Why does my horse need vaccines?

As the old saying goes, an ounce of prevention is worth a pound of cure.  Vaccines help prevent your horse from contracting certain diseases, such as rabies or influenza.  As an owner, it is up to you to communicate with your veterinarian to determine an appropriate vaccine protocol for your horse.

How do vaccines work?

Vaccines carry either modified live or killed antigens for certain diseases in order to stimulate a response from the immune system.  By regularly introducing modified antigens to the immune system, the body will learn to recognize a true infection and react more aggressively.  It is important to recognize that vaccines are not 100% effective.  Proper management against transmissible or contagious disease is crucial in preventing disease outbreak.  Additionally, horses should be considered as individuals and not every horse will respond the same to vaccination in regards to protective response.  Protection against infectious disease is not effective immediately after vaccine administration and requires the appropriate dosing intervals prior to significant exposure.

What if my horse doesn’t leave my property?  Does he need to be vaccinated?


For horses in a closed herd who do not travel, your veterinarian will likely recommend the core vaccines.  These vaccines protect against diseases spread by biting insects, wild animals, and bacterium present in the soil.

My horse frequently travels for shows.  Which vaccines are right for him?

Along with the core vaccines, your veterinarian will recommend additional risk-based vaccines according to your horse’s risk exposure.  Risk factors vary depending on the geographic region you are traveling to and chances of contact with other horses.

What are the core vaccines?

The AVMA defines core vaccinations as those “that protect from diseases that are endemic to a region, those with potential public health significance, required by law, virulent/highly infectious, and/or those posing a risk of severe disease. Core vaccines have clearly demonstrated efficacy and safety, and thus exhibit a high enough level of patient benefit and low enough level of risk to justify their use in the majority of patients.”  The core vaccines are Rabies, West Nile Virus (WNV), Eastern Equine Encephalomyelitis (EEE), Western Equine Encephalomyelitis (WEE), and Tetanus.  These vaccines cover diseases that are spread through biting insects, wild animals, and bacteria present in feces and soils.

What are the risk-based vaccines?

Your veterinarian can help you assess the risks and benefits of additional vaccines and determine if your horse is at risk for other infection diseases not covered by the core vaccines.  The risk-based vaccines include Potomac Horse Fever, Botulism, Rhinopneumonitis, Influenza, Leptospirosis, and Strangles.  These vaccines cover diseases that are spread through direct contact with other horses and via organisms not widely found or only found in certain regions.

Do broodmares need different vaccines than other adult horses?

Yes, broodmares have a different vaccination protocol than other adult horses.  Broodmares should be vaccinated 4-6 weeks prior to foaling to protect the mare and initiate passive transfer of antibodies to the foal through the colostrum.


For a complete guide to vaccines, download the Vaccinations for Adult Horses guidelines.

(adapted from the American Association of Equine Practioners Adult Horse Vaccination Chart. http://www.aaep.org/custdocs/Adult%20Vaccination%20Chart_8.12.16.pdf)