Colic refers to the clinical signs or symptoms associated with abdominal pain in horses. Pain usually results from distention of some part of the gastrointestinal (GI) tract due to an obstruction, or an actual anatomic GI tract displacement. The incidence of colic has been estimated to be from 4% to 10% over a horse’s lifetime. Often the specific causes of a bout of colic remain unknown, with many individual painful episodes often being transient and with the horse recovering fully. But any case of colic should be taken seriously, as colic is likely the most common cause of premature death in horses. Careful monitoring of any horse with colic is required to determine whether the cause is more serious, potentially requiring surgery.
Complete intestinal obstructions, or total anatomic displacement of a visceral structure, will require surgical correction. Surgery that is completed on horses earlier in the course of the colic episode, before systemic compromise becomes more severe, results in more favorable overall outcomes. Careful monitoring, and discussion of whether surgery is even an option in a given case, is very important. If surgery is an option, early contact should be made with a surgical facility so appropriate plans can be made. Many cases of equine colic requiring surgery have completely successful recoveries with no long term complications. These numbers are strengthened if the patient arrives at the surgical facility with the least amount of systemic compromise.
Causes and Signs of Colic
Most colic is of unknown cause (idiopathic) and transient in nature. Many idiopathic cases of colic are likely due to a gas accumulation, with or without a temporary impaction or obstruction. It is likely that many of these cases occur with an owner never being aware that they occurred. Clinical signs include frequent lying down and getting back up, looking at the flank, and just a generalized appearance of discomfort. This type of case usually gets better fairly quickly following some light hand walking exercise.
With more severe obstructions or gas accumulations, the clinical signs become more graphic. Frequent lying down and getting back up, and rolling are common. Horses display an overall appearance of distress, and signs of discomfort escalate fairly quickly. If a heart rate or pulse rate can be taken it is usually quite elevated. Although some more severe cases of colic can also be self-limiting, an owner or attendant needs to start thinking about getting veterinary input if 45-60 minutes has passed and the painful signs are either not abating, or increasing in frequency. Sometimes the injection of an analgesic medication at this stage can relieve sufficient intestinal spasm that GI motility can reestablish and the mild obstruction and gas accumulation can dissipate. However a quick return of painful signs after administration of an analgesic is one of the main indicators that surgery may be required.
With complete anatomic obstruction, as in a colonic displacement or what is referred to as a strangulating obstruction, signs of abdominal pain are much more profound, and often the pain is not controlled with analgesics. Such horses need veterinary evaluation, as surgery is the only intervention that will be successful. Heart rates are persistently elevated in these horses, and the observable signs of abdominal pain can often be quite profound. Care must be taken so that attending personnel are not injured while trying to help some of these horses. It is NOT mandatory to try and keep a colicy horse walking, and it is okay to let them lie down and roll if they choose.
If a person has become familiar with the normal appearance of the mucous membranes inside a horse’s mouth, they may notice a change in color in more severely affected horses, accompanied with a slowing of what is referred to as the capillary refill time (CRT). This gives a general assessment of how well the heart and circulatory system is functioning, and whether endotoxemia may be developing. If a veterinarian were present, they would always complete a rectal palpation to try and determine if a major obstruction (impaction) or displacement is present. Again it is important, if surgery is a consideration at all, to make arrangements to get to a surgical facility before the overall systemic status of the patient deteriorates to the point where success becomes less likely.
What Can an Owner do?
Owners should know about proper nutrition and feeding practices so they can minimize the incidence of certain types of colic episodes. These would include impaction type obstructions from poor quality forage feeds or hay, or those resulting when many horses compete for the same supply of hay and the least dominant horses end up eating the hay that is left over. As many horses do not have access to pasture and grazing, feeding good quality hay and having consistent feeding routines can help avoid many intestinal upsets causing colic.
With their veterinarian, owners should discuss what procedures and protocols they should follow in the event they find their horse showing signs of colic. This allows for a plan to be made and followed that can help get the case to resolution whether it ends up being a transient mild case of colic, or one that ultimately requires surgery.