Colic

The condition described below — colic in horses — can be a critical, life threatening emergency. If your horse is suffering from any of the symptoms described call the hospital immediately (5756 2444) for advice.

The term ‘colic’ means simply pain in the abdomen — a tummy ache basically. However, while a tummy ache in people usually means little more than a couple of hours or days of discomfort, because of the complexities of the equine stomach, in the horse a bellyache is often much more serious, potentially leading to death within 12-48 hours. All horse owners should be constantly vigilant for signs of colic, and contact the hospital immediately if your horse shows symptoms.

There are many causes for the pain of colic, from mild to life-threatening or fatal. It can be very difficult in the early stages to distinguish the mild from the potentially fatal so all cases of abdominal pain should be taken seriously. When colic develops it is vital that we can quickly identify the cause in order to instigate appropriate treatment.

There are many types of colic but the major types include:

Impaction colic is when the intestine becomes blocked by a firm mass of food. Impactions most commonly occur in the large intestine at one of the flexures. This is a fairly common type of colic which can usually relatively easily treated. However, an impaction may also be just the first obvious sign in a more complicated case.

Sometimes gas will build up in the intestine, most commonly in the large intestine and/or caecum, causing gas colic. The gas stretches the intestine, leading to pain. Gas colics usually resolve fairly easily with appropriate treatment, although, again, it is important to ensure that there is no underlying reason for the problem.

Some cases of colic are due to increased intestinal contractions, the abnormal spasms causing the intestines to contract painfully. Known as spasmodic colic these cases usually respond well to treatment.

Displacement/volvulus/torsion colic, or ‘twisted gut’ colic is where a portion of the intestine has moved to an abnormal position in the abdomen. An incidence of ‘volvulvus’ or ‘torsion’ colic occurs when a piece of the intestine twists. The suspension of the small intestine from the mesentery and the fact that the anatomy of the horse is such that much of the large intestine is not fixed predisposes horses to intestinal displacements and torsions.

Except in rare cases these types of colic cause a total blockage of the intestine and require immediate surgery. In the early stages of a displacement/torsion colic, the signs may be similar to those of a horse showing one of the milder forms of colic. This is why it is vital that horse owners take all cases of colic seriously and seek veterinary advice as early as possible.

Some cases of abdominal pain are due to inflammation of the small (enteritis) or large (colitis) intestines. These are also serious clinical cases and require immediate veterinary attention.

When a horse gorges itself on grain or any feed which expands when dampened, the contents of the stomach can swell, causing a gastric distension/rupture. The horse’s small stomach and its inability to vomit mean that in these circumstances the stomach may burst. Death is inevitable once the stomach bursts. The intake of such feed should be strictly controlled but if you suspect your horse may have overeaten concentrate feeds, seek veterinary advice immediately.

In many cases of colic we can never fully determine the reason for the pain. Symptomatic treatment, close monitoring and attention to any adverse developments usually lead to resolution of the problem.

Clinical signs:

The signs of colic in horses range from almost imperceptible in mild cases to extremely violent in severe cases but the symptoms for any form of colic are the horse indicating it is in pain. The animal may sweat, paw the ground, purse its lips, kick out and perhaps try to bite at its stomach region. They may roll, sometimes assuming unusual positions in doing so. Classically, they may stretch out in a bid to relieve the discomfort. They may also appear drawn up at the flank. The onset is often sudden in colic. In some cases, depending on the cause, their pulse may be rapid, possibly over 100 beats a minute.

Some of the most common signs include:

• Lying down more than usual
• Repeatedly getting up and lying down again
• Standing stretched out
• Standing frequently as if to urinate
• Turning the head towards the flank
• Repeatedly curling the upper lip
• Pawing the ground
• Kicking at the abdomen
• Rolling

What should I do if I suspect colic?

If a horse showing signs of colic is behaving violently call the hospital right away. Violent behaviour usually indicates severe pain, which usually equates with a serious case of colic. Time is of the essence in severe cases. Some horses may become quite violent with a relatively mild case of colic but it is best to err on the side of caution and assume the worst.

If the signs of pain are less extreme you can afford to take a few minutes to observe the horse’s appearance and behaviour before calling us. If you can do so easily, take his temperature, pulse and respiration rates. Note what his appetite has been like in the past day or so, and the consistency and frequency of defecation. Also note the colour of the gums. Ask yourself if the animal’s water intake has been normal in the previous day or two, and if he has had access to any unusual feed, whether any medications have been administered, and whether there have been any changes in management.

Armed with that information, call the hospital for advice. We will almost certainly arrange to come and see the animal unless we are confident it is a very mild case. Before the vet arrives it is important that you remove all food. Try to get the horse to a pen where you can make sure he does not eat.

