Equine colic

Meet the number one fatal medical problem in horse

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Bloating (colic) in horse

Bloating, otherwise known as flatulent, tympanitic or wind colic, in horses is an affliction whereby the stomach and bowels become distended with gas. If left untreated, bloating can lead to difficulty breathing, sweating, staggering and ultimately death. Bloating has several possible causes, most of which are related to indigestion in one form or another.

Because of the organs involved in colic, there are many types of causes of colic

A: Stomach

B: Small intestine

C: Cecum

D: Colon

E: Small colon

F: Rectum

General types of colic

Spasmodic colic
Intestinal Parasite
Small intestine colic

The main causes of colic are intestinal distension and reduced blood supply to the intestinal tract. Peristalsis (the waves of contractions along the muscular walls of the intestine that propel the contents along ) of the intestine is reduced and distention will occur due to reduced movement and absorption of water and nutrients. The pressure which results from this lack of passage of material through the digestive system results in a reflex action, which causes adjoining areas to contract in spasm.

Distension and reduced blood flow may be due to an accumulation of gas fluid or feed, digestive disturbances, intestinal obstructions, internal parasites, or twisted intestine (torsion and volvulus). Chronic distension may be caused by a horse constantly swallowing air "wind sucking".

The primary causes of the abdominal pain is the distention of the stomach or intestines, pain is also produced when the peritoneum is stretched during attacks of colic. The first response the body makes to distension is to INCREASE the secretion of digestive juices, which increases the pressure, and causes dehydration and imbalance in the chemical systems of the body. This can often become a feedback reaction which can lead to shock , which must be treated as a separate syndrome by the vet, since it is frequently the cause of colic deaths. The paralysis of the intestine also allows toxic material to escape through the stretched walls and enter the abdominal cavity, where the horse can be poisoned by his own intestinal contents.

Some causes of colic

There are several nutritional aspects of colic which can be managed, thereby reducing the incidence of colic. Digestive colic may result from:

A horse overeating,a horse constantly swallowing air "wind sucking"
A sudden change in diet,
Consumption of moldy feed turnout on the wet pastures of early spring
A heavy meal before work
Feeding or watering before proper cooling after work.

Intestinal obstructions may result from sand impaction, retention of the meconium in foals, foreign bodies, and impactions caused by poor quality hay. Horses kept in sandy environments and fed on the ground or over grazed pastures are prone to consume more sand, predisposing them to sand impactions. Foreign bodies consumed by the horse may provide a nucleus where minerals are deposited until a large foreign body is formed. This foreign body is often referred to as enterolith (intestinal stone). Mature, highly fibrous hay has been implicated in impaction colics. Water deprivation and stagnant warm water may contribute to impactions.

Parasitic load has long been stressed as a potential cause of colic. Internal parasites, especially Strongyles, cause severe damage to the intestinal arteries, reducing or blocking the flow of blood to segment of the intestines. Migration of larvae in the walls of the arteries causes the walls of the vessels to become roughened and scarred. Clots form on the roughened areas and may reduce the size of an important branch of the artery. Ascarids (roundworms) may cause blockage of the small intestine in young horses. Bots in large numbers may cause blockage of the stomach. Therefore, it is recommended that horses be maintained on a regular deworming program tailored to their individual parasite load.

Twisted intestine is a condition in which a portion of the small or large intestine is twisted on itself partially or completely. Twisting may result from rolling or from another cause such as a buildup of gas causing the distended intestine to twist. There is no simple cause effect explanation of colic, because many of the effects on the stomach, small intestine and large intestine are related. For example, blockage or impaction at the junction of the small and large intestines may be due to reduced blood flow because of strongyle larvae migration or due solely to sand impaction.

Colic Etiology (deeply detail)

The etiology of horse colic is divided into two categories, the first being Acute Colic, and secondly, Subacute Colic.

Acute Colic with severe pain might be caused by several situations including the engorgement with grain resulting in acute gastric dilation. Colic in horses can be caused by the impaction, or blockage, of the ileocecal valve due usually to the feeding of finely-chopped indigestible roughage. Colic in horses can occur as a result of intestinal accidents including torsion, bowel strangulation, intussusception and as well through diaphragmatic hernias . Sand colic is often more accurately stated as enteritis . Colic in horses can also occur when there is a haemorahage into the intestinal wall as occurs in purpura haemorrhagica, and the disease known as anthrax . Finally, acute colic in horses can result when a horse experiences a large sudden build up of abdominal gas as a result of eating lush green grass.

