Digester tankage containing approximately 60 per cent protein has been recognized for the past two or three decades as a standardized feed, highly efficient for supplementing grain in swine rations. Most of the animal tankages containing less than 60 per cent protein have not been considered standard hog feeds. Feeders have used these lower protein tankages in swine rations, but without very satisfactory feeding recommendations from the agricultural experiment stations. It has been common practice to calculate both feeding value and price of the lower protein tankages on the unit of protein basis with the 60 per cent digester tankage as a standard. Although this practice has been considered inaccurate by experienced feeders and feed experts, experiments with hogs comparing high and low protein tankages were necessary to reveal the grossness of the error in this method of valuing tankages. Recent experiments at the Purdue Agricultural Experiment Station indicate that the unit of weight is more nearly accurate than the unit of protein as a basis for measuring comparative values of tankages fed with corn and legume pasture.