Ask an Expert

Vaccinations for Weanlings

July 4, 2011

Dr. Tom Lenz weighs in on the proper vaccines for weanlings.


I bought a mare and was not told that she could be possibly pregnant. In August of last year, I gave her a six-way shot, and that was all she got for shots. In March, she foaled and had an awesome little stud colt. I was wondering what shots I need to give him to make sure he stays safe and healthy, and how old does he need to be to get the West Nile virus vaccine?


Foals should begin a series of three vaccinations at around 4 to 6 months of age.  If the mare was vaccinated four to six weeks prior to foaling, he can wait until he’s 6 months old to start the shots.  If she was not vaccinated four to six weeks prior to foaling, he should receive the first vaccination for tetanus/eastern and western equine encephalitis/West Nile virus at 4 months of age.  A second booster vaccination should be given three to four weeks later, and then a third when he’s a yearling.  If you’re going to show the foal, you should vaccinate him against rhino (EHV-1 and EHV-4), plus influenza, at around 9 months of age.  It’s also a good idea to vaccinate the foal against rabies.

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Remember: your local veterinarian is the best source of information on vaccinations in your specific part of the country.

— Dr. Tom R. Lenz
Senior Director, Equine Veterinary Services
AQHA Corporate Partner Pfizer Animal Health