Tetanus in Horses: Lockjaw Signs, Wound Risk, and Prevention
- See your vet immediately if your horse has stiffness, a sawhorse stance, trouble chewing, a raised tail, muscle spasms, or sensitivity to sound and light.
- Tetanus is caused by a toxin from *Clostridium tetani* entering through a wound, surgical site, foot puncture, umbilicus in foals, or reproductive tract injury after foaling.
- Even a small or hard-to-find wound can lead to tetanus. The wound severity does not reliably predict risk.
- Diagnosis is usually based on recent wound history plus classic neurologic and muscle signs. Treatment often starts before lab confirmation.
- Prevention matters most: tetanus toxoid is a core equine vaccine, with annual boosters and an extra booster after certain wounds or surgeries if the last vaccine was 6 months or more ago.
What Is Tetanus in Horses?
See your vet immediately if you think your horse may have tetanus. This is a life-threatening neurologic disease caused by a toxin made by the bacterium Clostridium tetani. Horses are one of the species most sensitive to this toxin, which is why prevention is such a big part of routine equine care.
The bacteria themselves usually stay in a wound where oxygen is low. From there, they produce a toxin that travels through nerves and interferes with normal muscle relaxation. Instead of moving smoothly, the horse develops increasing stiffness, spasms, and the classic "lockjaw" appearance. As the disease progresses, breathing, swallowing, and standing can become difficult.
Tetanus is not contagious from horse to horse. It comes from environmental exposure, especially soil and manure contamination of wounds. Because spores can survive in the environment for years, any horse can be exposed, including horses kept in clean-looking barns and paddocks.
Vaccination has made tetanus far less common in well-protected horses, but cases still happen, especially in horses with incomplete vaccine history or after wounds that seemed minor at first. Early recognition and fast veterinary care can improve the outlook.
Symptoms of Tetanus in Horses
- Early stiffness or a short, choppy gait, often starting subtly
- Sawhorse stance with rigid legs and difficulty turning or backing
- Lockjaw or trouble opening the mouth to chew and swallow
- Prolapse of the third eyelid, especially when startled
- Raised tail and a tense facial expression
- Muscle tremors or painful spasms triggered by touch, sound, or light
- Hypersensitivity and exaggerated startle responses
- Reduced manure or urine output because movement and posture become difficult
- Trouble eating, drinking, or swallowing safely
- Difficulty rising, recumbency, breathing problems, or sudden death in severe cases
Tetanus often starts with vague stiffness, then progresses to obvious rigidity and spasms over hours to days. Many horses become extremely reactive to normal barn noise, bright light, or handling. A recent wound may be present, but sometimes the wound is tiny, healed over, or never found.
When to worry: immediately. If your horse has lockjaw, a stiff "sawhorse" posture, repeated spasms, trouble swallowing, or breathing changes, this is an emergency. Prompt veterinary care gives your horse the best chance and can also help your vet address pain, hydration, nursing support, and wound management early.
What Causes Tetanus in Horses?
Tetanus develops when Clostridium tetani spores enter the body through damaged tissue and find the low-oxygen conditions they need to grow. These spores are common in soil, dust, and manure, so exposure is part of normal horse life. The problem is not the dirt alone. It is the combination of contamination plus a wound or damaged tissue where the bacteria can multiply.
Common entry points include puncture wounds in the foot, lacerations, surgical incisions, castration sites, the umbilicus in foals, and trauma to the reproductive tract after foaling. One important point for pet parents to know is that wound size does not predict danger. A very small puncture can be more risky than a large, easy-to-clean cut.
Horses with incomplete vaccination, unknown vaccine history, or overdue boosters are at the highest risk for severe disease. Vaccinated horses can still need a booster after certain injuries or surgeries, depending on when the last tetanus vaccine was given.
Because spores are so widespread and horses are highly susceptible, tetanus prevention focuses on two things: keeping vaccines current and getting wounds examined promptly by your vet.
How Is Tetanus in Horses Diagnosed?
