Rattlesnake season is again upon us in the state of Texas.  The warm spring weather has awakened the slumbering reptiles from there winter hibernation.  We’ve already seen several dogs and cats at our vet clinic arrive with swollen heads or limbs.  You can’t help but feel sorry for them as they suffer through the symptoms of their encounters with these highly venomous creatures.  Rattlesnake bites in horses are very dangerous and a pretty common occurrence.  Knowing what to do if your horse is unfortunate enough to have a run-in with a rattlesnake can make a huge difference in the recovery time and the extent of the tissue damage caused by the rattlesnake venom. 

Most Common Bite Locations On The Horse and Associated Complications

Horses bitten on the nose do fairly well as long as their airways do not become compromised.  Their heads can swell quite dramatically and the nasal passages can close off.  If this happens, tubes will need to be placed in the nostrils to allow the horse to breath.  Horses with bites to the head can also have problems with food intake due to the pain and swelling associated with the rattlesnake bite and may need alternative means of getting nutrients. 

The next most likely place for your horse to get bitten is on the legs.  As with humans, horses can walk by completely unaware of snakes hidden in the tall grass, brush piles or under rocks and logs and will get within striking distance without even knowing until it is too late.  These types of bites can be the worst, as the swelling in the limb can cut off blood supply to the hoof.  In effect, the horse develops laminitis.  In severe cases life threatening complications can occur, particularly if the rattlesnake’s fangs puncture a joint, usually just above the hairline and hoof wall junction. 

What Should You Do If Your Horse Is Bitten By A Rattlesnake?

Despite all the old western movies depicting snakebite victims having the poison sucked out of their wounds, this is not the recommended first response treatment!  Do not attempt to open the puncture wounds or suck the venom from your horse.  You risk your own health and further contaminating the wound site by doing that. 

If your horse is bitten by a rattlesnake, contact your veterinarian as soon as possible.  Keep the horse calm and confine its movements as much as possible, as increased heart rate and respiration can help spread the venom through the tissues even faster.  If you have a good relationship with your veterinarian, they can help you put together some first aide supplies to keep on hand that will help buy you some time in case you can’t get to the vet quickly.  Giving an anti-inflammatory drug like Banamine or bute can help with the pain and swelling.  Most horse owners have one or both of these drugs available either in the barn, or if traveling, in the tack room of their trailer. 

Most treatment plans will include a course of antibiotics, as risk of secondary infection is high with rattlesnake bites.  The antibiotic of choice is usually penicillin.  However, penicillin is notoriously under dosed by horse owners that take it upon themselves to treat their horses without consultation with their veterinarian.  The correct dose for an average 1000-pound horse is 30 cc intramuscular twice daily.  When administering penicillin injections to your horse, you will want to make sure and rotate the injection site each time to minimize the soreness, alternating between the large gluteal muscles of the rump and the trapezius muscles of the neck.  Do not attempt to give the injections yourself unless you are confident that your horse can handle them.  Some owners have found out the hard way with a well-placed kick that their horses were not tolerant of the painful injections.  Depending on the severity of the bite, your veterinarian may also want to administer a corticosteroid and/or intravenous fluids. 

Within a short time of being bitten, swelling will start to appear around the bite area as the venom invades the surrounding tissues.  Rattlesnake venom works by breaking down the tissues, in effect digesting the tissues.  Excess fluids from this breakdown process will quickly begin draining from the bite area.  Sometimes they find their way out in the general vicinity of the bite wound, but will generally rely on gravity to find the best exit from the body.  You can expect in most cases for these symptoms to begin to subside within the week.  Within a few days of the cessation of drainage, the skin will usually start sloughing from around the area of the bite.  Due to the risk of secondary infection, it is important to keep the area clean, keeping in mind that the area will be extremely painful to the touch.  Warm, soapy water or a mild antiseptic solution should be sufficient to wash the area. 

Last fall was the first time I had to deal with a rattlesnake bite on one of my horses first hand.  He was bitten right on the end of the nose, below the nostril.  The fang marks were approximately 1 inch apart, so it was a fairly large rattlesnake.  We were lucky in that the bite was a “dry bite” in which the snake did not envenomate.  This happens in approximately 50 percent of rattlesnake bite cases.  The snake either has exhausted its supply of venom on a recent meal or is startled and just bites in warning without envenomating.  My horse did have some minor swelling for several days and sloughing of the skin about 4 or 5 days after the bite.  I had anti-inflammatories and antihistamine in the barn and was able to administer those immediately.  I was thankful that I had those supplies already on hand and did not have to wait to start treatment until I could either get my horse to town or get my vet out to my house.  Most veterinarians are happy to walk you through what you need to do as a first response over the phone if you have the necessary medications and supplies at home. 

As with medical emergency, symptoms and treatments will vary from case to case.  Always consult with your veterinarian before starting any treatment plan.  Do not wait until it is a life-threatening scenario before you call.  The old saying, “the best defense is a good offense” is really quite true.  Talk to your veterinarian now, before the emergency arrives, about what kinds of supplies you should have on hand and arm yourself with knowledge.  You are your horse’s first line of defense in all things.  

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Lisa Carter is a Certified Equine Massage Therapist (CEMT), with multiple certifications from several different equine bodywork schools.  She incorporates her knowledge and experience with Parelli Natural Horsemanship, equine bodywork and as a veterinary technician to provide her clients with the resources they need to make informed decisions for their horses.  She encourages and facilitates network building between equine health care professionals, working together to find the best combination of therapies to meet the needs of the “whole horse”.  

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