Equine Information and Horse Diseases

Planning a disease prevention program for your horse is an important aspect of owning a horse. Infectious diseases can result in increased veterinary fees, loss of revenue from sales and shows, and loss of use or death of the animal. Additionally, since many horses are kept as recreational animals and/or a member of the family, there is often an emotional cost when the animal becomes ill or dies. Routine health care and vaccination programs can help prevent horse diseases. A healthy horse free of disease is usually alert, active, and responsive to noises and visual stimuli.

Either a lethargic attitude or extreme excitability may indicate illness. Prompt treatment of horse diseases usually lessens the severity and duration of the disease.

One basic component of any good horse health program is a complete vaccination program. When designing a vaccination protocol, one should remember that the success of the preventative herd health program is no better that the health of the individuals within the herd. The introduction of horses with unknown immunization should be restricted until proper confirmation of immunization or vaccination is done.

One common failure of a horse health program is inaccurate record keeping. This documentation must be done to ensure success of the vaccination program.

Remember, vaccination does not offer immediate protection because the body takes 2-4 weeks to produce protective antibodies against the vaccinated disease(s). First time vaccinations must be boostered with a second vaccination 2-4 weeks later to strengthen the protective response.

Disease	Administration	Comments
Tetanus Toxoid	Initial dose with booster in 3-4 weeks. Annual booster.	Local tissue reaction; anaphylaxis (shock) in some horses.
Tetanus Antitoxin	Use in non-immunized horses or horses of unknown history at time of injury	Short term protection for 7-14 days.
Botulism	Before exposure in enzootic areas.	Local tissue reaction; anaphylaxis (shock) in some animals. Heat and minor swelling may occur at the injection site.
Encephalomyelitis (Eastern, Western, & Venezuelan)	Initial dose with booster in 3-4 weeks. Annual to biannual booster.	Do not stress horses recently vaccinated for Venezuelan encephalomyelitis. Vaccination for Venezuelan encephalomyelitis may limit exporation.
Rabies	Horses must be older than 3 months of age. Booster annually.	Local tissue reaction may result if injected subcutaneously.
Influenza	Initial dose with booster in 3-4 weeks. Biannual for low to moderate risk horses. Every 2-3 months for high risk horses.	Do not vaccinate 2-3 weeks before a stressful event. Some horses have a brief fever, loss of appetite, and depression after vaccination.
Potomac Horse Fever	Initial dose with booster in 3-4 weeks. Revaccinate every 4-6 months in enzootic areas, otherwise annually.	Local tissue reaction may occur at injection site.
Strangles	Initial dose with one to two boosters 2-4 weeks later (depending on the vaccine) with annual booster.	Biannual vaccination of young horses at risk may increase risk of anaphylaxis (shock). Some horses may have Postvaccinal reactions or abscesses at the site of injection which may be combated with exercise and antibiotics. Vaccination does not always prevent infection and clinical signs.
Rhinopneumonitis (EHV-1 & WHV-4)	Initial dose with booster in 4-6 weeks. Annual booster.	Deep intramuscular injection in hind leg. Use a vaccine that contains EHV-1 and EHV-4 strains. Mild exercise to promote absorption is recommended for one week after injection.
Anthrax	Initial dose with booster in 2-3 weeks and 2-4 weeks before an expected anthrax exposure. Annual booster.	Do not vaccinate horses undergoing antibiotic therapy. Use entire contents when first opened then burn container and any unused vaccine. Local tissue reaction expected; inject under mane. Placing horse in a dark stall for 10 days may be beneficial. Not a routine vaccination.
Equine Viral Arteritis	Vaccinate at any time, except foals younger than 6 weeks of age and stallions 3 weeks before breeding. Vaccinate open or maiden mares but at least 3 weeks before breeding.	Horses may have mild fever and decrease in white blood cells after vaccination. Burn container and any unused vaccine. Not a routine vaccination