Sub-acute Colic includes the two most common forms of this ailment. Impaction of the cecum or colon can occur when the gut attempts to process and pass undigested fiber. A spasmodic colon can occur due to increased gut motility (increased speed of movement in the bowel) following unusual periods of excitement, unusual levels of exercise, and from long cold drinks of water.

It’s important to note that colic in horses can be chronic and recurring, this can result from

blood supply deficiency caused by a verminous aneurysm
adhesions or scar tissue caused by the damage left by parasite larvae
an impaction caused by poor teeth
the consumption of indigestible roughage
overfeeding
old age and the resulting debility that comes with age
and irradical feeding patterns where horses are fed large portions infrequently.

Colic symptoms

**vary according to the severity of the particular conditions. In the horse, abdominal pain is usually sudden. Very few horses exhibit all the signs at one time. Signs associated with mild to moderate pain include

pawing the ground,
sweating
looking around at the belly
restlessness
lack of appetite
stamping the hind feet
lying down.

Stamping the hind legs

looking at the belly

lying down

With more severe, unrelenting pain, horses may:

paw the ground violently
appear drawn up or bloated in the belly
muscle tremors or straining
male horses may stretch out and relax their penis, without urinating
kick violently
sweat profusely
lie down and get up frequently,roll or lie on their backs,sit on haunches like a dog
have an elevated or below normal ( with shock setting in ) temperature
have an increased respiration rate,have an elevated heart rate, or have few or no gut sounds

A horse showing severe signs of colic should be seen by a veterinarian immediately. If the signs of pain are acute and the cause of the distention is not removed, death often occurs within 12 to 48 hours.

Treatment for colic (depends on the colic severity)

The most important decision that has to be made when a veterinary surgeon is managing a horse with colic is whether the horse needs surgical or medical treatment.

Medical Treatment

1. Anelgesia (pain relief)

There are several drugs available to veterinary surgeons to relieve the pain associated with colic. Some have a sedative effect, others are anti-inflammatory. Drugs also vary in their potency and their duration of action. Often veterinary surgeons will use short-acting pain killers so that when the drug wears off, they can evaluate whether the colic episode has resolved or not.

The danger with long-lasting pain relief is that the horse feels more comfortable even though inside its abdomen the intestinal disease is getting progressively worse.

2. Intestinal lubricants and fluids

Primary impactions of the large intestine require lubrication of ingesta to help it pass along the intestinal tract. The lubricant most commonly used in the UK is liquid paraffin (mineral oil in North America). This is administered by stomach tube and, when mixed into an impaction of food material, will soften it and assist its passage.

Another approach to softening impacted food material is to suspend it in fluid within the intestine. This is done by administration of fluids into the stomach via a tube. Most commonly repeated small volumes of fluid are administered, commonly 4-6 litres two or three times per day. An alternative approach is a constant flow of electrolyte solution into the stomach. Both approaches to fluid therapy will result in softening impacted ingesta.

3. Motility Modifiers

The third type of drug often employed in the treatment of colic cases modifies intestinal motility. These drugs may slow down gut motility or increase it. One drug commonly used is effective in the relief of intestinal spasm and returns intestinal motility to normal. The aim of motility modification is to return gut motility to normal.

4. Exercise

Increasingly, veterinary surgeons are using gentle exercise (e.g. walking in hand, gentle lunging) to help in the management of specific types of colic. In particular, this approach can be used to assist the dispersal of gas that has accumulated in the large intestine (tympanic colic), and to help displaced large intestine return to a normal position. However, accurate diagnosis and careful monitoring of treatment is necessary so this approach must only be tried under direct veterinary supervision.

Surgical management (small percentage)

The aims of surgical treatment of colic cases vary according the type of colic in each case. However, in general terms the following therapeutic goals can be achieved at surgery:

Removal of ischaemic (dead) intestine and re-joining of the healthy ends.
Correction of displacement or volvulus of the intestine.
Evacuation of a large intestinal impaction.
Relief of trapped intestine causing a simple obstruction.
Decompression of intestine distended with gas or fluid
.Collection of biopsy samples in order to make a definitive diagnosis
.Characterisation and possible removal of abdominal masses.

