The Utilization of Urea by Ruminants as Influenced by the Presence of Starch in the Ration

Summary 1.Further studies on urea utilization in the rumen fistula heifer are reported. 2.With timothy hay as the sole ingredient of the basal ration, utilization of added urea took place only partially, if at all. In the presence of starch a suitable substrate was provided for the development of an active flora and urea was efficiently utilized. 3.When casein was added to a timothy hay-starch-urea ration the utilization of urea was markedly reduced.