Colic in horses is a term used to describe all types of abdominal pain, rather than a single disease. It can affect horses of all ages and types.
Colic can vary from a mild bout of discomfort that resolves itself, to something more serious that requires medical management, or worst of all a serious abdominal crisis requiring emergency surgery.
Every year hundred of horses lose their lives to colic, with some high profile top competition and racehorses among them.
Most colic cases are successfully cured medically, but 5-10% will require surgery. It is difficult to know which colic case fits into which category, as in the early stages the clinical signs are very similar. Therefore it is vital that a vet is called promptly so they can give expert advice and differentiate whether the problem is medical or surgical as early as possible. The aim is to start appropriate treatment as quickly as possible.
Any colic that requires surgical intervention has a much better chance of success if surgery gets underway quickly.
Signs of colic in horses
The signs of colic vary from case to case, but studies have shown that of horses with colic:
43% paw continuously or intermittently
29% lie down for long periods
21% get up and down
14% repeatedly look at their flank
13% curl their upper lip
10% back into a corner
7% kick at their abdomen
4% stand in a stretched position as if trying to pass urine
Types of colic in horses
There are many different types of colic that horses can suffer from. The list below is not exhaustive, but covers some of the most common examples.
Spasmodic colic: This occurs when the smooth pattern of peristalsis is disrupted, so that gut motility is irregular and it typically presents as periods of acute pain with calmer episodes. It is also known as gas colic, as there may be a build-up of gas in the horse’s gut due to excess fermentation within the intestines or a decreased ability to move gas through it.
It may be caused by a change of diet, a lack of roughage or parasites or other variables from the norm, such as stress, anxiety, transport or unaccustomed hard exercise. The clinical signs are generally mild and respond well to pain relief and spasmolytic medications. Food is normally withheld for a few hours and gradually reintroduced. The prognosis is good.
Impaction colic: A horse kept in a natural environment at grass will graze most of the time, so food passes through the gut at a steady rate. A horse that is stabled and worked will have its diet adjusted accordingly, so that it is no longer a fairly constant trickle feeder. There is an increased risk with a change in management, for example, the hunter brought in after a summer at grass, especially if it is then stabled on edible bedding such as straw. Some such horses will develop a blockage in the intestine, most commonly at the pelvic flexure where the large intestine has a U bend, i.e. the gut contents have to move around a 180 degree turn. The majority of impactions typically respond well to medical treatment in the form of pain relief, fluids and laxatives especially if treated early, but a few cases will require surgery. The prognosis is good, provided there is no underlying cause of the impaction, such as grass sickness.
Sand colic: This colic is most typically seen in horses kept on sandy pastures, especially when there is limited grazing available. The horse ingests sand (and dirt) that accumulates in the gut. It can lead to an impaction or it can irritate the lining of the bowel, causing diarrhoea. The weight and abrasion of the sand or dirt causes the bowel wall to become inflamed and can, in severe cases, lead to peritonitis. Surgery may be required to remove the impacted sand, but the majority of cases will respond to aggressive medical therapy.
Torsion or twisted gut: Various parts of the horse’s gastrointestinal tract have the potential to rotate upon itself, leading to a section of the bowel becoming entrapped and an interruption in blood supply to that section. This in turn causes the section of bowel that has its blood supply cut off to leak bacteria and toxins, resulting in rapid severe fatal toxic shock and potentially gut rupture. A twisted gut is extremely painful for the horse and requires emergency surgery to rectify otherwise it will be fatal.
Diagnosis of colic in horses
If you suspect your horse has colic you should call your vet immediately. While you are waiting for your vet to arrive, the horse should not allowed to eat, although water should not be withheld.
If the horse is only showing relatively mild signs of discomfort, they can be walked gently in hand for up to 10mins to help encourage the natural movement of the gut until the vet arrives. Do not keep the horse walking for longer periods as this will just tire them unnecessarily.
If the horse is trying to lay down and roll, the handler should not try to prevent this. Contrary to popular belief, rolling does not cause a twisted gut, although a twisted gut may make the horse want to roll. Above all be careful when handling a horse with colic. It is best either to put the horse loose in a stable with a deep bed after removing any buckets or other items which could cause injury while the horse is rolling, or lead the horse into an arena with a soft surface with a lunge rein attached to the headcollar. The handler should be wearing a safety hat and gloves.
The vet needs to do a full physical examination, taking into account the clinical signs shown. If a horse is violent, sedation may be required to perform a proper examination, often including an internal or rectal examination of the hindgut. Frequently a sample of peritoneal fluid will be collected as this can provide additional useful information. Abdominal ultrasound is also an important additional technique in evaluation any horse with colic. The vet will also take into account the horse’s history and whether there have been any recent changes to their management before deciding how to proceed.
As the causes and types of colic are so varied, the treatment prescribed by the vet will depend on what clinical signs the horse is showing and the severity of pain and the response to pain relief .
If your horse does not respond with medical treatment at home, then consideration should be given as to whether it is appropriate for the horse to be transported to an equine hospital as promptly as is safely possible to do so. If referral is not an option, and the horse does not respond to further medical treatment, then euthanasia may be required.
The challenging case for both horse owner and vet are the ones that do not fit into either obvious category in that they are not bad enough to justify surgery or euthanasia, but still show recurrent signs of colic of fail to respond well to pain relief. In these case further investigations and probably an admission to hospital may be necessary.
Prognosis after colic
A horse that has suffered a single episode of spasmodic colic or minor impaction is likely to recover fully after treatment and should be able to gradually return to work after a few days to recover. Their day-to-day management going forwards should take into consideration their colic history and avoid any typical risk factors, such as rapid changes in diet including turnout, to avoid future bouts.
A horse that survives colic surgery (about 80% do) will face a recovery period of a few months. Cases where the first few days after surgery go smoothly can return home within five to seven days, while others may require several days of intravenous fluids and intensive medical care, or even repeat surgery.
Once discharged from hospital, colic patients require box rest to allow the abdominal incision to heal, followed by periods of controlled turnout and gradually increased exercise. Most patients can return to gradually increasing work within four to six months. Many horses that have undergone surgical colic have successfully returned to full competitive work.
How to prevent colic
Colic is certainly a case where prevention is far better than cure. While not every case can be prevented, the following should lower the risk.
- Allow free access to forage whenever possible, both in the stable and during turnout
- If the horse needs hard feed, feed little and often. Avoid single large meals
- Choose feeds that low in starch and high in fibre to aid gut health; if extra energy is needed, choose a feed with a higher level of oil
- Do not feed forage or hard feed that is musty or mouldy
- Avoid making sudden changes to your horse’s diet. This includes changes in forage or turnout on to lush grazing
- Have fresh water available to drink at all times
- Ensure your horse’s teeth are checked regularly by an vet or qualified equine dental technician
- Maintain a regular worming programme by performing regular faecal worm egg counts, as recommended by a vet or suitably qualified person.
- Avoid situations where your horse is at risk of ingesting sand
Other risk factors include:
- Stress, including travelling, competing or changes in routine
- Stereotypical behaviours such as wind-sucking and crib-biting
- Long periods of confinement (for example, during box-rest)