Blister beetles contain a poison (cantharidin) that is extremely toxic to horses. Unfortunately, there is not a specific antidote for cantharidin poisoning. Ingestion of even a few beetles results in severe colic and, many times, in death. The death of horses from blister beetle ingestion has been reported from Floridato Arizonaand as far north as Illinois. The states known to have the biggest problems with blister beetles are Texasand Oklahoma.

To date, blister beetle poisoning is not a problem for hay grown in the TreasureValleyregion of Idaho, one reason hay for the 1996 Summer Olympic Games was purchased from Idahohay growers. I agree with your neighbor, however, that regardless of your location or the incidence of blister beetle poisoning there a quick inspection of the hay you are providing to your horse is always a good idea.

There are many things that can be baled into hay that may not be good for your horses, including small, dead rodents that can potentially cause botulism, and aluminum cans that may cause digestive tissue damage.