Two experiments were designed to evaluate the impact of traditional wet distillers grains (T-WDG) compared to wet distillers grains derived from a novel process for conversion of corn kernel fiber into cellulosic ethanol (C-WDG) on nutrient digestibility and animal performance. Experiment 1 utilized 10 wethers in a replicated 5 × 5 Latin square design to evaluate the digestibility of dry matter, fiber, fat, and crude protein in diets containing T-WDG or C-WDG. In experiment 2, 168 crossbred steers were used in a randomized complete block design to determine the impact of T-WDG or C-WDG in finishing diets on performance and carcass characteristics. Although digestibility of T-WDG and C-WDG slightly varied at moderate inclusions in the diet, performance and carcass characteristics of steers fed 30% T-WDG were similar to steers fed 30% C-WDG. Therefore, incorporation of a co-product from a novel, secondary fermentation process for conversion of corn kernel fiber into cellulosic ethanol maintained significant growth performance of cattle when replacing corn in finishing diets.