Regular vaccinations ensure that your horse has maximum protection against infectious diseases in the UK that can cause serious, and sometimes fatal, illness.

We strongly recommend that all equines are vaccinated against equine influenza and tetanus. If you wish to compete your horse in equestrian sport, vaccination will be a requirement of the relevant governing body.

Whilst we endeavour to send vaccination reminders by text it is the owner’s responsibility to ensure their horse’s vaccinations remain up to date and comply with the requirements of any governing body.

Equine Influenza

Equine influenza is a highly contagious viral disease of the respiratory system, caused by different strains of the influenza virus. Horses can contract the disease either from direct contact with an infected horse or through contaminated environment/air. It spreads very rapidly as infected horses incubated the virus for only 1-3 days before developing symptoms. 

The disease can quickly deteriorate into life threatening bronchitis or pneumonia and when recovering, horses are often susceptible to secondary infection as they are left in a debilitated state. Naturally we recommend vaccinating horses against this disease.

A typical equine influenza vaccine schedule (from 1st January 2024) is:

  • A primary course of two injections given between 21 and 60 days apart.
  • A first booster injection given between 120 and 180 days after the second primary course injection.
  • Annual boosters thereafter (must be given within 365 days of previous injection). However, following the Equine Influenza outbreak in 2019, many regulatory bodies and competition centres require that horses have 6 monthly boosters, to reduce the risk of transmission at large events.

Vaccinating against flu is highly recommended and is, in fact, mandatory if your horse is going on to any racecourses. The Jockey Club, International Equestrian Federation (FEI), competition bodies (such as BS, BD, BE etc.) and many Show Societies, Riding Clubs and Pony Clubs produce vaccination protocols to follow for equine influenza. These all vary and it is therefore important that you check the requirements for your particular society/body.

Competition rules

If you wish to compete your horse or pony, the society (regulatory body) with whom you compete will state which vaccination protocol you must follow.

  • Each horse must have a valid vaccination certificate which is completed, signed and stamped by a veterinary surgeon.
  • You must be able to show that your horse has had a primary vaccination course against equine influenza as stated above.
  • No vaccination should be given in the seven days leading up to a competition or entry into a competition stables.          


Tetanus is usually fatal and is caused by the soil borne bacterium Clostridium tetani contaminating any wound however small. Because the incubation period is 7-21 days the wound is very often healed by the time symptoms start to show. 

The risk of tetanus is significant and ever present and approximately 90% of unvaccinated horses who contract tetanus don't survive. Those that do survive require intensive veterinary care for at least 6 weeks.

Vaccination against the disease is very effective and is strongly recommended. Tetanus vaccination is commonly combined with influenza vaccination and if you follow the vaccination schedule for the combined vaccination your horse should be protected against tetanus.

When using separate vaccines, the tetanus vaccination schedule is as follows:

  • Primary course two injections 4-6 weeks apart
  • First booster within 12 months of the second primary injection
  • Subsequent boosters only needed every 2 years

We advise that all horses are vaccinated against tetanus even if they do not travel or mix with other horses.

Equine Herpes Virus (EHV)

This is a common virus in the worldwide horse population. The most common strains to infect horses are EHV1 and EHV4. EHV4 is most commonly associated with respiratory disease whilst EHV1 is more commonly associated with neurological disease and abortion.


Abortions generally occur in late gestation at about seven months and pregnant mares don’t always show signs of infection prior to abortion. Following infection, abortion occurs from two weeks to several months later. Foals can become infected whilst still in the mare’s uterus, which can lead to premature birth, birth of weakly foals or foals that initially appear healthy but become progressively weak and lethargic within the first week of life. Ideally pregnant mares should be kept in small groups and kept separate from any other horses that come on to the premises.

Respiratory disease

Respiratory disease due to EHV is most commonly seen in weaned foals and yearlings in the autumn and winter. Following infection with the virus, they may develop a secondary bacterial infection.


Horses that have recovered can become latently infected with the virus; that is, they don’t appear unwell but the virus is still within the body. When the horse becomes stressed the virus can then be reactivated and re-infection can occur.


Vaccinated horses can still become infected with the virus, shedding it in the environment and infecting other horses but the severity and length of disease will be reduced. Horses can be vaccinated from five months of age. The primary course involves two injections four to six weeks apart. Foals with insufficient colostrum intake can be vaccinated with a single dose at three months then again at five months, then four to six weeks after. It is advisable that all animals on a stud farm are vaccinated against EHV, whether they are pregnant or not, although pregnant mares can still abort following vaccination. It is not advisable to vaccinate in the face of an outbreak of EHV on a yard since it can exacerbate clinical disease.

Vaccination of pregnant mares

Pregnant mares that have had the primary course of vaccination should then also be vaccinated in months five, seven and nine of pregnancy. Boosters are required every six months.

In some cases we will recommend vaccinating against other diseases such as EHV and rotavirus. We are happy to advise when these might be required.

Rota Virus

Rota virus causes diarrhoea in young foals and vaccination of pregnant mares during late pregnancy causes increased antibodies to be produced in the mare’s colostrum (first milk). These antibodies provide increased protection to the foal providing it drinks the colostrum.

Rotavirus is a virus that damages the villi in the intestines making it difficult for the intestines to absorb nutrients from food, otherwise known as malabsorption. The damage to the intestinal lining makes the foal unable to digest lactose, a component of the mare’s milk. This causes diarrhoea that pulls water from the foal’s body. Left untreated the foal will become badly dehydrated, a situation that could lead to death. The virus is carried in the manure and if a horse comes in contact with the manure, the virus can easily be ingested.


It is recommended that broodmares (particularly those foaling away at stud) are vaccinated against Rota Virus. Injections are due at 8,9 and 10 months of pregnancy.


Stallions are also vaccinated for EVA. Please discuss this with your vet.

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Call your local clinic to book an appointment:

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Willesley: 01666 880501

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