Previously Unvaccinated Horses
Vaccinate all previously unvaccinated adult horses in March/April with a two-dose primary series, three to four weeks apart. Avoid vaccinating pregnant mares in the first trimester of gestation. Talk to your veterinarian about vaccinating pregnant mares after the first trimester.
Vaccinate all young horses (less than one year of age) in March/April with a three-dose primary series. Allow three to four weeks between doses 1 and 2, and allow six to eight weeks between doses 2 and 3.
If the foal was born to an unvaccinated mare or a mare that was not booster vaccinated four to six weeks before foaling, begin the vaccination series at three months of age. If the foal was born to a mare that was booster vaccinated within two months of foaling, then begin the vaccination series at four to six months of age.
Vaccinated Horses
If your horse was fully vaccinated last year or if the primary vaccination series was completed this year, follow up with a booster every six months. When the first equine WNV case is identified in California, booster all horses that have not been vaccinated within the previous six to eight weeks, then follow with boosters every six months from the date of the last vaccination.
For more information visit the UC Davis Center for Equine Health .
