This form of the disease may have its origin in a variety of causes. Some of these refer to faults or weaknesses in the animal itself; others are connected with feeding and management. In regard to the former, we recognize functional and organic disease of the stomach, bowels, and liver; while in respect of the latter, we notice it to result from sudden changes of environment, excessive labour, want of exercise, irregular feeding and watering, hard water, bad food, imperfect mastication either from greediness or defective teeth, excessive numbers of parasites, the habitual use of artificial foods, and the abuse of drugs.
Loss of condition is in constant evidence in this disease, manifested in leanness, an unthrifty coat, hidebound, and dry skin. The appetite is variable, at one time ravenous and at another indifferent or altogether absent. Licking the walls of the stable, grinding the teeth, an occasional cough, crib-biting or wind-sucking also mark the presence of chronic indigestion. When of long standing, it has been observed that the hoofs become brittle and shelly in consequence of the well-recognized sympathy that exists between the mucous membranes of the digestive canal and the horn-secreting structures of the feet. The excrement emits an unpleasant odour. Constipation is a more frequent symptom than diarrhoea, but a looseness of the bowels is a common accompaniment of the disorder with horses of that particular conformation known as "washy". A distended abdomen, and the occurrence of brief attacks of abdominal pain, are symptoms that sometimes attract the owner's attention, though he may have failed to attach special importance to them.
Before attempting remedial measures, a searching inquiry should be instituted into every detail of the animal's feeding, watering, exercise, and management; the food being examined and the water subjected to the ordinary inspection, and, if need be, analysis. The mouth and teeth should receive special attention, as the whole difficulty may arise out of some disease or disorder in them which renders mastication imperfect. The character of the faeces and urine should be noted, not once or twice, but daily. The former may contain parasites; it may be abnormally pale, indicating impairment of the liver, or it may be coated with mucous, indicating derangement of the bowels. Although after the most exhaustive examination and inquiry the cause may not be discovered, yet the symptoms may be ameliorated by a careful regimen, and assistance afforded by the administration of some of those digestive tonics which experience has proved to be so valuable.
Though the food hitherto supplied to a subject of chronic indigestion may be sound, and in every way suitable to another horse, change to some other forage may be followed by early and marked improvement. In the case of town-kept horses, long strangers to grass, the cause is often an inactive liver, and a turn out at pasture is found to be the best remedy; but a compromise may be effected in most large towns by the employment of green meat, beginning with the first cut of rye-grass in April, and ending with vetches in August, or as soon as the seed-pods become developed.
An animal that has been once the subject of chronic indigestion should never be supplied with oats kiln-dried, or indifferently-harvested or doubt-fid hay; and the so-called "mixtures" which often contain Indian vetches, or "peas" as they are termed by dealers, should not be admitted into the stable.
The want of water has been often proved to be a cause of indigestion, as some horses will only take a very small quantity at a time, and the groom who offers it regularly in a pail does not suspect the fact that a horse is not getting enough. The objections to having water always beside a horse must be made to give way in individual cases, as animals known to be "sippers" will do well if allowed to drink in their own way, i.e. small quantities at frequent intervals, while allowing the bucket to pass them after taking a wholly inadequate quantity.
An occasional aperient is found to be beneficial with some animals, and as a preliminary measure in the constipated, an aloetic or physic-ball may be tried. In animals disposed to distension of the belly a small dose of linseed-oil occasionally is recommended, and salt with the food in regular quantities daily will prove beneficial. Calumba or gentian-root powder, combined with bicarbonate of soda, is also found valuable where flatulence exists and the appetite is indifferent. Iron in its various forms is not advisable in those cases where constipation is a prominent symptom, but it is a valuable adjunct to the vegetable bitters above named for those subjects of chronic indigestion with a tendency to looseness of the bowels. The detection of worms in the excrement will, of course, point to the use of worm medicines before entering upon general treatment intended to combat the condition brought about by their presence. In addition to a suitable diet and medicinal agents, the work or exercise should be made as regular in amount as possible, and its effect noted. If the horse too easily perspires, it may be concluded that he is doing more than is likely to benefit him. Removal of a heavy winter coat will sometimes prove helpful, while clothing and bandaging and plenty of friction to the skin are recommended.