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Horse vaccinations provide an important management tool

by Wyoming Livestock Roundup

Properly vaccinating horses is important for the well-being of the animals. Vaccinations are designed to protect not only the individual animal but the population of animals. 

Mark Crisman, veterinarian with Zoetis Equine Vet Tech services team, and Beth Davis, veterinarian, associate professor and section head of equine medicine and surgery at Kansas State University College of Veterinary Medicine, recently held a webinar on the discussing the importance of vaccinating horses.

“Vaccination is the administration of some antigenic material that is designed to stimulate the individual’s immune system,” Davis explained. “It primes the immune system, but producers need to remember that no vaccination is 100 percent.”

Also, vaccination is not a remedy for poor management, parasite control and biosecurity. 

“The goal of vaccination is to assist these things in keeping the horse healthy,” Davis explained. 

If a horse needs a particular vaccine annually, she noted that it is important the horse receives it. 

“The annual vaccination reminds the immune system it is supposed to respond a specific way to a specific pathogen,” she explained.

Choosing vaccines

Which vaccines the horse needs depends upon the area the horse lives, what is does, how much it travels, if it is around outside horses and how the horse is managed. Crisman explained that the American Association of Equine Practitioners identified some core vaccines that should be given to all horses. 

“These vaccines, over decades of use, have demonstrated efficacy and safety. We know they will work if they are properly administered,” he explained.

In this group are tetanus, western and eastern encephalomyelitis, West Nile virus and rabies. 

The group also identified a group of risk-based vaccines. Crisman said before giving any of these vaccines, a horse owner should consult with their veterinarian to determine what risk or exposure the horse would have. These vaccines include influenza, herpes, potomac horse fever, strangles and botulism.

“Not every horse will need these vaccinations,” Crisman continued. “But, horses that are on the show circuit, for example, may be more susceptible to respiratory and herpes viruses.”


Most vaccinations are only effective for a year, which is why a booster shot is necessary. For some diseases, the horse may need a booster even more often, Crisman continued. 

“If you are in an area where strangles isn’t an issue, I wouldn’t vaccinate for it. But, if are in a high risk area, I would vaccinate for it annually, or maybe even two times a year.” Crisman explained, adding that he practices in a university town where horses are coming in from all over the country. “Some horses will bring that disease with them, so we may need to vaccinate every six months.”

It is important that core vaccines like tetanus are administered annually. 

“Tetanus can live in the soil, and they can pick it up in their feet or other body organs. Their exposure is different than a dog or human. A horse with tetanus is a horrible thing, and the vaccine is very effective and needs to be given,” Crisman explained. 

Rabies vaccinations are also important because it is a zoonotic disease that can spread from the horse to other animals and even humans. Crisman said it is frequently seen in foals because they are inquisitive and will go right up to the skunk and get nipped on the nose. A series of rabies vaccinations can be given to foals starting at four to six months of age. 

Broodmares may also need to be vaccinated to Equine Herpes Virus-1 (EHV-1) if they are exposed to outside horses and are not in a closed herd. EHV-1 can cause mares to abort. Veterinarians encourage owners to vaccinate the mares against the virus at five, seven and nine months of pregnancy. Some even are vaccinated as early as three months pregnant. 

Administering vaccinations

It is important to administer vaccines in a safe, clean manner or it can cause contamination, irritation or bacterial or clostridial infections, Davis said. 

Davis encouraged owners to thoroughly clean the surface of the skin with isopropyl alcohol. She also recommended having one person hold the horse while the other administers the vaccine. Next, pinch the horse’s skin on its neck and place the needle and syringe. 

After giving the vaccine, aspirate back to make sure there isn’t blood drawn back into the syringe. If the vaccine is administered in a blood vessel, the antigens will be cleared from the horse quickly, and the immune system won’t see any of those antigens, she explained. It is important those antigens go into the muscle. 

Crisman also recommends purchasing vaccinations from a good source. He discourages owners from purchasing vaccinations from farm supply chain stores because the chain of custody is unknown. As an example, if the medicine arrives before Memorial Day, there is a possibility is could sit until after the three-day weekend before it is picked up and put away. The vaccine may have warmed up too much to still be of value. 

“It is important that vaccinations have no breaks in the cold chain,” Crisman said. “It needs to go from refrigeration to administration fairly quickly to be of the most benefit.”

Gayle Smith is a correspondent for the Wyoming Livestock Roundup. Send comments on this article to

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