Projections of the grazing activity energy cost are based on factors thought to influence or be related to this loss of energy, and are ones that may be fairly easy to estimate in the field. However, inadequate data were available to evaluate this system. Nonetheless, perhaps they may have some utility to account for the considerable use of energy in some grazing conditions until further experimentation is conducted. For simplicity, the grazing activity energy cost is expressed relative to the maintenance energy requirement. Therefore, these values are multiplied by the maintenance ME requirement and added to it, or the grazing activity energy cost plus 1 can be multiplied by the ME requirement for maintenance in a confinement setting.
The source for this calculation method is:
Sahlu, T., A. L. Goetsch, J. Luo, I. V. Nsahlai, J. E. Moore, M. L. Galyean, F. N. Owens, C. L. Ferrell, and Z. B. Johnson. 2004. Nutrient requirements of goats: developed equations, other considerations and future research to improve them. Small Ruminant Research 53:191-219.