If there is anything as fragrant and tempting as a bran mash, redolent with molasses and apples, a horse doesn’t know what it might be. Many an owner has been caught licking the spoon before dishing out that warm concoction to a barn full of horses nickering in anticipation. It’s a scene from a cold winter’s night, almost straight from a Christmas card.

Not only are bran mashes comforting to serve on a bitter evening, they’re also a traditional meal for an ill or convalescing horse, an old-timer with teeth problems, a horse which has a tendency to colic, or a mare which has just foaled. Bran mashes also have been recommended for years as an easy-to-digest, soothing choice for horses undergoing long-distance shipping, and for those which have had an unusually hard workout, such as a long day’s foxhunting. Purported to have a laxative effect, bran often is given to any horse which has been stressed or which might not be drinking enough water. But are all these applications for bran mashes based on fact–or are they just old horseman’s lore?

Bran, What It Is, And What It Isn’t

A byproduct of the milling process, bran is the outer seed coat of a grain kernel that is ordinarily removed. Bran can be made from practically any grain, but the two types most commonly fed to horses are wheat bran and rice bran. (Rice bran, which is relatively high in unsaturated fats, often is used as a fat supplement in the diet of high-performance horses.) For our purposes, we’ll be speaking of wheat bran when we say "bran."

Wheat bran can be milled into fine, broad, or giant-sized flakes; but any way you buy it, it’s a fluffy, low-density feed, only about half as dense as a similar volume of oats, and almost one-quarter as dense as corn or whole wheat. Dry, it has the approximate consistency of sawdust. Bran is relatively high in the B vitamins niacin, thiamin, and riboflavin, but has a poor nutrient content otherwise, with 16-17% crude protein and only 10-12% crude fiber (as compared to 20% for beet pulp or 28-34% for most grass hays). This makes bran a less successful fiber supplement than lore would have us believe, and overall an expensive feed considering the modest nutrition it delivers.

One other significant note about the nutrient content of bran–it has an unusually high phosphorus content, and is low in calcium. This is true of all grains, to one extent or another, but in the case of bran, the imbalance is extreme. Its average crude phosphorus level is 1.27%, and its calcium only 0.14%. Furthermore, 90% of the phosphorus contained in bran is in a phylate form, which can interfere with calcium absorption. Both calcium and phosphorus are important for the growth and repair of bones, teeth, tendons, and muscles, and the horse’s system naturally favors a calcium/phosphorus balance of close to 1:1 (a range of 1.2:1 to 1.6:1 is considered ideal for adult horses, although the exact numbers are less important than the requirement that there always be at least as much calcium as phosphorus). If fed a steady diet high in phosphorus and low in calcium, the horse’s metabolism will attempt to address the imbalance by mobilizing existing calcium from the bones. As minerals are removed, they are replaced with fibrous connective tissue, which increases the size of the bone and decreases its strength. Although the whole skeletal system is affected, in growing horses the effect of such a calcium deficiency is most noticeable in the growth plates of the cervical vertebrae and the legs, resulting in a form of developmental orthopedic disease (DOD). In young, mature horses, it is most obvious as an enlargement of the facial bones–a condition officially labeled osteodystrophia fibrosa, but more commonly known as "big head disease" for obvious reasons. (In older horses, the facial bone enlargement is less obvious.) Before the turn of the century, when work horses often subsisted on a diet heavy in bran, "big head disease" was relatively common (giving rise to one of the other names for the condition: "bran disease").

For this reason, then, a steady diet of bran is not recommended for horses. An occasional bran mash is not harmful, but bran should not be fed to young, growing horses at all, and for adult horses, it should make up no more than 10% of the daily diet.

Can you counteract bran’s calcium/phosphorus imbalance with a supplement? Yes, but it’s best not to mix a calcium supplement (such as limestone) directly into a bran mash. A significant portion of the calcium might become bound to the phylate content of wet bran, and thus unavailable to the horse. It’s best to add such a calcium supplement to the normal grain ration, containing no more than 10% bran, in order to assure a normal uptake of the mineral. (It’s interesting to note that at least one company now has come out with a rice bran product already supplemented with calcium carbonate and ready-to-feed.)

