In autumn, check three vaccinations: the equine influenza booster (required for most competitions), tetanus (rarely compulsory but life-saving) and EHV, or rhinopneumonitis, especially for in-foal mares, which are vaccinated in the 5th, 7th and 9th month of pregnancy. Review your whole yard with your vet before winter.
This guide follows the Northern Hemisphere breeding season. In the Southern Hemisphere, shift the months by about six.
Which horse vaccines are mandatory?
It depends on where you live and what your horse does. The rules usually come from competition, racing and studbook regulations rather than from the law:
- Equine influenza: required for all FEI international competitions and by most national federations and racing authorities.
- EHV-1/EHV-4 (rhinopneumonitis): required in some countries, racing codes and studbooks. In France, for example, it is compulsory for racehorses and some breeding categories (IFCE).
- Tetanus: rarely compulsory, because it does not spread between horses. It is, however, often fatal, so vets treat it as a core vaccine.
Always have the vaccination given by a vet and recorded, signed and dated in the horse's passport.
Why autumn is the right time to review vaccines
- Mares covered in spring reach their 5th to 7th month of pregnancy, when EHV doses are due.
- Competition horses head into the winter indoor season, so flu boosters must be valid without falling too close to an event.
- Horses spend more time stabled and in closer contact, which helps respiratory viruses spread.
Equine flu: which booster before winter?
| Step | Timing | Can the horse compete? |
|---|---|---|
| Primary course V1 + V2 | V2 given 21–60 days after V1 | Yes, from 7 days after V2 |
| First booster V3 | Within 6 months + 21 days of V2 | Yes, but not within 7 days of arrival |
| Later boosters | At least once a year | Only if the last booster is less than 6 months + 21 days old |
Source: FEI Equine Vaccination Requirements. Since February 2025, every flu vaccination of an FEI horse must also be recorded in the FEI HorseApp, in addition to the passport (Equestrian Canada).
National competitions often accept annual boosters instead. Check your own federation's rule book.
Tip: if your horse competes internationally in spring, time the autumn booster so that it still covers the first events of the new season.
In-foal mares: the EHV schedule
EHV-1 can cause abortion, usually in the last four months of pregnancy. Vaccines licensed for pregnant mares are given once in the 5th, 7th and 9th month of gestation (Duvaxyn EHV 1,4 SPC; MSD Veterinary Manual). On farms with a recent history of EHV abortion, vets may start as early as the 3rd month.
| Covered in | 5th month | 7th month | 9th month |
|---|---|---|---|
| March | July | September | November |
| April | August | October | December |
| May | September | November | January |
| June | October | December | February |
The MSD Veterinary Manual also advises giving annual boosters such as flu and tetanus 4 to 6 weeks before the expected foaling date. The mare then passes antibodies to the foal through colostrum, which the foal must drink within its first 24 hours.
Tetanus: the vaccine never to skip
Tetanus bacteria live in soil. A small cut in the field, a nail in the hoof or a scrape in the stable is enough. Every horse is at risk, including those that never leave home. Booster intervals depend on the product, so follow the label and your vet's advice, and check the last tetanus date during the autumn visit.
This year's foals: when to start?
Foals are first protected by antibodies from colostrum. Depending on the vaccine, the primary course usually starts at around 5 to 6 months (Duvaxyn EHV 1,4 SPC), which means autumn for spring-born foals. If the dam was not vaccinated or the foal drank little colostrum, your vet may start earlier.
After the vaccine: simple precautions
- Avoid stress such as travel or hard work just before and after the injection.
- Mild swelling at the injection site or a short-lived temperature can occur and usually settle within a few days. Call your vet if they persist or worsen.
- Under FEI rules, no competing within 7 days of a flu vaccine.
- Make sure every line in the passport is signed and dated by the vet.
Autumn vaccination checklist
- Last flu booster for each horse, compared with the rules that apply to it
- List of in-foal mares with covering dates and months 5, 7 and 9 calculated
- Last tetanus booster date
- Primary course planned for this year's foals
- One vet visit booked for the whole yard
- Pre-foaling flu and tetanus boosters planned 4–6 weeks before due dates
How to keep track without missing a date
With several horses, deadlines pile up quickly: one horse's flu booster, another mare's 7th month, a foal's first dose. In EquiFarmX, the Health module records every vaccination and alerts you before it is due, and the Breeding module works out gestation milestones from the covering date. You can also invite your vet through a dedicated portal.
Frequently asked questions
Which horse vaccines are mandatory?
It depends on the country and on what the horse does. Equine influenza is required for FEI competitions and by most national federations and racing authorities. Some countries, racing codes or studbooks also require EHV (rhinopneumonitis). Tetanus is rarely compulsory but vets consider it essential.
Can you vaccinate a pregnant mare?
Yes, with vaccines licensed for pregnant mares. Against EHV-1 abortion, the standard schedule is one dose in the 5th, 7th and 9th month of gestation. Flu and tetanus boosters are often given 4 to 6 weeks before foaling so antibodies pass to the foal through colostrum.
How soon after a flu vaccine can a horse compete?
Under FEI rules, a horse cannot compete if it received a flu vaccination within 7 days of arriving at the event venue. National rules may differ.
Does a horse that never leaves home need vaccines?
Tetanus protection matters for every horse because the bacteria live in soil. For flu and EHV, the risk depends on contact with other horses; decide with your vet.
What if my horse's flu booster is overdue?
Past the deadline set by the rules, the horse may need to restart a full primary course before competing. Call your vet with the passport as soon as possible.
Sources
- FEI — Equine Vaccination Requirements
- Equestrian Canada — FEI HorseApp vaccination module
- MSD Veterinary Manual — Vaccination in Breeding Horses
- Colorado State University — Vaccination schedule for pregnant mares
- Duvaxyn EHV 1,4 — Summary of Product Characteristics (French)
- IFCE — Vaccination rules in France (French)