Liquid Feeds and Sugars in Diets for Dairy Cattle

Sugars are rapidly and extensively fermented in the rumen. Clearly, adding sugar to a diet already high in ruminally degraded carbohydrates should offer little benefit and could decrease digestibility of fiber, whereas diets that have less-than-optimal rumen degraded carbohydrate probably will benefit the most from addition of sugars. Therefore, dietary situations influence the optimum feeding rate of between 2.5 and 5% supplemental sugar (Broderick and Radloff, 2004; Firkins et al., 2008b). The typical inference is of a double-edged sword in that sugars provide a burst of energy to “jump start” ruminal processes, but excess sugar intake could cause a burst of acid production that promotes acidosis. However, current research complicates these traditional interpretations and adds a different dimension to consider.