What about bran’s famous laxative effect? Recent studies at Cornell University have unveiled a surprise–whether fed wet or dry, bran has no appreciable effect in softening stools in horses. Even when a bran mash is fed "sloppy," with lots of water, it will not increase the fecal water content by more than 2-3%. Further, bran’s digestibility is not affected by soaking it in warm water. There is no real evidence that bran can help prevent impaction colics, nor that it can help sweep sand through the intestines to prevent sand colic (a major concern of horse owners in sandy locales such as some parts of Florida). The loose manure that many owners can attest to the day after a bran mash is fed now is thought not to be the result of a natural laxative effect, but the consequence of a mild digestive upset caused by a sudden change in the diet. Some researchers feel that feeding bran mashes on an occasional basis may even compromise the populations of beneficial fermentative bacteria in the gut. Thus, feeding bran as part of a stress recovery program actually might be counter-productive–it might be stressing your horse more!

Finally, while serving a warm meal to your horse on a cold winter’s night might make you feel warm and fuzzy yourself, it’s not actually the most effective way to help your horse keep from getting chilled. More internal body heat is generated by the digestion of forage than by any type of grain, including bran. So if you really want to help your horse’s internal thermostat, you should consider increasing the amount of hay he gets during the winter.

So now that we’ve shattered all these illusions, is there any point at all to feeding bran? Well, yes. Bran is an extremely palatable feed, particularly when served wet and warm, so it makes an ideal way to tempt the appetite of a picky eater, an ill or convalescing horse, or a tired mare which has just foaled, as well as a perfect hiding place for bitter oral medications such as bute. And served as an occasional treat (no more than once a week), a bran mash probably does no harm. So in that spirit, we offer the following as a basic bran mash recipe.

Basic Bran Mash

Place approximately one pound of dry bran in a large bucket. Pour boiling water over the bran and stir to moisten. (A metal sweat scraper does an excellent job of this.) You can make the mash "crumbly" or quite sloppy, depending on your and your horse’s taste. Cover the bucket with a large towel, burlap feed sack, or some leg quilts, and let the bran steam for at least fifteen minutes, until its temperature is comfortable to your fingers. Add molasses, sliced carrots and apples, oats, or sweetfeed to taste (if you wish to soften the grains, you can mix them into the bran before adding the water). If adding medications, mix them in just before serving, as any cooking might change their composition and effectiveness. Serve warm to rave reviews. Yield: Serves one to two horses.

Other Options

For those who wish to serve a hot meal, but don’t want to deal with a calcium/phosphorus imbalance or a digestive upset, a simple alternative is to soak dehydrated beet pulp with boiling water (use twice as much water as beet pulp pellets or shreds) and serve warm after one to two hours’ soaking time. Beet pulp is a better fiber source than bran, is low in protein, and is extremely digestible. Its palatability might not be as high as bran’s, however, so consider adding a little molasses if your horse isn’t keen on eating it.

Cooked grains are another traditional way of tempting the appetite of a tired, stressed, sick, or injured horse. Boiled barley, an easily digested meal more popular in the United Kingdom than here in North America, traditionally has been fed to horses after a hard day of foxhunting, to aged horses with dental problems, and to foals in stressful situations. The cooking process softens the small, hard barley grains and helps break down some of the starches, increasing both palatability and digestibility. Furthermore, cooked grains are less likely to ferment during digestion. Be warned, however–cooking can reduce the vitamin content of the grain, and it’s a time-consuming and messy process.

To cook enough barley for one to two horses, put half a gallon of whole barley in a slow cooker, and add water until the level rises above the grain by about two inches. (Don’t use rolled or cracked barley–you’ll end up with a sticky, inedible paste.) Cover and cook the barley for six to eight hours, stirring occasionally. The resulting grain will be moist and soft. Yield: Six to seven pounds (three kg) of cooked barley. This can be fed daily, or just as an occasional treat.

Don’t have six to eight hours? Use the cheater’s method–a hot grain soak. Put your horse’s usual ration of oats or barley in a large tub, and add enough hot water to cover; cover the tub with a towel and let stand for two to three hours, stirring occasionally. The grain will become swollen and soft, though not actually cooked. Add any medications or supplements just before serving.

While none of these warm meals are actually necessary to the horse under most circumstances, few would dispute that they are something most horses enjoy. And let’s face it, many of us enjoy serving them, even if we know we’re really doing it largely to feel that we’re doing something nice for our equine partners. So, next time you’re faced with a cold winter’s night, don’t be afraid to designate yourself the chef for the evening. When your horse comes up for air, the sloppy bran he dribbles appreciatively down the front of your jacket will probably be reward enough.