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Conditions Of The Foal

This article aims to cover the most common reasons why a young foal might need veterinary attention.


Diarrhoea is a common condition in foals. Up to 80% of foals will suffer from diarrhoea in the first 6 months of life. Most cases are mild but some are potentially life threatening. Infectious causes must be differentiated from sporadic non-infectious causes such as so called “foal heat” diarrhoea. A lot of foals will have an episode of diarrhoea lasting 1-5 days. This is associated with the development of normal intestinal function and this commonly occurs at the same time as the mare’s foal heat (9-10 days post foaling). If the foal is bright and lively and sucking well then there is little cause for concern and the only treatment required is usually just symptomatic (pro-biotics, kaolin etc). Infectious causes of diarrhoea include bacterial (E. Coli or Salmonella) and viral pathogens. Parasitic causes are most commonly seen in the slightly older – from 4 weeks – foal. Veterinary attention should be sought for any foal where the diarrhoea is severe or if there is any alteration in the demeanour (less lively, sucking less frequently, sleeping more) because physiological changes within the foal develop rapidly resulting in dehydration and electrolyte disturbances, especially in warm weather. A dehydration of 15% or more heralds disaster in a young foal unless it receives immediate attention and this can develop within a matter of hours (I have seen two cases in the last week that have required intravenous fluid replacement therapy due to a combination of diarrhoea and sun).


Acute abdominal pain is a common problem in foals. There are many causes, but the outward signs (colic) can be similar for most of these. Abdominal pain is always significant in neonatal foals and veterinary advice / attention should be sought immediately for any foals displaying signs of colic. Foals are more demonstrative of pain than adult horses, and the degree of distress does not always correlate very well with the severity of the condition. Colic foals do not always behave like adult horses with colic; mild cases are usually depressed and anorexic and often lie on their backs in bizarre positions. Tooth grinding is commonly seen with gastro-duodenal ulceration syndromes, foals with bladder problems often present with a dipped back and straining, meconium impaction tends to be seen as an arched back with straining. Severe signs such as rolling and kicking at the belly may indicate a displacement or torsion of the bowel.

Gastric Ulceration

Gastric ulceration is a significant problem in foals and in particular those with prolonged diarrhoea. It is also associated with stress and anti-inflammatory medications (given to foal OR mare). Signs include depression, reduced sucking, tooth grinding, excess salivation, post-prandial colic, weight loss, failure to thrive and diarrhoea. I now put all sick foals or those with prolonged diarrhoea on anti-ulcer medication.

Limb Deformities

The bulk of limb deformities are either flexoral or angular. Flexoral deformities are where the tendons running down the back of the leg are too short for the length of the long bones resulting in a contracted / flexed / over-at-the-knee appearance. Angular limb deformities are where the leg deviates to the outside or inside rather than being straight. The majority of limb deformities are mild and require little more treatment than corrective farriery and management alterations (usually restricted exercise). Both types of deformity are most commonly seen in the larger, faster-growing breeds and so restriction of growth rate by manipulation of the mare’s diet and reducing the foal’s exercise is often required. Severe flexoral deformities (contracted tendons) can be treated early on by the administration of a particular antibiotic which alters calcium binding in the tendon unit and therefore relaxes it. Splinting and / or toe extensions may be required in some cases and extremely contracted tendons may need surgery to cut the check ligament. Severe angular deformities may require more intensive veterinary intervention, recently “shock wave” treatment has become more commonplace, this has the advantage that it can be performed in the stable and is relatively stress-free. Surgical intervention to either speed up or slow down the growth on a particular side of the limb is occasionally used.


Foals presenting with a sudden severe lameness between 1 and 3 weeks of age should be examined very carefully for a septic arthritis which is where bacteria in the bloodstream settle in one or more joints. This condition requires prompt and aggressive treatment if the future health and soundness of the joint is to be preserved. Foals that received insufficient colostral antibodies are particularly at risk of this condition. Other causes of lameness in young foals are usually traumatic (injuries). Developmental orthopaedic disease (OCD) can develop in the older foal – 3 months plus. The lameness see with OCD is usually milder and most commonly seen in the larger faster growing breeds.

Routine Husbandry & Weaning

Foot trimming must not be overlooked in the young foal. Growing foals can develop angular limb deformities very rapidly should the feet grow out of balance. I advise all my clients to get the first foot trim / farrier assessment at 4 weeks of age and monthly hereafter. Patient and sympathetic handling for foot trimming and other procedures at this stage in a horse’s life sets them up well for the future.

Vaccination generally commences at 5-6 months of age with influenza and tetanus. Passports and microchipping should be done before 6 months.

Worm control is one of the most important aspects of stud management, we advise routine worming / egg counts begin at 4 weeks old.

How to wean a foal is the question I am most frequently asked by clients. Weaning is a hugely important part of a horse’s life and doing it wrong causes monumental stress with subsequent issues such as gastric ulceration and behavioural problems. The singularly most important thing to have in place when weaning a foal is that it must be bonded to another horse before it is separated from its dam. At home we wean by simply leading the mare out of the field leaving the foal with the rest of its familiar herd. Basic common sense safety precautions such as sound fencing are obviously vital but under no circumstances should a foal be weaned into a stable on its own or before 5 months of age unless exceptional health concerns for the mare or foal require early weaning. Concerns over the physical safety of a foal jumping out of a paddock / box all too often lead to the inhumane and nonsensical practice of leaving a newly weaned foal alone and in an unfamiliar place. We have found that stress when already bonded to at least one other horse is minimal; indeed many of our foals seem barely to notice that they have been weaned! If you do not have the luxury of a “herd” situation then many of the studs take mares and foals for weaning.

Richard Stringer BVSc MRCVS of Stringer Equine Veterinary Practice