"Healthy as a horse” starts with spring vaccinations. As horses are exposed daily to the environment, wildlife and mosquitoes that transmit the five core equine diseases, it’s important to follow the American Association of Equine Practitioners (AAEP) core equine disease vaccination protocol. Make sure horses are vaccinated yearly against Eastern and Western equine encephalomyelitis, West Nile virus, rabies, and tetanus.
Veterinarian visiting a farm to vaccinate horses.
Reactions that horses develop to a vaccine are due to the horse’s immune system responding to the vaccine and they are generally mild, self-limiting and often don’t require treatment.
© 2020 by OIE Bulletin-John Grewar
The American Veterinary Medical Association (AVMA) defines core vaccinations as those “that protect from diseases that are endemic to a region, those with potential public health significance, required by law, virulent/highly infectious, and/or those posing a risk of severe disease.”
Vaccinations are the foundation of your horse’s preventive health program, accompanied by deworming of course, which as a general best practice adult horses should be dewormed twice yearly – during spring and fall. Vaccinating horses during the spring helps to safeguard them ahead of peak activity from carriers of such diseases, like mosquito-transmitted diseases threatening horses with mortality rates up to 90%.
The three big equine diseases transmitted by mosquitoes are West Nile virus, Eastern equine encephalomyelitis, and Western equine encephalomyelitis. Venezuelan equine encephalomyelitis isn’t typically a problem in the United States, but there have been years with outbreaks in specific areas. These diseases can attack and inflame a horse’s nervous system.
It is important for your horse to be protected, so let’s look at the basics of vaccinating horses.
Vaccine selection – Every horse should receive the five core vaccinations, Eastern and Western equine encephalomyelitis, West Nile virus, rabies, and tetanus, a minimum of once per year. Additionally, horses with compromised immune systems (systemic diseases such as Cushing’s) or those in high-risk areas (long mosquito vector seasons) might benefit from twice-yearly vaccination.
In addition to the core vaccines, there are risk-based vaccinations available. There are several available, but the most common risk-based vaccinations protect against rhino, influenza, strangles, and Potomac horse fever. It might seem obvious, but determining whether your horse should receive these vaccines depends entirely on their risk of exposure.
For example, Potomac horse fever occurs most commonly in certain geographic areas, so if your horse resides in a historically endemic location, then they should be vaccinated. Similarly, rhino, influenza and strangles are all respiratory illnesses that are spread by exposure to other horses or fomites contaminated by other horses. If your horse never leaves your farm and isn’t exposed to horses outside of your farm, then they may not need protection against these diseases.
If you regularly travel, send your horse to a trainer, go on trail rides or board your horse, then your horse would benefit from vaccination. If you have any questions in deciding whether your horse would benefit from any risk-based vaccines, your veterinarian would be a great resource.
Storage – It’s important to read and follow the vaccine’s label for proper storage and handling for the vaccines you select for your horse. In general, however, vaccines should be stored at a temperature of 35 to 45 degrees F and never frozen.
AAEP’s “Vaccination Guidelines” and “Vaccine Storage and Handling” serve as an excellent resource for horse owners. In the Guidelines, they offer great tips well worth mentioning here, including:
- Monitor vaccine fridge temperature
- Keep vaccines in the middle of the refrigerator for temperature consistency, not in the door or far back
- Organize vaccines according to expiration date
Where to stand – When we are administering injections, I always recommend that the horse be held by a handler and not tied up. You want your handler standing on the same side as you, so if the horse jumps off to the side, both you and the handler are safe.
Needle size – When we’re talking about needle selection for intramuscular injections – depending on the thickness of the medication or vaccine that we’re administering – we typically use an 18-to-20-gauge, 1.5-inch needle.
Injection site – For injections, my preferred site is going to be the neck, and we want to stay within that injection triangle which is in front of the shoulder blade, above the vertebra column and below the nuchal ligament. If the injection site is dirty, we want to make sure to brush and clean that off before we administer the injection. We don’t need to use alcohol or disinfectant over the injection site before we administer the vaccine.
Some horses don’t like to get poked, so sometimes I’ll recommend that you remove the needle from the syringe before you administer it and using your hands, kind of desensitize the area within the injection triangle with some vigorous rubbing, scratching and tapping. You’ll want to have the needle in your hands when you’re doing that so with one swift motion, you can poke the horse as a practice run.
After you have desensitized the area following the steps above, you can attach your syringe to it and administer the injection in the same area. Another trick is that if you don’t want to remove the needle, to desensitize the area you can pinch some skin to help distract the horse and administer the injection.
Safety – Vaccines go through rigorous testing for safety before being brought to the market and they serve as an important precaution against disease risks. After receiving a vaccine intramuscularly, it is possible for some horses to demonstrate lethargy, fever, swelling and soreness in reaction to the vaccine (much like people).
The reactions that horses develop to a vaccine are due to the horse’s immune system responding to the vaccine. They are generally mild, self-limiting and often don’t require treatment. Forcing exercise for 20 to 30 minutes twice daily for three days after vaccination will help to minimize muscle soreness. If your horse has a severe reaction, such as severe lethargy, hives or abscess formation, you should contact your veterinarian immediately. Horse owners can submit vaccine reactions to vaccine manufacturers, too.
Keep these thoughts in mind as you shield your horse from disease risks. Visit ValleyVet.com to continue learning about horse health.
About the author: Valley Vet Supply Consulting Veterinarian, Tony Hawkins, DVM, attended Kansas State University’s College of Veterinary Medicine. In addition to his role on the Technical Service team at Valley Vet Supply, Dr. Hawkins owns a mixed-practice veterinary clinic in Northeast Kansas and is treasured by the community for his care across species. He is greatly involved in cattle health, including processing and obstetrical work, as well as providing hands-on care for horses and pets through wellness appointments and surgery.
About Valley Vet Supply
Valley Vet Supply was founded in 1985 by veterinarians to provide customers with trusted animal health solutions. Building on over half a century of experience in veterinary medicine, Valley Vet Supply serves equine, pet and livestock owners with thousands of products and medications. With an in-house pharmacy that is licensed in all 50 states, and verified through the National Association of Boards of Pharmacy (NABP), Valley Vet Supply is the dedicated source for customers’ horse, livestock and pet needs. For more information, please visit ValleyVet.com.
Article by By Tony Hawkins, DVM, Valley Vet Supply Consulting Veterinarian - Press release by Aimee Robinson