Ask Your Veterinarian Presented By Kentucky Performance Products: Switching Vaccine Sources by Paulick Report Staff|04.03.2020|1:09pm Veterinarians at Rood and Riddle Equine Hospital answer your questions about sales and healthcare of Thoroughbred auction yearlings, weanlings, 2-year-olds and breeding stock. QUESTION: Since some veterinarians and farms use different types of vaccines, is it a problem to buy an individual and start it on another type? DR. KEVIN HYDE: The short answer to this question is no. In this day and age, vaccines from all of the major pharmaceutical companies have a significant amount of research behind them and do a good job of protecting our horses from the diseases they were created against. Is there one vaccine that is slightly more effective than another? Maybe. But if you feel more comfortable with one brand or line of vaccine than another and it has done a good job on your farm, there is no reason you can't switch a new horse over to the brand you are comfortable with. Dr. Kevin Hyde In an ideal world, we would always get the complete vaccine history from the previous owner and could just continue giving the same vaccine without missing a beat. Unfortunately, more times than not, we don't get a complete history and there can be questions about how well the horse has actually been vaccinated. In these cases, we should probably treat the horse as if it has never been vaccinated. We should begin vaccinating with the initial series recommended by the manufacturer to ensure that an adequate immune response is initiated to protect our new horse. After that, the new horse can be placed on the routine vaccine schedule you have put together with your veterinarian for your particular farm. Even if we know the vaccine history and still decide to switch to a vaccine we are more comfortable with, we should use the recommended initial series for that vaccine. This is to ensure that the levels of protective immunity are reached for that specific vaccine. Because each vaccine works slightly differently to create an immune response, the full recommended series may be needed to get to the levels of immunity to be protective. There are a couple of other things to think about when selling or buying a horse at a public sale. Sales and long-distance transport can be very stressful for a horse. Stressful events such as this can reduce the level of immune response that a horse will have in response to being presented with an infectious agent. If selling a horse, it is really important to vaccinate early enough to give the horse's body adequate time to build up protective immunity prior to the sale. If buying a horse from a sale, we need to realize that their protective levels may have been lower during that “stressful” event and treat the new horse accordingly. This includes effective biosecurity measures and herd health practices to protect all of the horses on the farm. Once the new horse has settled in at the new farm, it is important to get them vaccinated as soon as possible, before being introduced to the rest of the herd if possible. Every farm has slightly different needs, but every horse needs to receive, at a minimum, the “core” vaccines recommended by the American Association of Equine Practitioners (AAEP). We do have to remember that no vaccine is perfect and can't be guaranteed to prevent 100% of infections. But by following the manufacturer's guidelines, under the direction of our veterinarians, we will have the best chance for success. Dr. Hyde graduated from the Washington State University School of Veterinary Medicine in 2005. He completed an internship at Rood and Riddle Equine Hospital in 2006 and then became an associate with the practice for five years. Dr. Hyde became a shareholder at Rood and Riddle at the beginning of 2019.