Q:What is a vaccine?

A: A vaccine is a weakened or killed pathogen, such as a bacterium or virus (“germ”), or some of the germ’s structure that, when given, stimulates antibody production and protection against the pathogen but is unlikely to cause serious clinical signs. This means that when natural infection does occur, the immune system is able to produce a much faster and stronger response. It is this quick and strong response of a vaccinated animal’s immune system that reduces the risk of the disease from becoming debilitating and spreading to others.

Q:Why should I vaccinate my horse?

A: Vaccination is the best means of protecting horses against potentially fatal diseases such as equine ‘flu’, tetanus, herpes and strangles which can severely affect a horse’s health and performance.

Q:What should my horse be vaccinated against?

A: The most common diseases to vaccinate against are equine ‘flu’ and tetanus, although it is also advisable to protect your horse against strangles and herpes. Your vet will be able to advise you on a vaccination or prevention programme and the frequency of booster vaccinations. If you are concerned about any diseases during breeding, for example herpesvirus or rotavirus, you should also talk to your vet for information on a suitable prevention programme.

Q:What is the earliest age that my horse can be vaccinated?

A: Foals are usually protected during the first few months of life by an immunity passed through the mare’s first milk (colostrum). However, this immunity fades, leaving the foal susceptible to disease within a few months. At this point, vaccination can take over in providing much needed protection. In most instances a vaccination course can be started from six months onwards (four months for strangles vaccine) with a second vaccine given approximately four weeks later. Revaccination frequency will depend on what vaccine is being used, whether the animal is competing and on the level of protection required. In the case of increased infection risk or insufficient colostrum intake, an earlier vaccine can be given at the age of four months followed by the full vaccination programme.

Q:How often should I vaccinate my horse?

A: Booster vaccinations for respiratory disease are required from every three months to fifteen months, depending on the vaccine. Your vet can advise you on this. Booster vaccines for tetanus are required every 2 years.

Q:How effective is vaccination?

A: As in humans, vaccination is never a 100% guarantee since it relies on the ability of each horse to individually mount a satisfactory immune response. As a result, you should never vaccinate a horse that is unhealthy or stressed. A combination of having a complete vaccination programme and enough of the population vaccinated (herd immunity) is how viruses and bacteria are kept at bay. The gold standard is to have a whole yard vaccinated and follow good stable management and hygiene procedures. This will reduce the amount of infective organism in the horse’s environment.

Q:Can I vaccinate my pregnant mare?

■ Flu and Tetanus:
It is advisable to keep your pregnant mare up to date with her flu and tetanus vaccinations so that this immunity can be passed to her foal via the colostrum. Most ‘flu/tetanus’ vaccines are licensed to use in pregnancy. Speak to your Veterinary Practitioner about the most suitable time to booster your mare.

■ Herpes:
To reduce abortion caused by EHV-1 infection pregnant mares should be vaccinated during the 5th, 7th and 9th month of pregnancy.

■ Strangles:
It is not recommended to vaccinate against strangles during pregnancy.

Q:Is vaccination mandatory?

A: It is advisable to vaccinate all horses that regularly encounter large groups of unfamiliar horses, for example hunters and horses that take part in Riding Club and Pony Club activities. Riders or trainers who compete under the International Equestrian Federation (FEI) , Irish Turf Club or British Horseracing Authority (BHA) rules have to ensure their horses’ equine influenza vaccinations are up-to-date to enable them to compete. Most competitions do not permit vaccination within seven days of the event.

The Irish Turf Club/ BHA rules

These rules stipulate that a horse must have two primary vaccinations against ‘flu’ given no less than 21 days apart and no more than 92 days apart. In addition, where sufficient time has elapsed subsequent to the primary vaccinations, the vaccination section of the passport must be completed to show that:

■ A horse has received a booster vaccination given no less than 150 days and no more than 215 days after the second component of the primary vaccination, and

■ A horse has received booster vaccinations at intervals of not more than a year apart or such lesser time as the Stewards of the Jockey Club may, in an emergency, decide

■ Vaccinations have to be administered by a Veterinary Practitioner

FEI rules

Horses competing in FEI competitions require a primary course, in accordance with Irish Turf Club/BHA guidelines, with a first booster (third vaccination) within 7 months of the second vaccination of the primary course. Importantly booster vaccinations should then be given every six months.