Metabolizability of Dried Distillers Grains Plus Solubles in Finishing Cattle Diets

The feeding value of dried distillers grains plus solubles (DDGS) is a combination of its contributions to protein nutrition as well as caloric intake of cattle. When DDGS is included in diets at levels where dietary CP has been met, the feeding value would primarily be a function of caloric density. A replicated 4 x 4 metabolism study was conducted to measure the caloric value of DDGS at high inclusion levels. Diets were formulated to contain 0, 12, 24, or 36% DDGS. These finishing diets were fed to yearling steers during a 21 d adaptation prior to total fecal and urine outputs collection for 5 d. Increasing dietary DDGS caused increased (P \u3c 0.01) energy density of diets. Organic matter digestibility was not affected (P \u3e 0.15), but NDF digestibility improved (P \u3c 0.01). Apparent N digestibility increased (P \u3c 0.01) with no additional N retention (P \u3e 0.15). Apparent DE increased (P \u3c 0.01) with each incremental increase in DDGS, but metabolizable energy (ME) plateaued at 12% DDGS. The relationship of urine energy: urine N was altered (P \u3c 0.01) by increasing dietary DDGS level. Once dietary CP requirements were met, DDGS had a ME value similar to the corn and SBM mixture it replaced