Recently, biofuel processing has produced a large amount of biofuel coproducts. However, to date, there is little information on the metabolic characteristics of proteins and energy in biofuel coproduct-based rations. The objective of this study was to study the metabolic characteristics of proteins and energy in biofuel coproduct-based rations in terms of (1) chemical and nutrient profiles, (2) protein and carbohydrate subfraction associated with various degradation rate, (3) rumen and intestinal degradation and digestion kinetics, and (4) metabolic characteristics of proteins. Two sources of grain corn were mixed with two sources of biofuel coproducts (wheat-based dried distillers grains with solubles, wDDGS) in ratios of 100:0, 75:25, 50:50, and 25:75%. The study revealed that increasing the biofuel coproduct inclusion level increased most of the nutritional components linearly (P < 0.05) except starch, which linearly decreased. With increasing biofuel coproduct inclusion level, the rumen degradation rate and the effective degradability of organic matter were not affected (P > 0.05), but the effective degradability of starch was decreased (P < 0.05). Effective degradation of crude protein and neutral detergent fiber as well as predicted truly absorbed protein supply in the small intestine and degraded protein balance were increased (P < 0.05). In conclusion, the inclusion of the biofuel coproduct up to 25-50% in rations improved potential nitrogen and energy synchronization for microbial growth and improved truly absorbable protein supply to the small intestine, without altering energy value.