MSD Manual

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Sample Vaccination ScheduleforBroodmares*

Sample Vaccination ScheduleforBroodmares*



Core vaccines recommended for all horses


4 to 6 weeks before foaling

West Nile virus

4 to 6 weeks before foaling

Eastern and Western equine encephalomyelitis

4 to 6 weeks before foaling


4 to 6 weeks before foaling

Optional vaccines, depending on local risk

Equine influenza

4 to 6 weeks before foaling

Equine herpesvirus (EHV, rhinopneumonitis)

5, 7, and 9 months of pregnancy using an inactivated EHV-1 vaccine licensed for prevention of abortion; some veterinarians recommend also vaccinating at 3 months of pregnancy


4 to 6 weeks before foaling in geographic regions where botulism causes disease

Equine viral arteritis (EVA)

Serology to check for antiviral antibodies should be done before vaccination; pregnant mares should not be vaccinated; if serology is negative, mares should be vaccinated before breeding to a positive stallion that is shedding the virus; mares must be isolated from other horses for 3 weeks after initial vaccination; positive titers may cause problems if the mare is to be shipped internationally

Rotaviral diarrhea

8, 9, 10 months of pregnancy; for all mares, regardless of vaccination history, in high-volume breeding programs

Potomac horse fever (equine monocytic ehrlichiosis)

4 to 6 weeks before foaling

*Recommendations are for previously vaccinated mares. A different schedule is required if a mare is unvaccinated or vaccination history is unknown.