From the Editors of EQUUS
Beet pulp contains lots of fermentable fiber and is fairly easy for horses to digest. It is often incorporated into "complete" or "high fiber" commercial concentrates as a source of fiber and some horse owners feed it as a separate "mash" for a variety of reasons, one of the most common being the belief that it is high calorie and will help horses gain weight.
However, beet pulp is not high calorie--it has only slightly more calories than good quality hay and less than an equivalent weight of oats. Beet pulp does contain about 10 percent protein, 0.8 percent calcium and 0.5 percent phosphorus, making it a more "balanced" source of energy and fiber than the more traditional wheat bran (15 percent protein, 0.06 percent calcium, 1.3 percent phosphorus). The high fiber content may "normalize" fermentation in the large colons, resulting in more efficient "digestion" over all, which may be why many "hard keeper" horses that have a significant portion of their grain concentrates replaced with beet pulp seem to maintain better body condition. It has been used to replace over 50% of the forage in horse's rations without adverse effects when fed with other balanced concentrates.
Be aware however that it has no Vitamin A and that if it is used to replace most of the forage in a ration, Vitamin A may need to be supplemented. Contrary to popular belief, beet pulp itself is not high in sugar. However some beet pulp products DO have added molasses to increase palatability, so owners with carbohydrate intolerant horses need to read the labels carefully. The improved palatability increases the rate of eating, which theoretically could raise the chance of choke. An enduring concern about beet pulp is that if you feed it to a horse dry, it will swell up after it is eaten and cause choke or colic. While some horses have choked after being fed shredded beet pulp, a fairly large university study did not document this problem. A horse can choke on any feed, given the right circumstances. For instance, if the horse is a greedy eater who bolts its food, has poor teeth, esophageal and/or swallowing problems, or lacks sufficient water to drink, he/she may be at increased risk. You can reduce the risk of a horse choking on any sort of feed--especially pelleted or cubed products--by soaking them in water prior to feeding. This is also a good way to encourage increased water intake, especially in the winter. Pelleted, extruded or shredded beet pulp product need to be soaked for old horses and/or those with severe dental problems.