McKee-Pownall Equine Services | Health Care FAQ

Health Care FAQ

What guidelines do you have for vaccinating my Horse

Every horse is a unique individual with specific requirements and this is a general guideline to the vaccines that are available to prevent some of the diseases found in Southern Ontario. Please talk to your veterinarian about a tailored vaccination program for your horse.

While some vaccines are available as a combination shot that covers 5-6 diseases in one injection, we have found a higher rate of reaction (sore necks, fever) after using the multi-antigen products. In general, we think it is better for the horse to break up the vaccines into two sessions, to avoid excessive immune stimulation and reduce side-effects. In addition, this allows us to tailor the vaccination program more precisely for each individual.

Core Vaccines- suggested for all horses:

Tetanus: Tetanus occurs when Clostidium tetani, a bacterium found throughout the soil, gains access to the body through a wound. As it multiplies in the tissues, it produces a potent neurotoxin that causes severe muscle spasms, rigidity, and death. Vaccination protects against the disease.

Rabies: A 100% fatal virus, frequently found in wildlife in Southern Ontario, that is spread by infected saliva in bite wounds. Horses are exposed through unnoticed bites on the nose and legs, and can have signs varying from semi-comatose states to intense aggression. In addition to potentially dangerous behaviour, horses can pass the rabies virus to humans. Outdoor turnout is not a prerequisite for infection, as rabid wildlife can behave erratically and can wander into stables (this occurred at a racetrack several years ago).

West NileVirus: Carried by birds and spread through mosquito bites, WNV causes fever, tremors, and other neurologic signs. Although the initial outbreaks occurred in 2000, there is a persistent wildlife reservoir of this virus in Southern Ontario and we continue to document clinical cases in horses. Many insurance companies require documentation of WNV vaccination.

Eastern/Western Equine Encephalitis:  EEE and WEE viruses are also spread by biting insects and cause signs similar to WNV. Several cases were diagnosed in 2011 in the Northeastern US.

Additional vaccines recommended for horses under certain conditions:

Influenza/Rhinopneumonitis (EHV):Both are highly contagious viral respiratory diseases that are spread from horse to horse through nasal secretions. Certain strains of EHV can cause devastating neurologic disease and abortion. Vaccination for these diseases is recommended a minimum of every 6 months in order to prevent significant respiratory disease and reduce shedding of infectious virus to other horses. FEI regulations require all horses to have a booster every 180 days but not within 21 days of a horse show. Flu/Rhino is recommended for horses who show, travel, or live at a farm where other horses come and go from the property. Broodmares should receive EHV boosters every 2 months throughout pregnancy to prevent herpesvirus abortion and fading foals.

PotomacHorse Fever (PHF):This organism causes life-threatening diarrhea, fever, and laminitis. It resides in aquatic snails but can be transmitted by flying insects that are ingested by horses in their forage, either while grazing or in hay. Horses living in low-lying areas with standing water are particularly at risk, and there was a flare-up of this disease in the northeast Toronto area last year. There are endemic pockets of PHF that persist in Southern Ontario every year. Annual vaccination will reduce the severity of clinical signs if your horse contracts this disease

Strangles: Highly contagious bacterial infection of the upper respiratory tract, causing purulent nasal discharge and lymph node abscesses. The most reliable vaccine is made from a modified version of the live bacteria that is sprayed into the nostril. This vaccine does carry some risk of reaction, particularly in horses that have been exposed to Strangles in the past. If previous exposure is suspected, antibody levels can be measured in the blood to determine if the horse is a candidate for vaccination. There are outbreaks of Strangles in Southern Ontario every year.

Botulism:Increasing use of ensiled forage (haylage) for horses with digestive and respiratory problems, as well as the feeding of round bale hay, place horses at risk of exposure to the botulinum toxin. The bacteria that produces this toxin thrives in moist, anaerobic (lack of oxygen) conditions that typically occur during the ensiling process. Anaerobic conditions can also occur inside round bales, although this is fortunately less common. Botulinum toxin causes a progressive paralysis (think botox) that results in flaccid muscles and eventual death from suffocation when the respiratory muscles are affected. There are over 7 strains of botulism but forage-acquired disease is typically caused by type B, and there is a vaccine available to protect against this strain. An initial series of three injections is required followed by annual boosters. If you plan to feed haylage this vaccine is strongly recommended, as botulism costs thousands of dollars to treat and is usually fatal even with aggressive intervention.