Walking the horse can help distract him from the pain, but he should not be walked to exhaustion. If the horse insists on rolling, there is little you can do to prevent it. Try to get the horse to an area where he will do himself the least damage when he rolls.

Do not administer any drugs, remedies or ‘DIY treatments’ until we have seen the horse, or we tell you it is safe to do so.

How is colic diagnosed?

Initially we will attempt to identify the cause of the colic, and the stage it is at. An accurate assessment is critical to deciding on the most appropriate treatment. Generally we will check the pulse, temperature, and overall condition of the horse. A lower than normal temperature may indicate that the animal is in shock and in need of rehydration. We will listen for bowel noise, and may perform a rectal examination, and/or pass a stomach tube into the horse.

We are trying to determine if the pain is being caused by an overactive intestine or due to a blockage. The outcome in both these cases is usually positive, provided we are called in quickly enough. If the cause is a twisted bowel, the prognosis is less positive, unless the horse is well enough to undergo urgent abdominal surgery.

Treatment protocols:

Treatment depends on the outcome of our diagnosis and the cause of the colic. Treatment may involve administering oil and a wetting agent via a stomach tube to assist in lubrication. We may also administer a worming agent. Painkillers will almost certainly be given to ease the horse’s discomfort. Depending upon the status of the intestine, we may administer drugs to relax the bowel. Fluids may be given intravenously if the horse is in shock.

Colic caused by a twisting of the bowel is the most serious. Surgery is the only option to save the horse in these cases, provided it is strong enough to withstand an abdominal operation. Without surgery a horse is unlikely to survive beyond 24 hours.

The type and combinations of treatments will very much depend upon our diagnosis and the condition of the animal. The most important thing is early intervention and diagnosis.

How can I prevent colic? 

For a horse, colic is probably an unfortunate fact of life. Good management can reduce the incidence however. Horses which fall into high-risk categories, such as stabled horses in intense training and fit horses recently injured, should be monitored particularly closely.

• Allow as much natural paddock grazing as possible
• Maintain a regular and controlled feeding schedule
• Ensure constant access to clean water
• Provide at least 60% of digestible energy from forage
• Do not feed excessive digestible energy
• Do not feed mouldy hay or grain
• Feed hay and water in preference to grain
• Provide access to forage for as much of the day as possible
• Do not overgraze pastures
• Do not feed horses immediately after work, or give cold water while a horse is still hot following exercise
• Maintain a consistent exercise regime
• Make all changes in diet, exercise level and management slowly
• Control intestinal parasites by worming horses regularly (90 per cent of colic cases are caused in the first instance by parasites — mostly strongyles)

Knowing how your horse eats and digests food can help you understand why there are so many forms of colic. The horse’s gastro-intestinal tract — GIT or ‘guts’ — is similar to that of most species but it has a number of features, some of which predispose it to colic.

Once food has been chewed, it passes down the esophagus, the ‘gullet,’ into the stomach. For such a large animal the horse has a fairly small stomach, holding only 8-15 litres, a design well suited to an animal which, in its natural state, grazes almost continuously. After a period of digestion in the stomach food passes into the small intestine, a part of the gut approximately 22 metres long, with a diameter of 7-10 cm, and a capacity of 40-50 litres. The small intestine looks like a very long sausage running along the bottom of a thin net curtain, with the top of the curtain all bunched together. The majority of the small intestine hangs from a curtain-like membrane called the mesentery, which is attached to one point in the middle of the abdomen, under the spine. This is one of the anatomical features that predispose horses to colic.

At the junction of the small and large intestines the equine GIT has a large blind-ended outpouching over 1 m long and with a capacity of 25-30 litres. This is the caecum — the horse’s version of our appendix and another feature predisposed to causing colic. Food passes from the small intestine into the caecum before passing into the large intestine. Together, the caecum and large intestine form the horse’s ‘fermentation chamber,’ allowing it to gain nutritional support from the complex carbohydrates contained in grasses and other forage. Three to 4 metres long with a diameter of 20-25 cm along most of its length and a capacity of over 50 litres, the large intestine fills a significant part of the abdomen.

The design of this large, unwieldy structure leaves something to be desired, being tethered to the body wall at only two points — at its beginning where it joins the small intestine and caecum, and at its end where it joins the short, narrow small colon which leads to the anus. With only two immobile points, the large intestine lies in the abdomen in a neatly-arranged double-U formation, with one ‘U’ stacked on top of the other. This arrangement entails the food making a journey round a number of 180 bends (known as flexures) in the intestine, another potential cause of colic.