Foal Diseases and Syndromes

17th October 2017

There are a wide variety of diseases and illnesses that can affect your foal, however, being vigilant and paying close attention to the daily behaviour of your mare and foal will mean that you identify signs of ill health early so that we can start treatment well before more serious conditions develop.

You should examine your mare and foal at least twice daily for signs of being “off colour”, quiet or lethargic, off their food, colicky or having a temperature.   Monitor your mare's udder; if it looks fuller than normal or if she is running milk this might mean that the foal is “off the suck” and sickening with something.  Often, when foals are unwell they will stand with their head under the mare at the udder but not actually drink.  This can result in them having dried milk on their head from the mare running milk onto them – a tell-tale sign.
Quietly watching your foal for a few minutes will enable you to see its breathing rate, behaviour, alertness and if it is suckling properly.  If you have assistance and are able to, taking the foal's temperature can assist your veterinarian greatly in giving you advice on whether your foal needs an immediate visit or not.

It is not possible to cover in detail all the conditions that foals can get within the scope of this summary, therefore I will look at some of the major clinical syndromes and what signs you should be watching out for.  Ultimately, if in any doubt as to the health of your foal, call the Sussex Equine Hospital to speak to one of our vets for advice.  Early identification and treatment of a problem can often prevent a serious illness developing in your foal.

Prematurity and Dysmaturity

Premature foals are those who have been born between 300 to 320 days gestation (pregnancy duration).  Dysmature foals are those born during the normal gestational range of 320 to 345 days but are showing signs that we would normally associate with prematurity.  Essentially both these conditions involve the same clinical signs that the foal was not “ready for birth” and this could be due to many factors, including hormonal or placental dysfunction in the mare or being a twin foal.

Clinical signs that the foal may show include small body size, having a domed bulging forehead and eyes, weak deformed leg conformation, slowness or inability to stand and a poor suck reflex.  More severely affected foals may show respiratory distress, colic or diarrhoea (due to the gut not being ready to deal with milk) and others may show varying degrees of neurological signs (confusion, poor coordination, inability to suck).  Any foal showing these signs will usually require veterinary attention and advice.  Mildly affected foals are often well managed at home with veterinary guidance by a dedicated and patient owner, however, others will require hospitalisation and a high level of intensive nursing, similar to that which premature human babies require.
Hypoxic Ischaemic Encephalomyelopathy HIE (Perinatal asphyxia syndrome, neonatal maladjustment syndrome, barkers, wanderers, dummies).
These are all different names for the same condition which is thought to be caused by the foal being deprived of oxygen at some stage during the birth process.  This might have occurred because of premature placental separation, a compromised umbilical cord, a difficult or slow birth, dystocia (incorrectly positioned foals), meconium aspiration and caesarean births.  Confusingly, these foals can present in 2 ways; the first being apparently normal at birth (they may have also stood and sucked successfully) but then progressively deteriorate over the following 24 hours.  The other type presents as abnormal immediately from birth, with signs of prematurity, poor coordination, confusion and disinterest or inability to suck.
There is an extreme variation in the severity of the clinical signs foals show with this syndrome and therefore the prognosis for these cases varies enormously and is extremely difficult to predict.  Foals may show neurological signs ranging from mild confusion and poor udder seeking, to seizures, head pressing, blindness and abnormal vocalisation (making barking sounds).  The respiration is often abnormal resulting in poor oxygen supply to the foal's body and brain and the heart rate is usually very rapid.  Foals may also show teeth grinding or mouth chomping that can be mistaken as a suck reflex, but the foal does not swallow and will inhale the milk if attempts to bottle feed are made.  Other organs may also be damaged leading to abnormal intestinal, liver, kidney and bladder function.
These foals almost always require hospitalisation and an extremely high level of intensive care management.  Some will show significant and dramatic improvement over 3 or 4 days, however, others are unable to recover from the multiple organ damage incurred and may end up dying or being put to sleep.


