Which Vaccinations Do My Horses Need?

Written By: The Irongate Equine Team

Written By: The Irongate Equine Team

As a horse owner, it’s hard to keep up with equine vaccination recommendations. Protocols change frequently based on newly available vaccinations, new research, or outbreaks that require additional care. More and more, our vaccination recommendations are becoming what we call risk-based recommendations. This means that there is no “one size fits all” attitude regarding vaccination and we should instead base our recommendations on an evaluation of your horse’s individual needs. For example, does your horse travel or stay at home? Do your horse's pasture/barn mates travel frequently? What area of the country are you located in? Are there cost considerations to keep in mind? What’s the environment like at the barn and in the pastures? Essentially, asking the following three questions will help dictate what vaccinations your horse receives:

  1. What does he do?

  2. What are the other horses around him doing?

  3. What are his risks?

Knowing that the following are generic, all inclusive recommendations, here are Irongate Equine Clinic’s vaccination protocol recommendations:

EWT/WN (annual – Spring)

This is what we call a four way vaccine, which combines multiple vaccines in a single intramuscular (IM) injection. EWT/WN vaccinates against Eastern and Western Encephalitis, Tetanus, and West Nile Virus. You can give each of these vaccinations separately, but the convenience of a single IM shot is appealing and as effective as the individual shots. Eastern and Western Encephalitis and West Nile are all carried and spread by mosquitoes. They also have similar symptoms, resulting in inflammation of the brain and/or spinal cord and neurologic symptoms. Tetanus is a bacteria that is carried on most soil and other surfaces. Horses are highly susceptible to tetanus, making this an important vaccination to get for your horse every year.

Rabies (annual – Spring or Fall)

Rabies is carried by susceptible animals – in Wisconsin, that means bats, skunks, and raccoons, primarily. Horses are susceptible to it, and it is 100% fatal as there is no cure or treatment. Every once in a blue moon, a horse will survive, much to the surprise of the medical world. As such, the American Association of Equine Practitioners includes it as one of the “core” vaccines every horse should receive annually. Rabies can present in horses with neurologic issues, making the horse seem “dumb”. Because there are so many equine conditions with neurologic symptoms, any horse that dies following neurologic episodes is a candidate for rabies testing, and should be handled with extreme caution in order to limit the exposure to rabies.

Flu/Rhino (semi-annual – Spring and Fall)

The Influenza/Rhinopnuemonitis vaccine is not one of the “core” vaccines recommended by AAEP, but is highly recommended on a semi-annual basis, particularly for horses who travel. Flu and Rhino are both respiratory diseases which are contagious from horse to horse. Some barns may not vaccinate against Flu/Rhino at all, or only do so once a year. Remember, vaccinations should be risk-based. If your herd is largely isolated and rarely travels, the Flu/Rhino vaccine may be unnecessary. While this is an IM vaccine, there is also a very popular intranasal vaccine for influenza.

Strangles (annual – Spring)

Strangles is a bacteria that causes a regional and systemic abscessation of the lymph nodes, which leads to pirulent or pus discharge from the nostrils. Your horse will have a high fever and you’ll often hear a hacking, strangled sound when he breathes, hence the name. Strangles is not typically life-threatening, although it can be. It can be life threatening when the bacteria affects internal lymph nodes or if regional lymph nodes in the throat latch swell and occlude the airway. The vaccine comes in two forms – the modified live virus, which is intranasal, or the killed virus, which is given in an IM shot. The modified live virus is efficacious, and the form we recommend at IEC. 

Potomac Horse Fever (semi-annual – Spring and Fall)

Potomac Horse Fever (PHF) is a regional bacteria whose range continues to spread. It’s a bacterial infection that horses acquire through the digestion of dead mayflies and other insects. There has recently been an increase in incidents of PHF in south central Wisconsin, although it is still relatively rare. The vaccination that is available is of questionable efficacy, and only vaccinates against a single form of the infection, of which there are many. Those horses that do acquire PHF but have been vaccinated seem to become less ill than those who were never vaccinated, so we do recommend you vaccinate your horse against PHF. To read more about Potomac Horse Fever, go to our article dedicated to that PHF, or give us a call.

Rhinopneumonitis (as needed during pregnancy)

The final vaccine we recommend is again for Rhinopneumonitis. However, this is the form of the virus that infects pregnant mares and causes an abortion, or loss of pregnancy. There are two varieties of this rhino vaccine, Prodigy and Pneumabort K. These vaccines are highly effective in preventing the loss of pregnancy due to the rhino infection. Your pregnant mare should receive this vaccine at five, seven, and nine months of pregnancy. 


To recap, your horse should at least receive EWT/WN and Rabies vaccinations once a year. In general, we recommend that your horse receive EWT/WN, PHF/Rabies, Strangles, and Flu/Rhino in the Spring, and PHF and Flu/Rhino in the Fall. Based on your horse’s risk factors, you may be able to eliminate some vaccines – always speak to your veterinarian to determine the best plan for your horse.

We are here to help! Contact us if you have any questions regarding your horse’s vaccination schedule.

Frequently Asked Question

Is there a better time(s) of year to give the shots. Is it different if you have a show horse or if your horses stay at home?

The quick answer is that timing of shots is important. For example, vaccines that aid in the prevention of disease transmitted by mosquitoes should be done prior to the beginning of the mosquito season – in Wisconsin, we try for early spring April/May. Other diseases, such as Rabies or Strangles, could have exposure risks year-round so the time of vaccine administration is less critical. For some diseases, like Influenza and Rhinopneumonitis, vaccination twice annually is indicated and usually corresponds with your horse’s travel plans or exposure risks. Current recommendations do account for your individual horse’s exposure risks and speaking with your veterinarian should ensure optimal vaccine selection.