Colic Often Related to Feed Management

Many people engaged in the production of horses attribute miraculous healing and preventive qualities to feed and/or feeding management. This is all too easy to understand, as the easiest change to make in response to a problem is to change the feed. However, while it is true that much of the overall success of a breeding farm or racing stable can be attributed to accurate feeding programs and sound feed management systems, blaming all problems on nutrition is short-sighted.

It is true that colic, one of the most common health problems affecting horses, can often be related to nutritional mismanagement. Nutritionally induced colic cases can be grouped into two categories: (1) improper forage:grain ratios or inadequate amounts of forage, and (2) the use of tainted feedstuffs.

Far and away the more important of these two is the former. The horse is a wandering herbivore, a continuous grazer with an absolute requirement for long-stem hay or pasture. Failure to realize this simple concept probably results in more colics than any other single cause. If access to hay or pasture is limited, the situation may be made worse if the horses are on a high level of grain intake as well. On high-grain diets, rate of passage of ingesta is increased, allowing more readily fermentable carbohydrate to reach the hindgut. Fermentation of this material can easily result in a decrease in cecal and colonic pH when lactic acid is produced. This decrease in gut pH causes a shift in the microflora of the hindgut, which may result in the release of toxins and subsequent clinical colic. Additionally, in this type of etiology there is frequently an increase in gas production in the hindgut that may lead to colic.

The most effective way to reduce the incidence of colic on the farm or on the racetrack is to feed liberal quantities of good-quality forage, limit grain intake to that necessary to maintain acceptable body condition, and feed the grain portion of the daily ration in small meals and as frequently as is practical. Additionally, it is a good idea to have hay available to mares even in the spring or other times when pasture growth is lush. In many instances, there is simply not enough fiber in young lush growth. There are very few instances when overfeeding dry hay can lead to a problem, but there are numerous problems that can develop if hay is limited.

Besides underfeeding forage, the other important risk factor for colic is feeding tainted or moldy feedstuffs. The horse has a much lower threshold of pain than do cattle, and as such cannot tolerate the gastrointestinal tract insult inflicted by certain molds or the toxins they produce.

It is common in some parts of the world to see large round bales of hay and/or silage fed to horses. Although many times this is done successfully, there is an increased risk of gastric upset when either of these practices is used. Horses generally will not ingest moldy feedstuffs if given a choice, but moldy hay or spoiled silage can be deadly if the horse is forced to eat either because no high-quality alternative is available. Feedstuffs fed to horses should be free of mold and other foreign debris, be of a forage species appropriate for the horse, and be properly cured and stored in a manner that will prevent their contamination.