Snake Bites in Horses

Having spent thirty years in the combined equine and veterinary fields, I am well aware of the danger of rattlesnakes. Working within the small animal veterinary field for many years, I saw what these reptiles can do. I also saw the benefit of prompt medical attention and antivenin. But when my horse, Pal, introduced his nose to a rattler, I wondered what the correct protocol is for a horse.

From my small animal medicine background, I know that rattlesnake bites are never twice the same. I was forever explaining to clients that just because their last cat came through with no medical attention (!) there was no reason to expect a similar outcome with this bite. The bite can be dry or the snake may inject everything it has. Both scenarios present the same in the veterinary hospital. This makes judging outcomes difficult. What works with one animal may fail on another. Due to this never ever believe that just because a previous animal escaped relatively unscathed from a snake bite the next one will too. Snake bites can be fatal, every one is an emergency.

In Pal's case, my veterinarian recommended antivenin. I know the value of antivenin in dogs and cats. Antivenin is size specific with one full bottle being sufficient for cats and most dogs. I wondered what good one vial could do Pal. But again, even the published information on this is hit or miss, it is just too difficult to make a fair comparison of outcomes with such an inconsistent amount of venom per bite.

I was also concerned because most antivenin is made using horses as the host species. A ready bottle of epinephrine in case of anaphylaxis was a simple solution to that concern.

Still uncertain of what value 12 mls of antivenin (the same I would give a cat) would have on a horse, I elected nevertheless to give it. In snake bites, with so little evidence supporting most protocols, and the outcomes so varied, I felt that every advantage should be pursued.

The biggest risk of snake bite in horses, unlike dogs and cats, is suffocation. Horses are unable to breathe through their mouths, and excessive swelling of the nose after a snake bite can close off the airways. Having a length of hose and some lube on hand in snake country isn't a bad idea, as the hose, inserted into a nostril can keep enough of the airway open to keep the horse alive.

Pal was put on fluids and antibiotics, and he did fine, sporting only a small scar on his nose. I have looked into snake training for horses, but sadly it isn't available. I am hoping that pal has learned his lesson.

Snakes have a powerful venom, and that venom can be wildly different from species to species, as well as the reaction to it by any given animal. Horses are most often bitten on their noses, but a leg bite, with its low profusion (blood flow) can be a problem as well.

Rattlesnake venom does several things:
It causes localized tissue death (necrosis) which can lead to ugly scarring, physical defects, and infection.

It causes excessive bleeding by affecting the clotting cascade leading to excessive bleeding. Most snake bites are surrounded by large bruises.

It causes changes to the heart rhythm.

It hurts! Pain should not be under treated. Snake bites hurt, and though NSAIDS (Non-steroidal anti-inflammatories) can exacerbate bleeding, some effort must be made to address pain.

I have lived in snake country my entire life, and this was my first run in with a horse getting nailed by a rattler, it can happen anytime.