Sources used (discussion and recommendations) for this calculation
method are:
NRC. 2000. Nutrient Requirements of Beef Cattle, Update
2000. National Academy Press, Washington, DC.
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.