Snake in the Grass

On a late spring morning in rural San Diego County, Sally let her two horses out in the pasture to graze and enjoy the warm sunny day. Her horses were down by the pond lazily munching the native grasses. About two hours after she had put the horses out she went to check on them and noticed that Blaze was extremely lame. Upon closer inspection she noticed significant swelling of the right front leg just above the fetlock. She also noticed two very small trails of blood on the outside of the leg in the same area as the swelling. Sally new immediately that Blaze had been bitten by a rattlesnake.

Rattlesnakes are commonly found in and around the Southern California region. As summer temperatures rise and we spend more time outdoors, the encounters with snakes become more frequent. Rattlesnakes tend to be fairly non aggressive, and will try to get away if given the chance. Because of their curious nature, our horses are typically bitten on the nose when they are investigating this slithering creature. Bites typically occur when the snakes are either startled, or do not have an escape. The other place we see bites are on the lower leg. This typically happens when a horse surprises a snake by either stepping on it or near it, as was the case for Blaze.

There is typically significant swelling at the bite site and the site is very painful. Horses that get a bite on the nose need to be watched for difficulty breathing due to the fact that horses only breathe through their nose. If this happens you may be able to insert pieces of garden hose about 10 inches long into the nostril before they close up from swelling, and then call your veterinarian. A rattlesnake bite is a true emergency. If a horse gets a bite on the leg, walk or trailer the horse to the nearest veterinarian for evaluation. In our experience horses that get a bite on the nose tend to do better than those that are bit on the leg. This is due to the blood flow, and lymph system in the legs that can quickly carry the venom through the body. Although snake bites are an emergency, most horses do well with prompt medical treatment.

The latest tool for aggressively treating rattlesnake bites is an anti toxin plasma produced from horses that have been inoculated with rattlesnake toxin. The horses’ immune system recognizes this toxin as a foreign protein, and makes antibodies against this foreign protein. Since these antibodies are contained in the blood plasma, we are able to harvest the plasma from the inoculated horses and use it to treat horses that may not have the antibodies or do not have enough antibodies to fight the toxin. Giving the horses this plasma significantly increases healing response time, and may even be the difference between life and death.

Upon realizing that Blaze had a snake bite, Sally called Creekside Veterinary Service. Dr. Moss was on call and was able to quickly evaluate the horse. The fang marks were about 1 inch apart, which indicated that this snake was rather large. Swelling was already involving the cannon bone and was progressing into the horse’s knee. Dr. Moss treated the horse with a combination of steroids, NSAIDS, antibiotics, and diuretics to help stop the body’s reaction to the venom. The swelling was spreading quickly due to the bite being on the leg and there was significant potential for serious side effects, so Dr. Moss administered the rattlesnake plasma to minimize complications. Even with aggressive treatment and bandaging Blaze’s leg swelled all the way up to the elbow and was very painful. Two days later the swelling was still present and the horse continued to be very lame. On day three a sweat wrap was applied to the leg and the swelling had decreased significantly. This continued care by Blaze’s owner and the medical treatment Blaze received helped her make a very rapid recovery. Five days after the initial bite Blaze was back in the pasture running and bucking and playing like she had before.

During the spring and summer month’s rattlesnakes are out and around. This does not mean that you shouldn’t trail ride or let your horses out on pasture, in fact we encourage you to. Just remember to be aware of snakes, and make sure you give them their space. By being aware and knowing your surroundings, you and your animals can enjoy the sunny summer weather.

If you suspect your horse has been bitten by a rattlesnake do not hesitate to call the Creekside emergency line at 760 728-2319