Prevention is ultimately better than cure and inoculation can provide horses with immunity against commonly occurring debilitating infections. The principle of all vaccinations is to initiate a course of injections followed by ‘booster’ doses at various intervals, depending on the type of vaccine and the immunity provided.
Is your horse protected?
It is advisable to vaccinate all horses and ponies against commonly occurring diseases, such as TETANUS & INFLUENZA. The horse is the most susceptible of all domestic animals to TETANUS. The causal organism (the bacterium Clostridium tetani) is commonly found in the soil and may be present in horses’ faeces. It usually enters the body via wounds, especially deep and penetrating wounds such as those caused by sharp objects penetrating the sole of the hoof. Deep puncture wounds provide an ideal site for infection. The TETANUS organism only thrives in an environment deprived of oxygen which is characteristic of this type of wound. You must call your veterinary surgeon immediately if your horse has a deep penetrating wound. The vet may administer either tetanus antitoxin or a booster dose of vaccine, depending on when your horse was last vaccinated. Only rarely will veterinary treatment save an animal, once signs of infection become apparent, but immediate veterinary attention is essential. The usual incubation period for tetanus is one to three weeks, the first signs being progressive stiffness and a reluctance to move. Muscles in the region of the wound or hind limbs are normally first to be affected. Spasms of the head muscles cause difficulty in chewing (hence the common name,‘lockjaw’), flaring of the nostrils and a classic startled expression. The ears may be erect, the tail held out and the animal’s reflex reactions to sudden movements or noise are heightened, causing more violent, general spasms. The temperature may rise to 43degC (110degF). Regular vaccination of ALL horses and ponies, against TETANUS, is absolutely essential. The mortality rate may be as high as 90%; in the few animals that recover there is a convalescent period of around 6 weeks.
The horse is the most susceptible of all domestic animals to TETANUS
Vaccination is quick, simple and highly effective and the only practical means of long-term protection. Permanent vaccination with tetanus toxoid can be started at any age from three months onwards. The course consists of two primary injections given approximately four weeks apart, followed by a booster vaccination a year later, and thereafter at 2- 5 yearly intervals. In addition to vaccination, good hygiene and management will help in minimising the risk of infection. Regular inspection of hooves and the lower limbs for cuts will assist in spotting potential sites where tetanus may enter. Clearing yards, paddocks and stables of likely causes of injury (especially barbed wire) is important, to reduce the risk of injury, together with routine disinfection of the premises. Pregnant mares are often given a TETANUS booster in the later stages of pregnancy (usually in the eleventh month).This thereby increases the antibodies available in the colostrum (first milk), protecting the foal for approximately six weeks. To supplement this many foals are given a tetanus antitoxin soon after birth providing temporary cover of three to four weeks. A further dose can be given at four weeks.
TETANUS vaccination is often coupled with the INFLUENZA vaccination. Several pharmaceutical companies produce combinations of the influenza and tetanus vaccine.
EQUINE INFLUENZA (‘FLU) is a highly contagious, viral disease of the respiratory tract. The first sign which you are likely to notice is a harsh, dry cough which will last for 2-3 weeks and may well persist much longer. Although you may not detect it, the cough will probably have been preceded by a rise in temperature for 1-3 days from the normal 38∞C (100.5degF) to 41degC (106degF). Initially there will be a clear discharge from the nostrils, which later becomes thick and purulent. Equine ‘FLU’ debilitates a horse or pony, leaving it susceptible to secondary infections. Influenza can develop into bronchitis or bacterial pneumonia. However, even when there are no complications from any secondary infections, the animal will need to be rested for at least 3 weeks and often considerably longer.
Vaccination – rules for competitions
- Each horse MUST have a VALID vaccination certificate, which undeniably relates to that horse, completed, signed and stamped on each line by a veterinary surgeon, who is not the owner of the animal.
