Vaccinate horses this spring

Farm Forum

BROOKINGS – Springtime is an excellent time for horse owners to vaccinate their horses against threats from infectious diseases, says Russ Daly, SDSU Extension Veterinarian and State Public Health Veterinarian.

“Many of the infectious diseases of importance, such as West Nile Virus or Equine Encephalomyelitis (sleeping sickness) are transmitted by insects that become active in the spring,” Daly said. “Others are transmitted between horses, and spring and summer activities are more apt to bring horses from different locations into contact with one another.”

Core and risk-based vaccines

The American Association of Equine Practitioners (AAEP) provides guidelines for the vaccination of horses. Rebecca Bott, SDSU Extension Equine Specialist explains that vaccinations are grouped into core or risk-based vaccinations.

“Core vaccinations are recommended for all horses, while certain risk-based vaccinations are strongly recommended for horses that travel, mingle with other horses, or live in regions were the risk of a certain disease is high,” she said.

Core vaccinations include diseases such as tetanus, sleeping sickness, West Nile Virus, and rabies. Risk-based vaccinations may include diseases such as rhinopneumonitis (Equine Herpesvirus-4), influenza, and others.

She reminds horse owners that the first time a horse is vaccinated for a specific disease they may need booster vaccinations to help the immune system develop a full response to disease-causing organisms.

“After the initial series, most vaccinations will be given annually or semi-annually to help maintain this level of protection in the horse,” she said.

Equine herpesvirus

Forms of equine herpesvirus causing neurologic signs have emerged in various places around the country. Dustin Oedekoven, South Dakota State Veterinarian, says that horse owners with horses that will come in contact with other horses should consider vaccination against Herpesvirus infections.

Vaccinations for both EHV-1 and EHV-4 are available; however, there is not a vaccine to prevent the neurological signs associated with EHV.

“Your local veterinarian should be able to help you determine which EHV vaccinations to select and how often to vaccinate based on the specific risk factors for your horse,” he said.

Horses that are frequently traveling and coming into contact with other horses should likely receive boosters every 90 days. Since EHV-1 can cause abortion in pregnant mares, Oedekoven says those animals should be vaccinated at five, seven and nine months of gestation with an EHV vaccine that is labeled for prevention of equine abortion.

West Nile virus

West Nile virus is established in South Dakota. An effective vaccine is available and should be a part of the core vaccination schedule for horses in South Dakota.


In 2012, three horses in South Dakota were diagnosed with rabies. Rabies is established in the skunk population in South Dakota, making rabies vaccination for horses a recommended procedure.

To decide which vaccines are best for your horse, Oedekoven encourages horse owners to work with their local equine veterinarian.

“Many factors such as location, age of horses, and use will be taken into account when planning the best strategy for protecting your horses against common equine diseases. If you think your horse may be suffering from any of these conditions, contact your veterinarian at once,” Oedekoven said.

For more information, visit and view the iGrow Quick Reference: Vaccination of Horses, or contact Russ Daly, SDSU Extension Veterinarian,, Rebecca Bott, SDSU Extension Equine Specialist,, or Dustin Oekekoven, State Veterinarian,