Conclusions
The Digestible Energy (DE) content of most horse feeds can be estimated from a
regression equation developed by KER that uses the crude protein, crude fat, ADF,
hemicellulose (NDF-ADF), non-structural carbohydrate (NSC) and ash content of
feed. This equation works well for most horse feeds except those that contain high
levels of fat or that contain fiber which is either much more or less digestible than
forage. A correction of 0.02 Mcal DE/lb should be applied for every 1% fat over 5%
in a feed. Beet pulp and soy hulls contain highly digestible fiber and their DE contents
are 20-50% higher than suggested by the NRC. Oat hulls have very poorly digestible
fiber and DE values that are only 80% of NRC estimates.
Many manufacturers overestimate the DE content of their feeds. A typical grain
mix without added fat will contain around 1,400-1,450 kcal/lb. A feed with 6% added
fat and a total fat content of around 10% will contain around 1,600 kcal/lb. Feed
manufacturers should review the DE values that they currently use in formulating
horse feeds to insure that reasonable DE values are assigned to their feed ingredients.