I use food grade oatmeal as a base. It has been scientifically proven that oats are very healthy for horses. A study showed that the NDF (Neutral Detergent Fiber) in oats is very low. Another study also shows that, unlike many other feeds, oat flakes contain very little dust and therefore do not irritate the respiratory tract. The digestibility of oat flakes is very high at 99.7% in contrast to whole oat grains at only 70%.