This is the name given to a condition where pathogenic (capable of causing illness) bacteria are present in the foal's bloodstream and it most commonly affects foals less than a week of age.
Septicaemia can be due to many reasons with the major influencing factor being failure of passive transfer (FPT).  The foal relies totally on the antibodies it receives from the mare via the colostrum (the first milk) to fight infection and provide it with immunity.  FPT might occur because the mare has run milk prior to foaling and so the colostrum has been lost, or because the mare did not produce enough good quality colostrum or because the foal did not effectively consume the colostrum soon enough after birth.  Other causes of septicaemia in the foal can be secondary to a placentitis, infection or ill health in the mare, a dirty stable environment or secondary to other syndromes including prematurity/dysmaturity or HIE.
The clinical signs are very similar to other conditions discussed in this section and include fever, depression, “off the suck”, dehydration, respiratory distress, diarrhoea, colic, joint ill/lameness, umbilical infection and neurological signs associated with meningitis (seizures, coma, death).
Like many conditions in the foal, if identified early and treated aggressively they can recover without any long-term consequences.  However, any delay in the diagnosis and treatment can result in a rapid deterioration and the development of more serious life-threatening complications.


It is not normal for new born and very young foals to roll therefore any sign of them rolling should be viewed with concern.  Foals with colic will show similar signs to an adult horse; pawing the ground, rolling, “off the suck” and particular to foals they will often roll to lie on their back with the legs tucked against their chest and the head upside down.
In new born foals the most common cause of colic is a meconium impaction.  The first droppings (meconium) should be passed within 6 hours of foaling; these are usually a very dark green to black colour and very hard.  Other causes of colic in the first few days can be a ruptured bladder, prematurity/dysmaturity, HIE (discussed above) and septicaemia.  Foals can also get colic from eating things they shouldn’t, stomach ulcers, worms, diarrhoea and they may also suffer intestinal displacements and twists that may require surgery.
In young foals, it is easy to think that lameness might have been caused by the mare standing on the foal. This is, however, relatively uncommon and much more serious issues such as an infected joint (septic arthritis) are often the cause.  Septic arthritis is usually due to bacteria in the blood stream infecting the joint.  Left untreated, even if only for 24 to 48 hours, it can rapidly lead to irreparable damage to the joint cartilage and permanent consequences for soundness.  Therefore, if your foal becomes lame it is wise to seek veterinary attention as soon as possible as early identification and treatment of septic arthritis can prevent permanent damage occurring.


Diarrhoea in foals is a very common issue and can vary from being a mild transient problem to being a serious life threatening condition.  “Foal heat” diarrhoea is the name given to scours occurring at about a week of age, usually around the time the mare is having her first season after foaling.  This diarrhoea is actually not caused by the mare being in season but is due to the foal's gut adjusting and establishing the normal gut flora for digestion.  Foals should remain bright, continue to drink well and not have a temperature.  If they show any of these signs then a more serious infectious diarrhoea might be involved.
Foals can get severe diarrhoea caused by bacteria types such as Salmonella, E.coli and Clostridia which are picked up from the environment or from the mare.  There are also viral diarrhoeas, the most common being caused by Rotavirus.  With these more serious conditions, the diarrhoea is very severe, smells strongly and may be projectile and even bloody.  The foals are usually very depressed, “off the suck”, have a fever and might be colicky.

Without treatment, the foals can become severely dehydrated, hypoglycaemic (low blood glucose from not suckling) and also prone to developing other infections (for example septicaemia) due to the compromised state.  Some diarrhoeas we might be able to manage at your home with oral medications, other more serious cases may require hospitalisation for intravenous fluids and intensive care nursing.
Respiratory Conditions
Respiratory disease is a major type of illness in the foal. It can potentially be life threatening and can also hold long term consequences for future performance.  The signs your foal might show are an increased respiratory rate, flared nostrils, exaggerated chest movement when trying to breathe, discharge from the nose, fever, being “off the suck” and coughing (though this is often less common that you would expect).

Respiratory distress at birth can be due to prematurity/dysmaturity, fractured ribs, inhaled (breathed in) foetal fluids or milk or due to HIE (discussed above).  Other respiratory diseases of foals include bacterial infections such as Rhodococcus equi and Streptococcus equi, viral infections such as Equine herpesvirus and Equine influenza and parasitic conditions.  Some of these illnesses will require hospitalisation and intensive care, however, many can be managed at home with appropriate care and medication.