About 25 years ago, a stabilization process was developed that prevented high-fat rice bran from becoming rancid and preserved its natural properties.
Since then, rice bran has become a darling in equine nutrition, as a lower carbohydrate grain substitute (about 50% the starch level in grains), as a fat source (about 20% fat) and as a supplementary source of soluble fiber, vitamin E and other naturally occurring antioxidants. By adding some calcium, manufacturers correct the drawback of an inverted calcium-to- phosphorus ratio.
All these things are true, but let’s look at them a little more closely:
”Lower” soluble carbohydrate is not low enough for many carb-sensitive horses. At an average 25% sugar and starch, it’s way too high for some.
Lower soluble carbohydrate doesn’t necessarily mean low calorie. Because of the high fat, the calorie level is similar to plain oats. In fact, many rice-bran-based products have fat added on top of the naturally present level, making them weight-gain products.
Stabilized rice bran is a rich natural source of fat, including essential fatty acids, but the balance is heavily in favor of the omega-6 fatty acids, not the omega-3s that are lacking in diets not based on fresh pasture grasses.
Rice bran is something most horses find palatable. It can be a good way to get extra calories into a picky eater or an older horse with trouble chewing hard feeds and hays.
Rice bran can be part of the extra-fat-source for EPSM horses that balk at being fed large amounts of oil, although you have to watch the starch levels in these horses. It can be a good grain substitute for horses that get too hard to handle on grains or get digestive upset but still need a dense source of calories.
Adding a few ounces of rice bran to help make a meal or supplement more palatable is fine. One cup by volume of rice bran is about a pound of feed by weight. You should be able to safely substitute up to one cup rice bran. If you decide you want to feed larger quantities of rice bran, you will need to offset it a bit with beet pulp to balance your major-mineral ratios unless you are using a calcium added product. Check the label. You want the level of calcium in the analysis to be at least 1.2 times higher than the phosphorus.