Feedstuffs that test at a pH level below 4.5 are probably acid enough not to be contaminated with the toxin. Botulism at a glance Botulism is caused by a neurotoxin produced by the anaerobic bacterium Clostridium botulinum . The toxin produced by C. botulinum is one of the most potent known to man. Eight toxin types, each produced by a different strain of the bacterium, have been identified. Symptoms of botulism can be confused with conditions such as rabies, equine protozoal myeloencephalitis, or tetanus.
Botulism can strike extremely swiftly.
The severity of symptoms is largely dependent on the amount of toxin the horse has ingested. A horse with less toxin might decline slowly. A vaccine for Type B botulism is given routinely to horses in high-risk areas.