Preparing to administer a vaccine to a horse


With a well-planned vaccination schedule, you can help protect your horse against a range of infectious diseases. Horse vaccines are an inexpensive, preventative measure in horse care. Coupled with solid animal husbandry, vaccines help ensure your horse leads a long and healthy life.

A vaccine contains a pathogen (virus, bacterium, or parasite) in an altered state, stimulating the horse's immune system to produce antibodies. Once antibodies develop, the horse is better equipped to fight off the actual pathogen if exposed. Without immunity, a horse may become seriously ill or die.

Immunity duration varies by disease. For example, a rabies vaccine typically provides about one year of protection, while an influenza vaccine may only protect for several months due to virus mutations. Revaccination, or booster shots, are required for continued protection.

Horses may feel sore or lethargic after vaccination. Allow several days of rest post-vaccination, ideally at least two weeks before any stressful event, such as competition travel. Spacing vaccines over several weeks can reduce stress on the immune system and optimize antibody development.

Selecting Diseases to Vaccinate Against

Always consult your equine veterinarian to determine appropriate vaccines, particularly for horses with chronic medical conditions (Cushing's Disease, insulin resistance, laminitis), geriatric horses, broodmares, or foals. Foal vaccination timing depends on the dam's vaccination status and colostrum intake. Your veterinarian can assess risks and create a vaccination schedule with booster timing.

The American Association of Equine Practitioners (AAEP, www.aaep.org) classifies vaccines as Core or Risk-Based.

Core Vaccines

  • Tetanus
  • Rabies
  • Eastern/Western Encephalomyelitis
  • West Nile Virus

Risk-Based Vaccines

Administered based on exposure risk and veterinarian recommendation:

  • Anthrax
  • Botulism
  • Equine Herpesvirus (Rhinopneumonitis)
  • Equine Viral Arteritis
  • Equine Influenza
  • Potomac Horse Fever
  • Rotaviral Diarrhea
  • Strangles

Overview of Core and Risk-Based Diseases

Tetanus – Nearly always fatal, tetanus affects muscles and nerves. Muscles in the neck and jaw may become rigid, and legs stiff. Caused by bacteria found in soil, it enters through puncture wounds or the umbilicus of foals. Annual vaccination and booster for deep wounds is recommended.

Rabies – Always fatal, transmitted via saliva of infected animals. It attacks the central nervous system, causing behavioral changes. Annual vaccination and boosters after confirmed bites are recommended.

Eastern/Western Encephalomyelitis – "Sleeping sickness" caused by virus strains transmitted by mosquitoes. Severity varies by strain, but annual vaccination before mosquito season is recommended. Often combined with tetanus vaccine.

West Nile Virus – Mosquito-borne virus affecting the central nervous system. Horses may die or have residual effects. Annual vaccination before mosquito season is recommended.

Anthrax – Caused by Bacillus anthracis, survives in alkaline soil. Infection occurs via inhalation, ingestion, or wounds.

Botulism – Caused by Clostridium botulinum toxins, leading to paralysis. Infection via ingestion or wounds; often fatal.

Equine Herpesvirus (EHV) – Respiratory disease caused by EHV-1 and EHV-4. EHV-1 can cause abortion and death. Highly contagious.

Equine Viral Arteritis (EVA) – Contagious virus causing abortions, pneumonia, and carrier status in stallions. Usually not life-threatening to healthy horses.

Equine Influenza – Highly contagious respiratory virus. Symptoms include fever, cough, and nasal discharge. Vaccinate horses traveling or in open herds; boosters may be needed.

Potomac Horse Fever – Caused by bacteria hosted by freshwater snails and insects. Occurs late spring to early fall. Symptoms include depression, fever, colic, diarrhea, laminitis, and possible death.

Rotaviral Diarrhea – Infectious diarrhea in foals. Untreated cases may be fatal.

Strangles – Highly contagious bacterial infection (Streptococcus equi). Causes swollen lymph nodes and abscesses. Rarely fatal but may persist in carriers.

Tips to Supplement Your Vaccine Program

  • Remove standing water to reduce mosquito breeding.
  • Keep horses indoors at dawn and dusk when mosquitoes are most active.
  • Keep lights off at night to avoid attracting bugs.
  • Use screens on barn windows and doors.
  • Disinfect water and feed tubs regularly.
  • Require a veterinarian's health certificate for new horses; segregate for at least two weeks.
  • At equestrian events, use personal feed and water tubs; prevent grazing in common areas.
  • Use insect repellents on horses and handlers.
  • Prevent overcrowding; provide clean water and quality feed.

Source: American Association of Equine Practitioners (AAEP) – www.aaep.org