Similar to human indigestion, tympanic colic occurs when the intestines become distended with gas.
Causes: The over-production of gas within the intestines, commonly the result of gorging on new grass in the spring. If a horse is turned out onto grass for long periods after being stabled over the winter, it may not be able to digest this quantity of grass and may produce excessive quantities of gas. Likewise, any sudden feed change may induce tympanic colic. Mistakenly providing moldy or spoilt feeds is another common cause. Other causes include improperly or not sufficiently cured hay and grains, lawnmower clippings.
Signs: Gas within the intestines cause stretching of the bowel wall. This is very painful and thus animals often colic violently. Heart and respiratory rates may be as high as 60-70 beats or breaths per minute and guts sounds are often absent since the muscle in the stretched intestinal wall is unable to contract. On rectal examination, balloon-like distension of the intestines may be felt and large amounts of gas may be freed when a tube is passed into the stomach. Peritoneal tap is normal and fecal production is variable, although large amounts of wind may be passed!
Treatment: Liberation of gas from the stomach following ‘tubing’ may cause all pain to subside. Some light exercise such as walking out in hand or lungeing for 10 minutes at the trot may help the animal to ‘pass wind’ and the colic to resolve, however, if the horses (usually young foals) act too violently, it is best to keep them in the stall to prevent injuries to themselves and to people around. Often painkillers (analgesics) and intestinal relaxants may be necessary. (