Integration of human and animal concepts of energy metabolism.

With relatively few limitations, findings derived from the study of the energetics of farm animals provide extremely valuable information in the application of human energetics to the solution of dietary questions. The nature of the body's response to variation in energy intake and the nature of variation among individuals are good examples. It is important to appreciate the differences in the usual experimental constraints of studies with animals and humans. Human requirements are based on the summation of the energy costs of several different activities performed throughout the day whereas animal requirements are based on steady-state conditions at various production levels. Although the factors which influence specific biochemical or physiological events may be very similar, the manner in which those effects are incorporated into energy systems and the terminology used to describe them may differ substantially.