, 111322, 111422, 111522, and 111622. The alfalfa cubes have been recalled by the manufacturer, Manzanola Feeds, of Manzanola, Colorado, which distributes them to feed stores and co-ops in 10 states: Arkansas, Colorado, Illinois, Kansas, Louisiana, Missouri, New Mexico, Oklahoma, Texas and Wisconsin.

Some of the bags have been reported to contain cubes with animal fur and tissues, meaning material from an animal was incorporated into the cubes during harvesting. Some people have reported a foul odor inside the bags.

The FDA recommends checking the date code on any Top Of The Rockies brand alfalfa cubes and throwing out the product. If you’re unsure of the date code, do not feed them to horses or any other animals.

For more information, see the FDA advisory.