What to Expect When Vaccinating Horses

What to Expect When Vaccinating Horses

Most side effects of vaccinations are mild and transient, but it’s important to distinguish between minor side effects and those reactions that warrant a call to your veterinarian.

Photo: Erica Larson, News Editor

Many owners understand that vaccinations can help protect their horses from life-threatening diseases. But vaccines can come with side effects due to the immune stimulation they need to create. Most of these effects are mild and transient, but it’s important to be able to distinguish between minor side effects and those reactions that warrant a call to your veterinarian.

“Keeping current with annual vaccinations as recommended by your veterinarian is the best way to help prevent potentially deadly equine diseases and help keep horses healthy,” says Megan Green, DVM, manager of Large Animal Veterinary Services for Merial. “Equally critical is understanding that vaccines are designed to stimulate an immune response, and since your horse is unique, his specific response may be different from other horses.”

Normal Responses

After intramuscular vaccination, it’s fairly common for horses to experience mild, temporary side effects for a few hours. Possible side effects include:

  • Local muscle soreness or swelling;
  • Fatigue;
  • Fever;
  • Loss of appetite; and
  • Lack of energy or alertness.

“Even humans experience signs like this following vaccination,” says Green. “These types of clinical signs help demonstrate that an immune response has been stimulated, which is exactly what we want the vaccine to do.”

However, if side effects last for more than 24 hours, consult your veterinarian as soon as possible to inform them of what is going on with the horse. This will allow your veterinarian to provide you with treatment advice and care instructions.

Causes for Possible Concern

Green cautions that sometimes more serious side effects, and in some cases life-threatening events, can occur, including:

  • Hives;
  • Difficulty breathing;
  • Collapse;
  • Colic; and
  • Swelling at the injection site several days post-vaccination.

“These more serious side effects are rare, but do require immediate consultation, and, in some cases, medical intervention,” she says.

Working with a veterinarian is the best way to ensure your horse is vaccinated based upon its particular needs. Many veterinarians follow the American Association of Equine Practitioners’ recommended guidelines for core vaccinations. Veterinarians can also be helpful in determining the need for other risk-based vaccinations, as determined by an assessment of your geographic threats and travel plans. They are also familiar with the proper handling and administering of vaccines, which is important as improperly handled vaccines can become ineffective or result in an increased risk of side effects.

“With many vaccines available online or through farm supply stores, some horse owners are purchasing and administering their own vaccines to try to save money,” Green says. “Because horse owners are not familiar with vaccine handling protocols, and how to handle adverse reactions should one occur, it’s best to partner with a veterinarian to ensure the horse is receiving the necessary vaccinations and the best overall health care.”

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