The Animal-Unit and Animal-Unit-Equivalent Concepts in Range Science

Abstract

The terms animal-unit and animal-unit-equivalent have evolved as a means of expressing different kinds and classes of livestock in a common form. This paper discusses the evolution of the concepts, analyzes their conceptual boundaries, and discusses their use in the analysis of range livestock systems. Recent efforts to modify these concepts to develop livestock species substitution ratios for specific ranges are discussed. For greater usefulness in describing range livestock systems, animal-unit-equivalents should be calculated based only on animal-related factors. Also, the animal-unit-equivalent concept should not be redefined in the calculation of pasture-specific substitution ratios.