No doubt you’re well aware of the importance of an annual tetanus vaccinations for your horse. Tetanus is caused by Clostridium tetani bacteria, which form spores that are commonly found in the soil. When the spores end up in an anaerobic environment—such as the depths of a puncture wound—the bacteria are activated and multiply, producing a potent neurotoxin. Within 10 to 14 days, a horse’s skeletal muscles begin spasming, and he may take on a “sawhorse” stance—stiff straight legs and an arched back—as the disease progresses. Eventually, paralysis of the larynx and diaphragm cause suffocation. Tetanus is a brutal and nearly always fatal disease.
Fortunately, the tetanus vaccine is safe and effective. Horses vaccinated with an initial two-dose series followed by an annual booster shot are well-protected. There may be times, however, when additional protection is a good idea.
For people, the immunity conferred by a tetanus shot lasts up to 10 years, while for horses the protection wanes more quickly. That’s why your veterinarian will likely administer a tetanus booster as a precaution when your horse has a significant wound.
If you are tending to your horse’s wound yourself, you can administer a tetanus booster, too, but you need to make sure to purchase the correct product: A tetanus toxoid is a vaccine, but a tetanus antitoxin is the product given to treat an active case of the disease. Antitoxins carry a much higher risk of side effects, including liver damage. You may find both commercially available, but you’ll want to be sure to purchase the toxoid to protect your horse without risking other areas of his health.
This article was originally published in EQUUS 485, February 2018