Net energy (NE) is energy available for maintenance or production after accounting for what?

• A. Nitrogen retention energy
• B. Fecal energy
• C. Urinary energy
• D. Heat increment

Answer: (D)

Net energy is the portion of energy that remains available for maintenance and production after the energy cost of processing nutrients as heat has been subtracted. In the standard energy system, gross energy minus fecal energy gives digestible energy, and subtracting urinary energy yields metabolizable energy. The remaining energy is NE after further subtracting heat increment—the heat produced during digestion, absorption, and metabolism. This heat increment represents the thermogenic cost of using nutrients, and it varies with diet and physiology. Fecal and urinary losses are already accounted for earlier in the energy hierarchy, so NE specifically reflects the energy left after subtracting heat increment.