Your vet usually diagnoses tetanus based on the horse's history and the physical exam. Classic findings include generalized stiffness, a sawhorse stance, lockjaw, third-eyelid prolapse, muscle spasms, and marked sensitivity to stimulation. A recent wound, surgery, foaling injury, or unknown vaccine history makes tetanus even more likely.
In many cases, treatment starts right away because waiting can be dangerous. Laboratory confirmation may be possible in some horses, including testing for toxin, but results are not always fast or consistently helpful enough to delay care. That is why tetanus is often considered a clinical diagnosis.
Your vet may also look for the original wound, assess hydration and nutrition, and check for complications such as aspiration pneumonia, inability to urinate normally, or breathing compromise. Depending on the case, additional testing may help rule out other causes of stiffness or neurologic disease.
The most important step is speed. If tetanus is on your vet's list of concerns, early supportive care and wound management can matter as much as the diagnosis itself.
Treatment Options for Tetanus in Horses
Spectrum of Care means you have options. Here are treatment tiers at different price points.
Budget-Conscious Care
- Immediate farm call or clinic exam
- Wound identification, cleaning, and debridement when possible
- Tetanus antitoxin and tetanus toxoid booster if your vet recommends both
- Antibiotic therapy and basic muscle relaxation/sedation plan
- Dark, quiet stall rest with deep bedding and reduced stimulation
- Home or barn nursing guidance for hydration, feeding, and monitoring
Recommended Standard Treatment
- Hospitalization or intensive ambulatory care directed by your vet
- Tetanus antitoxin, tetanus toxoid booster, and targeted wound care
- Antibiotics, sedatives, and muscle relaxants
- IV fluids or assisted hydration as needed
- Nutritional support and careful nursing in a dark, quiet environment
- Monitoring for aspiration pneumonia, urinary retention, recumbency, and respiratory compromise
Advanced / Critical Care
- Referral hospital or ICU-level equine care
- Continuous monitoring and repeated sedation or infusion-based support
- Advanced airway and respiratory support when available and appropriate
- Tube feeding or intensive nutritional support if swallowing is unsafe
- Management of severe recumbency, pressure sores, aspiration pneumonia, and catheter-related needs
- Extended hospitalization with specialized nursing and complication treatment
Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.
Questions to Ask Your Vet About Tetanus in Horses
Bring these questions to your vet appointment to get the most out of your visit.
- Does my horse's exam fit tetanus, or are there other conditions that can look similar?
- Can you find a likely wound or entry site, and does it need cleaning or debridement?
- When was my horse's last tetanus vaccine, and does my horse need a booster now?
- Should my horse receive tetanus antitoxin, tetanus toxoid, or both?
- Is home care reasonable, or do you recommend hospitalization or referral?
- What signs would mean my horse is getting worse, especially with swallowing or breathing?
- How will we manage pain, muscle spasms, hydration, and nutrition during recovery?
- What cost range should I expect for conservative, standard, and advanced care in this case?
How to Prevent Tetanus in Horses
Prevention is centered on vaccination and prompt wound care. Tetanus toxoid is considered a core equine vaccine, meaning every horse should have it unless your vet identifies a specific reason not to. In adult horses that have already completed their initial series, boosters are generally given every 12 months.
If a previously vaccinated horse gets a wound or has surgery 6 months or more after the last tetanus booster, AAEP guidance recommends revaccination at the time of injury or surgery. Horses with unknown or incomplete vaccine history may need both tetanus toxoid and tetanus antitoxin, depending on the situation and your vet's assessment.
Foals and pregnant mares also need planned protection. Mares are commonly boosted 4 to 6 weeks before foaling to improve colostral antibodies for the foal and to protect the mare around parturition. Foal timing depends on the mare's vaccine status, so it is worth reviewing the schedule with your vet before foaling season starts.
Daily management still matters. Check your horse promptly for punctures, sole injuries, lacerations, and post-procedure swelling or discharge. Clean visible wounds as directed, keep the environment as sanitary as practical, and call your vet early for any wound that is deep, contaminated, near a joint or hoof, or hard to fully inspect.