“Colic” is a descriptive term, referring to a group of signs that indicate abdominal pain in the horse. Similar to the term “stomach ache” in humans, colic is a description, not a specific disease.
Most forms of colic arise from dysfunction or obstruction of the gastro-intestinal tract of the horse. However, internal abscesses, kidney disease, and reproductive problems can all cause signs of colic as well.
Gastro-intestinal (digestive) conditions causing colic can be divided into three basic categories:
- Flatulent – “gas colic”
- Hypermotile – diarrhea-related; usually due to intestinal/colonic infection by viruses or bacteria
- Obstructive – obstructive colics can be due to mechanical causes, such as obstruction with feed material or an object such as an enterolith (a stone produced in the gut), or by physiologic causes such as ileus (when the normal intestinal contractions cease) or a torsion (twist) of the gut
Colic symptoms are generally related to the degree of pain and the horse’s ability to tolerate the pain. While some horses will exhibit dramatic signs from even a small degree of gas distension, other horses (especially older ones) may be very stoic, and show only mild signs in spite of having a severe condition.
- Looking at sides and flanks
- Loss of appetite
- Playing in water
- Getting up and down
- Elevated heart rate
- Elevated respiratory rate
- Standing with head down, looking “exhausted”
- Absence of sweating at times when other horses are sweating heavily
A colicking horse may show some of these signs, all of these signs, or none. Signs may change as the course of the condition progresses.
Non-digestive causes of colic symptoms vary and include conditions of malfunctions within the horse such as an entrapped abdominal hernia or an inguinal hernia in a stallion. Stones in the kidney, bladder, urethra or ureters may also produce colic. In a pregnant mare, a twist in the uterus or the positioning of the foal in late pregnancy may cause colic symptoms. In addition, abscesses in the liver or the mesenteric lymph nodes in the abdomen can cause pain leading to colic symptoms.
Causes of colic related to the gastro-intestinal (GI) tract include flatulence (gas) – often related to a change in feed or water intake, stress, or weather, stomach ulcers, diarrhea caused by feed intolerance, bacterial or viral infection or parasites.
In addition, when horses eat off the ground and ingest sand particles, these particles can sink to the bottom on the intestine and cause irritation and/or obstruction resulting in colic.
Especially serious causes of colic include the displacement of a section of intestine that becomes trapped in the wrong part of the abdomen, the twisting or torsion of a section of intestine that twists over on itself, obstruction caused by feed or stones blocking the intestine, or strangulation of a section of intestine that becomes cut off from its blood supply.
Another serious cause of colic is caused by a fatty tumor, called a strangulating lipoma that wraps around the intestine shutting off the blood supply.
These cases of colic are often life-threatening and immediate attention by a veterinarian is often necessary to prevent serious damage to the horse's system or the death of the horse.
Horses are grazers, with relatively small stomachs and long stretches of intestine. This means that they are meant to eat small amounts throughout the day. Many of the digestive causes of colic are related to meal feeding and can be reduced by a slow, consistent feed intake.
Proper parasite control and routine dental maintenance can also decrease incidences of colic.
Horses require large amounts of water to move feed material through their gut. Be sure to provide access to clean, fresh water at all times. Also, adding salt to the diet as the weather changes may keep water intake consistent and help to reduce colic.
Any horse showing signs of colic should be examined by a veterinarian as soon as possible. Because of the number of causes of colic and the varying degree of pain expression by individual horses, owners should not assume that a horse showing mild signs “will just get over it.”
Until the veterinarian arrives, remove access to food, but not water, walk the horse if safe to do so, and do not administer any medications unless specifically told to do so by the veterinarian. Pain killers, such as Bute or Banamine, may produce enough relief to mask some symptoms, making it more difficult for the veterinarian to determine the cause of the colic.
Veterinary treatment may include a physical examination including rectal exam, sedation, passing a tube from the nose into the stomach (nasogastric or NG tube) to relieve pressure upon the stomach, and the use of pain-relieving medications. Veterinarians may also recommend further diagnostic tests such as X-rays, ultrasound, blood work, fecal examination, or an abdominocentesis (belly tap). Because horses are so large, and there are many causes of colic, it may take quite a bit of work to determine the cause.
Once the cause of the colic is determined, the veterinarian will recommend either medical treatment or surgery. Some conditions causing colic (such as torsions, and most enteroliths and displacements) can only be cured by abdominal surgery. Surgeries are usually performed at referral hospitals.
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