- The record must show that the horse has received TWO injections for PRIMARY vaccination against equine influenza given no less than 21 DAYS and no more than
- 92 DAYS apart. (Only these first two injections need to have been given before the horse may compete).
- In addition, a first BOOSTER injection must be given no less than 150 days and no more than 215 days after the second primary injection.
- Subsequently, BOOSTER injections must be given at intervals of not more than 1 year apart, commencing after the first booster injection.
- None of these injections must be given within the preceding 7 days, including the day of competition or entry into the competition stables. An infected horse is itself a source of infection to others and it is important to make every effort to isolate infected animals. The incubation period for the disease is only 1-5 days and, with horses remaining infectious for 6-10 days after the onset of clinical signs, it is easy to see how rapidly equine ‘flu takes hold. It is essential that your veterinary surgeon’s advice is sought, not just at the onset of symptoms but also before restarting exercise.
The only practical way to prevent infection with equine ‘flu viruses is to ask the vet to vaccinate your horse or pony regularly. There are several ‘flu vaccines available.
Different strains and sub-types of influenza viruses occur, the two main types being A/Equi 1 and A/Equi 2.This vaccine covers against the commonly occurring strains of influenza. However, it should be remembered that influenza viruses vary periodically and are subject to a phenomenon known as antigenic drift. Such variations may result in a breakdown in immunity. Vaccination against INFLUENZA is highly effective and is now mandatory for all horses using racecourse premises. The vaccination requirements are strict and tightly enforced. It is also advisable to vaccinate all horses that regularly encounter large groups of unfamiliar horses, for example hunters.
INFLUENZA vaccinations are also compulsory for many competition horses. It is important to note that many associations and show organisers insist on all horses holding current vaccination record cards. (See Rules for Competitions given above) Allowing regular ‘flu booster vaccinations to lapse leaves your horse open to infection which could lead to permanent damage and is a contributory factor to fresh epidemics. It will also incur additional expense for the owner that could be avoided. With the strict rules laid down by the various governing bodies in the horse world, it will be necessary to start a completely new vaccination regime, even if just one booster is missed or is late – even by just one day.Horses are subject to numerous infections that may cause coughing and a nasal discharge. Just as human colds and other infections may be incorrectly diagnosed as ‘flu, equine ‘flu also has its mimics. ‘The cough’ or ‘the virus’ are terms often heard but usually refer to causes other than equine ‘flu. For instance, many respiratory problems in the horse are due to equine herpes viruses and not ‘flu viruses.
Many stud owners will require proof of vaccination before they allow a mare onto the premises. A vaccine is available to help protect against EHV-1 abortion and the Horserace Betting Levy Board’s Code of Practice recommends vaccination of pregnant mares. Seek advice from your veterinary surgeon if you are considering putting a mare in foal. Always contact your veterinary surgeon if your horse shows any signs of infection. Failure to get a definitive diagnosis could leave your horse, and others, at risk of complications. To assist with diagnosis your veterinary surgeon may send swabs or blood samples to a laboratory. Contact your veterinary surgeon for further advice about vaccination, before it’s too late – it’s the responsible thing to do. Modern veterinary science has developed preventive medicine that is effective, considering the investment you have in your animals and their surroundings it is relatively inexpensive.
Codes of practice
The Horserace Betting Levy Board (HBLB) has produced Codes of Practice with the aim of preventing the spread of equine infectious reproductive diseases: Equid Herpesvirus 1 (EHV-1), Equine Viral Arteritis (EVA), Contagious Equine Metritis (CEM) and other equine bacterial venereal diseases. Copies of the Codes are available (on receipt of an A4 S.A.E.), from the HBLB or the BHS Welfare Department.
The British Horse Society
Stoneleigh Deer Park
Warks CV8 2XZ
This information was produced in conjunction with:
The Home Of Rest For Horses
Bucks, HP27 0PP
Article replicated with kind permission from the BHS (British Horse Society) website.