Distillers dried grains with solubles (DDGS) are a co-product of distillation that can be added up to levels of 18.2% in the horse's diet. DDGS are defined by the American Association of Feed Control Officials (AAFCO) as “The product obtained after the removal of ethyl alcohol by distillation from the yeast fermentation of a grain or grain mixture.” It is obtained from the removal of ethyl alcohol by distillation from the yeast fermentation of a grain or grain mixture. Due to the processing involved, DDGS contain much lower starch and sugar content then other cereal grains. One of the primary problems with DDGS is that the Ca:P ratio is inverted. The inverted Ca:P ratio, if not corrected, may contribute to bone development problems, particularly in growing horses.