Blister Beetles in Alfalfa Hay

Did you know that it is possible that the alfalfa hay you feed to your horses can contain a deadly bug called blister beetles?  Although these deadly little bugs may only cause limited damage to the plants, they can be potentially deadly to our livestock.

What does the Blister Beetle look like?
Blister beetles are usually ½ inch to 1 inch in length and can be black, brown, gray or even orange-striped.  Blister beetles have a narrow body with a distinct neck.  They also have antennae’s that are about 1/3 the length of their entire body.

What makes the Blister Beetle so deadly?
Blister Beetles contain a highly toxic drug called cantharidin.  Cantharidin is comparable to cyanide and strychnine in toxicity.  Cantharidin can cause severe skin inflammation or damage to the stomach lining, small intestine, kidney, urinary tract and urethra.  It could take less than 100 small beetles to kill a horse.  Even hay that has dried juice from crushed beetles can cause symptoms.

What are the symptoms you should look for?
Your horse will show signs of colic, depression, dehydration, sweating, diarrhea, pawing, fever and frequent attempts to urinate.

What should I do if I think my horse had ingested Blister Beetles?
If your horse is showing any of the above signs, you should call Dr. McCallister as soon as possible.  Check the hay that you have been feeding your horse.  A horse that has digested Blister Beetles can die within 72 hours.  Early detection and treatment can improve the prognosis, but there is no “cure” for the toxin.

If you have any questions regarding this or any other issues your pet may be having, Please contact our office at 505-869-2627.