This condition is usually brought about by external violence acting upon a distended or overloaded bowel, or it may result from overdistension alone. The force with which a horse comes to the ground when suffering a paroxysm of colic is not unlikely to occasion a rent in the diseased gut, and the same may be said of horses thrown for operative purposes while their bowels are loaded with food. If the texture of the intestine is sound it is capable of very great strain without fracture, but in some cases of rupture it has been predisposed by inflammatory softening.
The symptoms of ruptured intestine are not very definite, it being so often a sequel of other disturbances and not the primary cause of illness. When, as sometimes happens after a full belly, a portion of bowel becomes torn during extra or sudden exertion, there are tolerably certain signs of what is the matter. Here the countenance wears the impress of shock, which differs from the mere expression of pain. There is a look of extreme anxiety and depression, cold extremities, rapidly-falling pulse, hurried breathing, cold, patchy sweats, and the other train of symptoms common to abdominal pain. This accident cannot well be confounded with colic of the spasmodic kind, where there are remissions of pain and restoration of pulse during the intervals. In this case the pain is continuous and severe, and the pulse fails to recover any lost power, even though stimulants be given; all that they do is to give temporary support to the action of the heart. An unusual calm or resignation soon comes over the patient, which is unwilling to move, and persistently stands till the powers of life give out and he falls, either to die immediately or after a few fruitless struggles. This cessation from pain following on a bout of colic, when the animal has been very violent, is misleading to the amateur, who will often assure the professional attendant that the patient is better, though an examination of the membranes of the eye, the pulse, temperature, respiration, and handling of the extremities prove the contrary to anyone conversant with horses in health. Sitting on the haunches has been thought by some to be diagnostic of ruptured bowel, but this peculiar attitude may be assumed as the result of pain from other causes. We have said that with rupture generally comes a period of relief from acute pain, but this is by no means constant; on the contrary, all the symptoms may be aggravated, and instead of stupor delirium may follow.
Treatment is of course out of the question, and consideration for the animal's suffering, and the possible danger to attendants and other horses in the same stable, should convince the owner of the necessity of slaughter.