The type fed to horses is wheat bran, oat bran generally being reserved for human consumption. It is a milling by-product comprising the outer part of the seed coat, which is the first part removed by milling, before the more nutrient rich pollard layer is reached. Bran has an average protein content of about 17% with 24% starch and 7% sugars. Despite its reputation for high fibre, the crude fibre content of bran is quite low at around 10%.
Bran’s big drawback as a feed for horses is its very adverse Calcium: Phosphorous balance. The Phosphorous content is nine times the Calcium level, so even a relatively small amount of bran can have a significantly negative impact on the overall Ca: P ratio in the diet. When used regularly some additional Calcium should be included to balance the high Phosphorous input. Because of its low fibre content Bran is not actually laxative despite its age- old use for that purpose. It is however highly palatable and enjoyed by horses.