As we head into summer we again begin the season for rattlesnakes and unfortunately venomous rattlesnake bites. As most of us know, there is a large population of rattlesnakes along the Colorado Front Range. As one moves close to the foothills, rattlesnakes become especially abundant. The foothills contain many burrows for hibernation created by one of their large food sources, the young Prairie Dog. The rattlesnake encountered in our area is the Prairie Rattlesnake, a member of the Pit Viper family. Their detection of prey depends upon a very sensitive thermo-receptor unit on their head, between their eyes and nostrils. Most snakes are normally timid and secretive. When approached, these snakes usually remain quiet to avoid detection, and they may try to escape if given an opportunity. When frightened, cornered, or attacked, rattlesnakes will stand their ground and may attempt to strike at or bite their intruder. This is where our horses seem to get into trouble!
Although most horses will avoid snakes and snakes have no interest in our horses, mishaps do occur. A horse is most likely to encounter a rattlesnake while grazing, and thus the majority of snakebites on horses are found on the face or muzzle. These bites are definitely a medical emergency and not easily treated by the horse owner in the field. The most important step in handling a snake bitten horse is remaining calm and seeking veterinary medical assistance. Excitement and shock in a bitten horse will cause the hemo-toxic and cardio-toxic venom of a rattlesnake to spread faster through the circulatory/lymphatic system of the horse's body. You must also work to keep your horse calm and avoid unnecessary movement. Time is critical with any snakebite; you should seek veterinary help as soon as possible. The location of the bite and the amount of venom injected are the main factors affecting the seriousness of the bite. In most cases, the bite area will swell, turn black and blue, and can be very painful. The swelling encountered is typically through the muzzle and nostril area and thus asphyxiation is a major concern. Additional concerns include skin and tissue necrosis (dying) due to toxins and infection, tetanus, and long-term cardiac effects. The effects will be even more severe when dealing with a foal, since there are more toxins per body weight.
Any cutting or suction by the owner, with their mouth or a mechanical instrument in the bite area, IS NOT RECCOMENDED and can be more dangerous than the snakebite itself. Remember that the use of ice, aspirin, alcohol, or most tourniquets for snakebite ARE NOT recommended.
In the vast majority of snakebite cases that we see each year, we are summoned early and the outcome for the horse is excellent. Our goals when treating a snake bitten horse are to aid or reestablish airway function, limit necrosis, decrease swelling, and limit or prevent long-term cardiac effects of the venom. After initial treatment, which may include, establishing opening of the airways, anti-venom, anti-inflammatory drugs, antibiotics, and tetanus protection, the patient will remain on drugs for some time. The degree of toxin travel through the blood stream and severity of tissue necrosis will dictate the follow-up procedures.
Should you find yourself in the position of having a horse that has just encountered snakebite and there is no veterinary help available. Remember the following tips: