With a selection of horse vaccines readily available on local feed store shelves, purchasing a handful for use in your barn might be something you're considering. But are there health risks posed to your horse lurking behind a choice to forgo your veterinarian's spring vaccination visit this year? Here are five points to consider when planning your spring vaccinations, and issues related to each.

1. Which vaccines does your horse need?

Common spring vaccinations generally include Eastern and Western encephalomyelitis, West Nile virus, tetanus, and rabies. How old is your horse and what does he do for a living? Is he going to be traveling and has he had any reactions to vaccines in the past? There are many pieces to the puzzle that your veterinarian fits together to tailor a vaccination plan for your horse. For example, a younger and more susceptible horse might not need the same vaccines as an older horse with a stronger immune system (developed through exposure to many respiratory pathogens over the years). If your horse does not travel but others within the same barn do, he might still require vaccination for communicable diseases (such as strangles or equine influenza). Your travel plans for your horse might also determine if region-specific vaccines such as those for Potomac horse fever, botulism, and Venezuelan equine encephalitis are recommended. A veterinarian will be able to design the ideal vaccination program and provide all the necessary vaccines for the horses in your barn.

2. Is your horse fit to be vaccinated?

Vaccination visits are an opportunity to have your veterinarian perform an annual physical examination on your horse and address any concerns you have about your horse's health. Vaccine efficacy is dependent on an animal's ability to launch an appropriate immune response, and a veterinary examination can identify underlying health issues that could contribute to an adverse reaction or vaccine failure (see below). It is safer and more beneficial to wait until the veterinarian deems these horses healthy enough to vaccinate.

3. What if your horse has a vaccine reaction?

Adverse vaccine reactions can range from local swelling at the vaccination site to colic. In some rare cases, death from anaphylaxis is a possibility. Anaphylaxis is a rapidly developing, exaggerated allergic reaction characterized by a drop in blood pressure, difficulty breathing, and collapse. Some horses' immune systems produce antibodies in response to components of the vaccine's carrier (also called an adjuvant) in the vaccine. A horse might even develop antibodies against the adjuvant of one particular vaccine, leading to an adverse reaction to another vaccine's adjuvant. In the event of an immediate anaphylactic reaction, a veterinarian's presence could save your horse's life. Your veterinarian can sometimes even predict potential adverse events and prevent them from occurring in a sensitive horse by performing intradermal skin testing with the vaccine ahead of time, noting a reaction at the site of injection in the skin.

4. What if the vaccine fails?

Unfortunately, immunizations are not 100% effective in every horse. Some vaccine manufacturers provide a guarantee for their products in which diagnostic and treatment costs are covered in the event of a vaccine failure, provided a veterinarian has administered the vaccine.

5. Vaccination guidelines have not changed for many years ... have they?

As new infectious disease research developments and vaccine innovations continue to emerge, vaccination recommendations are constantly changing. Part of your veterinarian's role is to guide your vaccination decisions based on recent developments and their professional experience.

Vaccines are not innocuous products, and veterinarians use a wealth of research and experience to generate vaccination guidelines for horses. Although it might be easy and inexpensive to buy your vaccines as you are shopping for grain and supplements for your horse, be aware of the advantages a valid veterinary-client-patient relationship has to offer before making decisions about spring vaccination selection and administration.


Further Reading:

Special Report: Vaccines for Horses
Video: Horse Vaccination Basics
Vaccination Basics for Horses
Vaccinations an Investment in Equine Health

About the Author

Jean-Yin Tan, DVM, Dipl. ACVIM

Board-certified in internal medicine. Professional interests include neonatology, respiratory disease, and gastroenterology.

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