Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/24/2003
Publication Date: 7/1/2003
Citation: JOHNSON, D.E., FERRELL, C.L., JENKINS, T.G. THE HISTORY OF ENERGETIC EFFICIENCY RESEARCH: WHERE HAVE WE BEEN AND WHERE ARE WE GOING?. JOURNAL OF ANIMAL SCIENCE. 2003. v. 81(E. Suppl.1). p. E27-E38.
Interpretive Summary: Historically, little effort has been focused on amount or causes of individual variation in efficiency of utilization by cattle, even though differences between individuals have long been recognized. Observed maintenance requirements and energetic efficiencies, for example have not been substantially altered during the last 100 years of intensive beef production. Reasons for lack of change in energetic efficiencies include lack of a consistent selection goal, loose and inconsistent definition of efficiency, concentration on output characteristics, and emphasis on population similarities rather than individual variation. It is time to assess new or different tools and concepts to enhance efficiency of dietary energy use by beef cattle. Application of older (e.g., residual feed intake) and newer (e.g., Chips, ChIPs, QTLs, microarrays) technologies offer the potential to realize improved maintenance and system energetic efficiency through identification of individual animal phenotypic and genomic uniqueness.
Technical Abstract: Knowledge of energetic efficiency has followed a recognized pattern of evolution beginning with novel insights leading to creative new concepts. The second phase was the integration of concepts from other fields to create new principles applicable to the field. The third phase is the adoptive or dissemination phase yielding solutions to industry or societal problems. It is our contention that animal energetics has been in the adoptive phase for about 100 years. Concepts developed during the early phase of nutritional energetics included the concept that life is a combination process, the laws of thermodynamics and the Law of Hess. Subsequent efforts established relationships between gas exchange and heat production and established the concept that food not only functions as fuel, but as body-building materials. Much of the research effort for the last 100 years has been to: 1) devise basis for evaluation of foods that could be related to energy requirements and energy expenditures and, 2) establish causes of energy expenditures. Much of the effort has focused on biology as general and broadly applicable processes (e.g., mice to elephants) and has been targeted at broad-based populations or species.