Horses – health

Information about disease prevention and signs of illness in horses.

Administering treatments

Approved activities Category
water 2
topical — backline 3
topical — spray 3
oral — drench 3
oral — intramuscular 3

Horses need to be protected against internal and external parasites, pathogenic and metabolic diseases. The risks will depend on geographic location, stocking rate, frequency of movement and seasonal weather conditions. Treatments and vaccines should be administrated in accordance with directions. Accurate record keeping is important. Disease control and parasite control programs should be developed in consultation with a veterinarian.

Effective disease protection involves undertaking regular preventative measures such as vaccination, worming and monitoring.


The frequency and timing of worming for horses should be determined by the seasons and local weather conditions. Wet conditions will increase the risk of worm problems while dry conditions will reduce the risk of worm build up. It is very important not to under dose a horse when worming as this can increase worm resistance.

Symptoms of a worm burden include weight loss, poor coat, tail rubbing, scouring, anaemia, colic and death.

A feacal egg count (FEC) is a very important tool in worm control. It will determine the degree of worm infestation as well as the type of worm. Results form a FEC will help chose the correct drench, therefore improving effectiveness and reducing resistance.

Worm control in horses

Removing manure from paddocks, yards and stables is important in reducing worm burdens. To assist in breaking the lifecycle of the worm, regular paddock rotation is recommended, as well as having at least one paddock at rest.

New horses or horses with a known worm burden arriving on a property should be wormed and quarantined before joining other horses on the property.

Worming advice


There is no standard vaccination program for horses. Vaccination programs should be designed after considering all risk factors and regulations. Location, amount of travel and amount and type of interactions with the general horse population are all risk factors that need to be considered. Rules about vaccination status of horses may apply to horses participating in competitions, e.g. Equestrian Australia have rules about Hendra virus vaccination for horses competing in NSW. Vaccination against tetanus (Clostridium tetani) and strangles (Streptococcus equi spp equi.) are the most common vaccinations due to the risk posed to all horses.

Foals should be vaccinated at 12 weeks of age, with two follow up boosters spaced two weeks apart (12, 14, 16 weeks). Pregnant mares should be vaccinated 2-4 weeks prior to foaling. Injured horses that are up to date with vaccinations should have a Tetanus toxoid booster, but if they have not been previously vaccinated, Tetanus toxoid and antitoxin should be administered. Other vaccinations such as Equine Influenza, Hendra, Equine Encephalomyelitis, Rabies, Equine Monocytic Ehrlichiosis, Botulism, Equine Viral Arteritis, Equine Rotaviral Diarrhoea and Anthrax are optional and usually only administered if there is an increased risk of disease.

Performance horses should be vaccinated during a spell and not when in full work and stallions should be vaccinated well before the breeding season.

Vaccinations are administered via intramuscular injection by experienced handlers or veterinarians. They should be given into deep muscle like the neck or rump. Some horses become stressed when exposed to injections, so appropriate restraint should be on hand.

Vaccination information

Horse health – vaccination against tetanus and strangles

Using chemicals

Whenever chemicals are used including drenches, vaccines and back-line treatments, care must be taken about the following:

  • Reading all labels
  • Maintaining appropriate storage
  • Adhering to withholding periods
  • Determining the weight of the animals to be treated
  • Determining the correct dose rate
  • Using protective clothing if required
  • Using the correct equipment for application
  • Disposal of chemical containers
  • Documenting the dose, chemical name, batch number, expiry date, withholding period, identity of animal(s) administered to and date of administration.

Signs of Illness

It is important to have good knowledge of the disease status of animals prior to bringing them onto the school farm. This may involve vaccinations, parasite control and even blood tests where applicable. Advice from the local veterinarian or livestock officer should be sought.

It is a good idea to quarantine new horses from existing horses for a period of time. This should allow time for observation of any signs of illness or parasite infestations.

The first sign of illness in a horse may be change of natural demeanour, lethargy or changed eating habits. On closer examination a sick horse may show signs of:

  • Abnormal body temperature
  • Changed gastrointestinal function, e.g. diarrhoea, change in appetite
  • Urogenital function problems such as abortion or infertility
  • Abnormal respiratory function such as coughing, gasping or panting
  • Unusual skin conditions such as lesions and abnormal growths
  • Tucked up appearance, stiff gait, unusual posture, patchy coat, loss of hair
  • Excessive scratching or rubbing
  • Swollen joints or lameness
  • Pawing, increased desire to roll, sweating, looking at the flank, reduced appetite may be symptoms of colic.

Any illness identified and treatments given must be recorded appropriately.


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