The word ‘colic’ simply refers to pain that originates from within the abdomen but it usually conjures up an image of a horse rolling around in agony prior to requiring death-defying colic surgery.  It is most commonly associated with intestinal disorders but can theoretically be caused by abdominal pain of any origin, and in fact, other disorders such as tying-up are commonly mistaken for colic.  On average in the UK, there is one colic case per ten horses per year and of these colic cases one in ten has serious medical or surgical conditions that must be recognised quickly.

A horse with colic appears restless, dull, dejected and inappetant, often sweating.  It shows all the signs that might be expected given that it essentially has bellyache – looking at its flank, pawing the ground, stretching, lying down and rolling.  The actual source of pain can be caused by excess fluid, food or gas in a specific gut location, intestinal spasm, displacement, entrapment or a twisted loop of gut.  Some colic cases pass very quickly and may simply be related to the fact that horses cannot vomit, however, others can be fatal.

When a horse is showing signs of colic it is essential to first consider its history.  For example, if a horse has just been exercised, it may in fact have tied-up rather than having colic.  Also, it is essential to know if the horse has eaten up, passed any droppings or on any current medication, for example, pain-killers.  If a horse has colic whilst on pain-killers then any pain that it exhibits is actually much more severe than it seems, as the pain has been masked by the drugs it is already receiving.  When assessing a horse with colic it is essential to check its vitals signs – heart/pulse rate, respiratory rate, temperature and mucous membranes.  It is easy to listen to a horse’s gut sounds, which are usually decreased in colic cases except spasmodic colics or swimming colics.  The region of the problem is often identifiable, for example, an area of decreased motility or gas formation can be diagnosed by listening to the gut sounds.  More information is also gained by performing a rectal examination through which it is possible to palpate approximately one third of the abdomen, feeling for distended, painful pieces of gut – perhaps most commonly a pelvic flexure impaction, which is easily identifiable as it rises up into the horse’s pelvis.  Other helpful diagnostic tools include the use of a nasogastric tube to examine the contents of the horse’s stomach, abdominocentesis (using a needle to test for fluid in the horse’s abdomen) and more rarely the use of imaging techniques, for example, ultrasonography.

Colic of any type is a painful condition and thus the mainstay of the initial treatment is to reduce the pain.  However, it is essential not to mask a serious problem and many veterinary surgeons have a general rule that a horse should not receive painkillers twice without either a firm diagnosis, for example, a pelvic flexure impaction, or being at a hospital where the horse can undergo colic surgery should it be necessary.  If a horse has a twisted gut, for example, then the sooner surgery happens, the better – the longer it is delayed, the less chance the horse has of survival.  Other treatments commonly used in horses with colic include sedatives, fluids, electrolytes, antispasmodics such as ‘Buscopan’ for spasmodic colics and lubricants such as liquid paraffin for impactions.

As colic can be caused by any problem in the abdomen that gives the horse pain it is not surprising that there are nearly endless possible causes, however, some are more common than others.  ‘Spasmodic’ colic, whilst probably over diagnosed, is quite common.  Essentially, it is when a horse has an episode of colic and on examination it has obviously increased gut sounds prior to receiving an antispasmodic injection which cures it!  The cause is unknown but the outcome is excellent so nobody seems to care, although worms have been suggested as a possible cause.  The only other common colic that causes increased gut sounds is a swimming colic.  Horses that have just swum start to colic a few minutes after swimming.  Treatment consists of letting the colic pass with or without treatment depending on the severity of the episode.  The cause is not actually known although the shock of a horse going into cold water and ingestion of significant quantities of water (which contains some chemicals) have been suggested as possible reasons with the former possible reason being dismissed on the grounds that horses still have swimming colics in hot countries with hot swimming pools.

The horse can be considered to be poorly designed in many ways and its gastrointestinal system is no exception.  The tortuous passage of the horse’s gut, particularly its large intestine, is verging on the ridiculous and there is one turn of gut that is especially badly designed.  The pelvic flexure refers to a sharp turn of the horse’s colon at the point of the smallest calibre, just as the food is beginning to become more solid due to water reabsorption.  The result of this is that horses commonly get impactions of solid food material here.  Diagnosis of pelvic flexure impaction colic is usually quite simple as such an impaction is quite easily palpable via a rectal examination and a change in diet, exercise or management also seems to predispose a horse to this type of colic.  Treatment involves pain relief and stomach tubing salt in order to draw water into the gut and soften the impacted food, as well as some sort of lubrication, which is usually liquid paraffin, to help the impacted food material pass through the flexure more easily.  The prognosis for affected horses is excellent but it can take several days to clear such an impaction fully.


A horse undergoing colic surgery with an obviously impacted colon

The colics listed above are perhaps the most common types of colic, however, unfortunately there are several types of colic which require surgery.  One type is known as left dorsal displacement of the left colon also known as ‘nephrosplenic entrapment’.  The horse’s colon becomes hooked over the ligament between the kidney and the spleen.  Sometimes the piece of gut can become unhooked with exercise and rolling, but often surgery is necessary to manually correct the entrapment.  Another type of colic which always requires surgery as fast as possible is ‘colonic volvulus’ otherwise known as a twisted gut.  This is a very severe colic which must be operated on immediately if the horse is to have any chance of survival.  The twisted piece of gut essentially poisons the horse and thus the surgeon faces a race against time to remove the affected gut before the horse dies.  





Photographs of a horse undergoing colic surgery for a twisted piece of gut.  The piece of gut that has been twisted has had its blood supply compromised hence the dark colour and this necessitated its removal




Other causes of colic include acute enterocolitis, peritonitis (infection in the abdomen), anterior enteritis, and strangulating small intestinal obstructions that can be caused by tumours, intussusceptions, mesenteric tears, scrotal hernias and intestinal twists.  However, let’s hope that the reader never has to learn about such colics.  One final cause of colic that I would like to cover is gastric ulceration in the horse.  This has become a rather hot topic in the equine press of late, mainly due to our increased awareness and the subsequent frenzy of products available that claim to treat them.  The facts are essentially that ulcers in the equine stomach are common but unless severe their significance is questionable.  Moderate ulceration is often found in normal healthy racehorses that are performing well and skinny, poor-looking racehorses that are running badly often have no ulcers!  Nevertheless, severe gastric ulceration can cause problems such as poor performance, poor body condition and reduced appetite, as well as mild colic.  Diagnosis is carried out by introducing a gastroscope into the horse’s stomach.  There are several treatments available on the market, however, only omeprazole has been proven to be effective in significant scientific trials carried out on horses and it is expensive, which is in stark contrast to the vast number of cheap alternatives available.  Unless the affected horse has very severe gastric ulceration, turning it out in a field is by far the best treatment.




   









Above is a series of photographs showing gastric ulceration in different horses’ stomachs.  The photograph on the left is a relatively normal horse’s stomach with a few small ulcers visible just above the ‘margo plicatus’, which is the junction between the glandular and non-glandular parts of the stomach.  The photographs in the middle and on the right show obvious gastric ulcers

With reference to horses in training at Mark Johnston Racing, we take colic extremely seriously.  Whilst our incidence of colic is nowhere near one in ten, if there is even a possibility that the horse could require surgery for its abdominal discomfort then it is injected only once with painkillers and sedation as necessary and carefully transported to Greenwood Ellis and Partners Veterinary Surgeons at Newmarket, our colic surgeons of choice.  Whilst many colics pass without much event, there are a small minority of cases which should be operated on as soon as possible and it is these cases that make us take any colic case so seriously.