Vaccination is a vital part of horse ownership. As vets we are faced with an increasing number of vaccinations on the market, and as owners you are faced with more choices when it comes to the vaccination of your horses. What follows are some brief reminders as well as some new information.


An essential - unlike other diseases which we vaccinate against, tetanus does not require contact with other horses. In fact, the bacterium (Clostridium tetani) which causes tetanus, lives in the soil - especially where there is a lot of manure. As such, most horses are exposed. The organism gains entry when the skin barrier is breached, most commonly in puncture wounds, but sometimes the point of entry can be more subtle than an obvious wound. I am sure that you are all aware of the classic ‘lock jaw’ appearance of a horse with tetanus and of the limited success and large expense of treatment. We would all like to believe that tetanus is a disease confined to historical vet books, but three horses in our practice have died of tetanus over the past year. It should also be noted that insurance companies do not pay out for the treatment of tetanus because they view it as part of normal management.

VACCINE PROTOCOL: Initial course - 2 injections 21 - 92 days apart, then a booster every 2 years.


Influenza infection results in a cough, fever, nasal discharge, lethargy and unwillingness to eat. Spread occurs through the aerosol produced by coughing individuals. All ages are susceptible to this virus although it is most common in young (2-3 years) unvaccinated horses. Vaccination against ‘flu is often a requirement for entry into livery yards and competitions.

VACCINE PROTOCOL: Initial course - 2 injections 21 - 92 days apart and the third 150 - 210 days later. Booster injections are then given within 365 days (inclusive). Competition horses require to be vacintaed every 6 months.


The herpes virus is responsible for three syndromes in the horse:

  1. Abortion in pregnant mares.

  2. Upper respiratory tract infection

  3. Neurological disease.

The virus is spread via aerosol inhalation i.e. in the air. Protection is available in the form of a vaccination, the timing of which is determined by the syndrome being guarded against. Where the concern is mainly respiratory, there is a vaccination which combines ‘flu and herpes (Equillus Resequin) which is both effective and economic. It has been shown that the maximal protection against herpes abortion has been to vaccinate in mid to late pregnancy.

VACCINE PROTOCOL:  General protection against upper respiratory/neurological syndromes either in the form of herpes only vaccine or Equillus Resequin (Flu and Herpes). Initial course - 2 vaccinations 3 - 6 weeks apart then boosters every 6 months.

Pregnant mares and abortion prevention: Given during pregnancy at 5, 7 and 9 months of gestation.

Mares and Foals

The greatest immunity is passed on to a foal from a mare if she is vaccinated 1-3 months before foaling. Herpes, flu and tetanus are all licensed for use in the pregnant mare. Then the foal can begin the primary course of vaccinations at 5-6 months.

If the mare has not been vaccinated, the mare and foal should receive a tetanus antitoxin injection within 24hrs of foaling . The foal can begin its tetanus vaccine course at 6 weeks of age and its ‘flu course from 3 months.


The material contained in this website is presented for information purposes only . The material is in no way intended to replace professional veterinary care or attention from a professional veterinary surgeon. 

The advice given in any of our web pages cannot be used as the basis for a diagnosis or choice of treatment.

Clyde Vet Group advises that you should always consult a veterinary surgeon about any queries with animals under your care.

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