Colic management and prevention

Anatomically, horses have developed a specialized digestive system which allows them not only to survive, but also to thrive on high fiber diets . Studies have shown a decreased likelihood of a colic problem if horses are allowed to graze. However lush, high moisture spring pasture can also be a colic risk in horses. Colic problems in horses consuming large amounts of high moisture, low fiber grass virtually disappeared when horses were offered dry hay while grazing these pastures. Therefore, from a colic management standpoint, it is recommended that horses have access to pasture whenever possible, and be provided with additional dry hay when pastures contain a high moisture and a low fiber content (lush spring pasture).

Since horses are anatomically designed to digest fiber, the addition of grain concentrates to the diet is a potential risk factor for colic. Normally, grain concentrates contain large amounts of starch that are absorbed in the small intestine. Starch which is not digested in the small intestine spills into the large intestine where it is fermented by bacteria. One of the end products starch fermentation is lactic acid, which irritates the gut lining and decreases intestinal pH. The increase in acidity causes other more prevalent bacteria to die and release potentially fatal endotoxins. All of these situations can potentially cause the horse to colic.

Using processed grains ( Steam crimping/rolling and grinding or pelleted), limiting the amount of grain provided in a single meal and the use of dietary fat as an energy source to reduce the amount of grain concentrate needed in the diet all will help reduce grain induce colic.Horses confined to stalls have an increased likelihood of colic. First, horses are designed by nature to consume forage in a continuous manner; however, stalled horses are routinely fed their hay and grain in two distinct meals (morning and evening). Second, stalled horses may not be receiving adequate forage to maintain proper gastrointestinal function. This may be especially true for horses being fed alfalfa hay. Alfalfa hay typically contains more calories per pound than grass hay. Therefore, horses fed alfalfa would be provided fewer pounds of hay per day than horses consuming grass hay. Not only are horses fed alfalfa receiving fewer pounds per day, reducing the amount of time spent eating, but alfalfa hay also contains less fermentable fiber than grass hay. The quality of fiber fed can also influence colic potential.

Moldy hay, hay containing blister beetle contamination and hay with low digestibility can contribute to instances of colic. Since horses seem to have an absolute requirement for forage in the diet to prevent colic, it is recommended that a minimum of one pound of dry forage (hay/pasture) per 100 pounds of body weight per day is provided. For horses confined to stalls, the selection of lower calorie hays (grass type) will provide the horse more pounds of hay and mimic the continuous feeding behavior during grazing.

You can keep incidence of colic to a minimum by following sound management practices such as:

supply plenty of fresh, clean drinking water, (The only exception is when a horse is excessively hot. Then it should be given small sips of lukewarm water until it has recover.)
set up a regular parasite control program with the help of your equine practitioner. Utilize fecal testing to determine its effectiveness,
using processed grains ( Steam crimping/rolling and grinding or pelleted),
avoid medications unless they are prescribed by your equine practitioner, especially pain-relief drugs (analgesics), which can cause ulcers,
limiting the amount of grain provided in a single meal , divide daily concentrate rations into two or more feedings rather than one large one to avoid overloading the horse's digestive tract.
avoid feeding excessive grain and energy-dense supplements. (At least half the horse's energy requirements should be supplied through hay or forage. A better guide is that twice as much energy should be supplied from a roughage source than from concentrates.) Hay is best fed free-choice.
make dietary and other management changes as gradually as possible avoid sudden changes in diet,
reduce stress. Horse's experiencing changes in environments or workloads are at a high risk of intestinal dysfunction
feed at regular times and intervals,
feed good quality forages free of mold, weeds and foreign objects, feed a high quality diet comprised primarily of roughage where possible.
check hay, bedding, pasture and environment for potentially toxic substances, such as blister beetles, noxious weeds, and other ingestible foreign matter,
offered dry hay while grazing high moisture pasture,
provide exercise and/or turnout on a daily basis. Change the intensity/duration of an exercise regime gradually.
check the teeth routinely and float file, if necessary,
minimize unnecessary stress, and
know what is abnormal and normal for your horses.