The United States is home to 26 species of rattlesnakes, making rattlesnake bites relatively common events in equine medicine. A talk entitled, "Just another Snake Bite? Pathophysiology, Treatment, & Long-Term Effects," was included at the American College of Veterinary Internal Medicine (ACVIM) Forum, held June 4-7.

According to Lyndi Gilliam, DVM, Dipl. ACVIM, assistant professor in the department of Veterinary Clinical Sciences at the Center for Veterinary Health Sciences, Oklahoma State University, "rattlesnake bites can affect horses in a number of ways because the venom contains a mixture of natural products that can cause extensive tissue damage, coagulopathy (clotting abnormalities) and/or thrombocytopenia (low platelet counts) leading to bleeding disorders, cardiovascular toxicity (heart damage), and neurotoxicity (nerve damage)."

Horse owners definitely need to resist the urge to begin sucking the venom from their horse's rattlesnake bite, as this was certainly not one of the recommendations made by Gilliam.

Instead, Gilliam provided a concise description of the appropriate management of rattlesnake bites which includes:

  • Seek veterinary attention;
  • Immobilize the horse as much as possible to minimize the spread of toxins;
  • Don't apply ice or a tourniquet.

A veterinarian would then:

  • Perform blood work (e.g., fibrinogen, red blood cell morphology, clotting times) to assess severity of the bite;
  • Administer of intravenous fluids (if indicated) to improve blood flow to the affected tissues;
  • Utilize pain medications appropriately, and;
  • If financially feasible, use antivenin.

"I also recommend the routine administration of tetanus toxoid (if the horse is not current) and prophylactic antibiotics in cases of envenomation. Corticosteroids are controversial in the scientific literature but have been very beneficial in my patients," said Gilliam.

While death due to rattlesnake bites is rare, long term complications can and do occur. In particular, cardiac dysfunction is not uncommon and follow-up examinations should be performed at least 12 months following the incident.

Gilliam's research at Oklahoma State University funded by the ACVIM Foundation has documented that heart muscle damage does occur in horses bitten by rattlesnakes. Research is ongoing to determine the exact portion of the venom causing the damage and to try to establish optimal treatment/prevention for potential career or life-ending cardiac damage.

About the Author

Stacey Oke, DVM, MSc

Stacey Oke, MSc, DVM, is a practicing veterinarian and freelance medical writer and editor. She is interested in both large and small animals, as well as complementary and alternative medicine. Since 2005, she's worked as a research consultant for nutritional supplement companies, assisted physicians and veterinarians in publishing research articles and textbooks, and written for a number of educational magazines and websites.

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