There are two core vaccinations, rabies and tetanus toxoid. If your horses show or board where there are alot of horses in and out, your vet will recommend the vaccines for contagious respiratory diseases such as Influenza and Rhinopneumonitis. These are associated with local swelling and fever of a few days duration in some horses, as are Potomac Horse Fever and West Nile vaccine. Please ask your vet what your horse needs for its lifestyle and locale and what the potential harmful reactions may be. There are many vaccines on the market, and some of these may not be needed for animals staying in Ontario