Most common diseases in horses

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Undoubtedly one of the animals that has contributed the most to the general development of humanity has been the horse. A good proof of its importance is that veterinary medicine emerged almost exclusively to treat its ailments.

Next, AnimalWised offers you a brief guide to the most common diseases of horses, known since ancient times and, some of them, described in multiple centenary treatises.

You may also be interested in: Most common diseases of dachshunds Index
  1. Equine colic
  2. Tetanus in horses
  3. Equine influenza or flu in horses
  4. Babesiosis or piroplasmosis

Equine colic

Already addressing the corresponding article on the most common diseases in horses, colic is a set of diseases that give rise to a spasmodic pain in the abdomen. Remember that it can be due to multiple causes, and therefore its treatment is different depending on what it obeys, but in general the signs that we will find in a colicky horse they will be:

  • Sweating
  • Nervousness
  • Uncontrolled movements, including self-injury: hitting the flanks with the hind legs...
  • The animal may roll over on itself to relieve pain, which can aggravate the condition.
  • Dehydration
  • Constipation / diarrhea
  • Anti-sallow postures to avoid pain: seated animal if it is a colic whose origin is in a stomach dilation due to accumulation of gases.

Although with the term colic we include too many pathologies to be able to generalize (from impaction of the large intestine due to not being able to eliminate fecal matter, to the presence of foreign bodies in the intestine), there are certain guidelines that can prevent its appearance, whatever the reason for its presentation. For more information, do not miss the article on types of equine colic.

¿What are those guidelines?

  • Feed little by little to the horse, over 16 hours. It is the time these herbivores spend grazing in the wild. A horse that remains in a box and is fed morning and night has a great chance of suffering digestive disorders.
  • Use quality forages, avoiding excess straw, and allowing frequent and spaced access to water. Do not abuse feed and granules.
  • Allow the horse getting light exercise daily, several times, to promote intestinal transit.
  • Install the feeders in an elevated location if the horses are confined.
  • Offer distractions to avoid aerophagia (swallowing air), common in bored horses. In this case we can also see animals with the so-called "bear sickness ", constant swaying, and the "shot ", wearing their teeth against walls or doors.


Given the variety of causes that can cause it, the veterinarian will focus on the specific problem once detected, but until it is located he will proceed to:

  • Ease the pain with spasmolytics (buscopan) and NSAIDs (non-steroidal anti-inflammatory drugs, such as flunixin meglumine).
  • Rehydrate and / or lubricate the gastrointestinal transit with paraffin. May need nasogastric tube.
  • Sedate if the animal is in the self-harm phase.
  • Antibiotics may be required if the problem is a traffic stop and there is excess fermentation of the ingested material, since in this case microorganisms are released into the blood that can cause infections.

Tetanus in horses

It is a common disease in horses caused by Clostridium tetani, an anaerobic bacterium (it works without oxygen) that lives in the soil, especially in the soil rich in organic matter (manure). Horses suffer small cuts or scrapes, for example, head injuries, after stepping on a nail, etc., and through these wounds the bacteria enter the body.

After about 8 days, although it is a highly variable figure, we can see the typical symptom of the disease: involuntary muscle contractions and constants, which are called tetanic due to this disease. In addition, we usually find:

  • Mandibular lockjaw: jaws tightly clenched, unable to open.
  • Muscle hyperextension on the legs, giving rise to a staked horse, without the possibility of flexing them.
  • Expression that is named "sardonic laugh " (although it is more common in dogs): eyes wide open, and retraction of the lip corners.

¿How does Clostridium tetani cause this??

It produces two toxins that have the nervous system as their place of action. The closer the entry point of the bacteria (wound) is to the central nervous system (brain), the more aggressive is the presentation of this disease and the less time it takes to develop.

¿And it has a cure?

If it comes before the toxins paralyze the respiratory muscles (diaphragm / intercostals ...), you will be administered tetanus antitoxin serum and penicillin. You will also be provided supportive therapy, that is, fluid therapy, lower the temperature, sedate if necessary, they may even need mechanical ventilation if there is respiratory paralysis.

¿Horses can be prevented from getting tetanus?

Yes, through the relevant vaccination, with the frequency indicated by the veterinarian. Do not we must let our horse have wounds without disinfecting, so we will have to use hydrogen peroxide in each lesion that we observe to inactivate the responsible bacteria.

Equine influenza or flu in horses

It is the equivalent of equine flu and it is a virus that causes upper respiratory tract disease, but if complications arise, it can affect the casualties (lung, bronchi) causing even death. It is transmitted by air, through sneezing and nasal secretions.

In populations that have contacted him, we can see a mild presentation, with a runny nose, cough, conjunctivitis, and possibly recovery after a few days. This is because if they have previously suffered from the disease, the horses have been partially immunized. However, they can contract it again the following season, especially in cold months, and if the virus invades them when they are sick, poorly fed, or being too young, it can have fatal consequences..

The equine flu symptoms that we usually find are the following:

  • Thick nasal discharge
  • Conjunctivitis
  • Loss of appetite
  • Recurrent high fever (comes and goes)

If it is not treated in time, it can lead to:

  • Pneumonia
  • Chronic obstructive pulmonary disease
  • Bronchitis
  • Even death in case of major complications added to the factors mentioned


If the animal is partially immunized, and the form of presentation is mild, the veterinarian may simply prescribe a mucolytic to thin the mucus, such as bromhexine and keep the horse sheltered and away from other congeners for a few days. Likewise, a quality food to support its immune system helps until the horse is able to repel viral aggression.

If the picture is complicated, it may be necessary to use specific antibiotics of the respiratory system, and support therapies in very debilitated animals.

Remember that mixing horses from different areas without knowing anything about their history can lead to the appearance of an outbreak of equine influenza. If we introduce a partially immunized animal among young horses, we can have an acute outbreak that is difficult to tackle, with high morbidity (rate of animals that fall ill when contacting the virus).


To prevent this common disease in horses, it is necessary to annual vaccination, especially before the cold season, and avoid mixing animals from different sources without knowing their status. There is a vaccine that combines protection against tetanus and influenza.

Babesiosis or piroplasmosis

This is another of the most frequent diseases in horses that also suffer from dogs, cows and other domestic animals, and it is caused by a protozoan, Babesia equi.

Babesia is transmitted by ticks, and their multiplication inside the horse's red blood cells produce all the symptoms of the disease:

  • Anemia (pale mucous membranes, babesias break down red blood cells)
  • Fever
  • Cognac colored urine
  • Anorexy
  • Prostration and sudden death in very acute cases

¿Can be treated?

If we detect the presence of ticks in the horse and / or environment, and we notice our horse strange, the veterinarian will surely opt for the imidocarb injection, in a single intramuscular dose, although sometimes it needs to be repeated after a few hours.

The ideal is to detect babesia in blood through a blood smear, but it is not always possible in the field, since this product can save your life, without losing key hours.

¿We can avoid babesiosis?

The only way to predict this pathology is prevent the horse from getting ticks, which is very complicated. We can apply products weekly on the horse to prevent ticks from getting on it (permethrin type), but they do not last long.

The area where the horse lives (the box) must be disinfected weekly as well, and if the animal is free in the field, it must be avoided that it remains in fern and humid areas, which is almost impossible. There are more problematic areas with Babesia (humid areas and mild temperatures, for example, northern Spain), but it is not exclusive to these places, far from it: it has a worldwide distribution, and causes numerous annual declines in the equine population.

This article is merely informative, at we do not have the power to prescribe veterinary treatments or make any type of diagnosis. We invite you to take your pet to the vet in the event that it presents any type of condition or discomfort.

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