If you are hauling your horses from your property, biosecurity is important to prevent infectious disease.  Exposing your horses to other horses increases the risk of certain diseases like equine herpes virus, equine influenza and strangles. Vaccinations do not always prevent disease but do decrease severity of clinical signs. The vaccine for equine herpes virus, while usually effective in preventing the respiratory form and abortion, does not prevent the more serious neurological form of the disease. Vaccines to prevent strangles in your horse are available and although routinely recommended, they are not 100% protective. 

Dr. Chris White, DVM, states in the publication “The Horse”, that traveling and showing horses contributes to stress, lowering horses’ immunity and making them more susceptible to disease. The larger the show, the greater chance for disease transmission, as horses may be attending from all over the country. 

It is important to make sure your horse is currently vaccinated by your veterinarian and it’s ideal if your horse attends shows that require vaccinations of all horses.  Prevent your horses from having direct contact with other horses as much as possible, and don’t share equipment like water buckets or brushes with other show attendees.  Giving probiotics can possibly boost your horse’s immunity.  When returning home, always isolate your show horses from the rest of your herd for 3 weeks and monitor their temperatures to make sure they remain normal before adding them back in your herd. Having a separate barn for your show horses would be a good idea during show season.