According to Kim A. Sprayberry, DVM, Dipl. ACVim of the University of Florida, horses are highly susceptible to botulism toxins. In fact, she dubs botulism as "A Perfect Killer" because of the effects the toxins have on a horse. Vaccination, feed and water management are key to prevention of this deadly disease.
Horse feed as source of botulism
Horse owners feeding processed feed cubes or pellets, should be aware that these feeds may contain botulism spores since carcasses of rodents can contaminate processed feed when incorporated into the ingredients.
Horse owners feeding processed feed cubes or pellets, should be aware that these feeds may contain botulism spores since carcasses of rodents can contaminate processed feed when incorporated into the ingredients.
Botulism is an often-lethal disease caused by a bacterial toxin. Although the disease can affect nearly all warmblooded animals, it is particularly deadly in horses, because they are more sensitive to the effects of the toxin than other animals.
The disease can strike suddenly and result in death in horses that were perfectly healthy the day before. Horses’ best chance at survival lies in being treated with antitoxin as quickly as possible, but the disease often leaves no tangible footprint for veterinarians to detect through testing.
This makes it necessary to recognize the clinical signs that are suggestive of the disease and make the diagnosis on that basis alone.The disease is not caused by the bacterium Clostridium botulinum, but rather by the toxins that it produces.
Botulinum toxin is one of the most potent biotoxins known, which is not surprising given that C. botulinum is a member of a family of lethal pathogens that are all capable of causing rapid, severe sickness and death.
Horses get botulism toxin in three basic ways: ingestion of toxins, ingestion of the bacterium and internal production of toxins from wounds. The toxin might be present as a contaminant in feed, or if there are droppings or carcasses of small rodents in the feed or water.
Sometimes a rodent carcass is incorporated into a bale during baling. Because horses as a species are
fastidious eaters, they will avoid consuming hay that is contaminated by animal remains when possible. But when processed feeds such as cubes or pellets are fed, it is impossible for horses to eat around the contaminant, and consumption of the deadly spores can occur.
The best methods of prevention include making sure that all horse feed is clean, harvested and prepared properly and are not allowed to become contaminated. Horse troughs and feed bins should be cleaned on a regular basis and water should be fresh each day to preclude becoming contaminated by rodents or bird droppings. A vaccine is available but is usually recommended only in endemic areas.
Learn more about Botulism in Horses