Snake Bite Preparedness

Q. Our area has a healthy population of rattlesnakes. We spend six to 10 hours a week on trails where we have seen snakes. I would like to be prepared in the event one of our horses gets bitten. What are the procedures and supplies we should have on hand?


A. When on excursions into areas frequented by pit vipers (also called crotalids, including rattlesnakes), it is prudent to consider some basic precepts concerning bites. Approximately 20-60% of bites are "dry" or defensive type of bites with little or no venom injected by the snake. These are bites that do not swell much within 10 to 15 minutes of being bitten and are not overly painful. It is difficult to ascertain whether a bite is dry, so assume envenomation (injection of venom) and proceed to obtain veterinary care. Rapid swelling and pain suggest venom injection. Venom has a Super Glue-like consistency and is absorbed rapidly from the bite site within 30 seconds to several minutes. Cutting an incision on the bite and suction is not recommended; icing of the bite is not a good idea, nor is a tourniquet.

Most bites occur on the muzzle in curious horses, and application of a dry absorbent wrap is not possible. Things to consider bringing on such excursions would be:

  • Wrap material (dry sheet cottons); 
  • Vetrap, two rolls;
  • Two 12-inch sections of three-quarter-inch or one-inch diagonal gauze;
  • Garden hose or taped 35-cc syringe casings with the ends bored out to insert into nostrils of horses with rapidly increasing muzzle swelling from a facial strike; and
  • Non-steroidal anti-inflammatory medication (prescription from your veterinarian).

If a horse is bitten, time is of the essence and prompt evacuation for veterinary care is recommended even though death is rare in adult horses. Complications days or weeks later are often responsible for adult horse deaths from rattlesnake bites. Asphyxiation from massive throat swelling might necessitate a tracheotomy in rare cases. A non-steroidal anti-inflammatory can minimize swelling and pain. Walking, not running, is recommended to avoid elevation of blood pressure and venom absorption.

Leg and torso bites are especially troublesome, and the bitten limb can be promptly wrapped to compress tissue and minimize swelling and absorption of toxin into general circulation. Antibiotics (likely injectable) should be considered once veterinary care is secured due to the "dirty" nature of snake fangs and infection potential. Maintain a current tetanus vaccination.

In summary, minimize swelling and venom absorption, maintain nostril airflow, and seek veterinary assistance immediately. These steps should allow most horses to recover without antivenin (antitoxin active against venom) administration. Do not incise, ice, or apply a tourniquet to snake bites.

About the Author

Edward D. Voss, DVM, Dipl. ACVIM

Edward D. Voss, DVM, Dipl. ACVIM, is a practitioner based in Gilbert, Ariz.

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