Summer is a favorite season for riders, their horses and, unfortunately, snakes.

The most dangerous snake to a horse is the rattlesnake, most commonly found in the southwest and far west United States. Other venomous snakes include copperheads and water moccasins, found in the woods and streams of the central and eastern regions of the country.

Because horse owners seldom witness their horse being bitten, it is critical that they recognize clinical signs of snakebite and take appropriate action. Rattlesnakes, copperheads and water moccasins belong to the pit viper family, and their venom contains toxins and digestive enzymes that cause extreme local swelling, marked tissue damage and direct effects on the heart.

Bite Locations

Horses, especially inquisitive foals, are most frequently bitten on the nose, head or neck. They are less frequently bitten on the legs and chest unless they stumble across a snake in tall grass. Bites to the lower legs are seldom severe, because those areas consist of tendons and bone, rather than muscle.

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Bites to the upper leg, chest or neck are the most critical type of bite. These can be life-threatening because the blood circulating through the muscles rapidly dispenses venom through the body and to the heart.

If the horse is bitten on the nose or head, the result is immediate swelling and pain at the wound site. A blood-stained discharge can drain from the nostrils, and the head can swell, causing the eyelids to swell shut. If the swelling is severe, constriction of the air passages in the nostrils or throat can result in labored breathing and potential suffocation. The effects of the bite might be severe enough to cause generalized depression and muscular weakness.

Few horses die of snakebite. However, extensive swelling of the throat or nose might close off the horse's airways, resulting in death. A massive injection of venom by a large rattlesnake into the horse's muscle can produce rapid absorption and also result in death. If an owner suspects a horse has been bitten by a poisonous snake, immediate action should be taken.


    • Stay calm. If the bite occurs while riding, dismount and keep the horse calm. The quieter the horse, the slower his heart rate and the slower the absorption of toxin.
    • Do not move the horse. Call a veterinarian. If a veterinarian cannot come to the horse, slowly load him in the trailer and transport him to the clinic.
    • Do not lance the wound in an attempt to suck out the venom. This only puts you at risk of absorbing venom.
    • If the horse was bitten on the nose, watch for signs of swelling or labored breathing. It might be necessary to place a 6- to 8-inch piece of garden hose in each nostril to allow the horse to breathe. Lubricate the hose with a small amount of petroleum jelly and tape the hose in place so it cannot be inhaled.
    • If the bite is on the horse's leg, a tourniquet can be placed above the bite area. Releasing the tourniquet for a few minutes every 15 to 20 minutes will prevent tissue damage.
    • Cold water packs applied to the bite area will delay swelling, but ice or frozen material should not be applied directly to the skin because they might cause additional tissue damage.

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Veterinarian Treatment

    • For severe swelling, a tracheotomy can prevent suffocation. Anti-inflammatory drugs and corticosteroids will reduce tissue swelling.
    • Antivenin can be used at the discretion of the veterinarian to counter the effects of the venom.