Metabolizable Protein (MP) Intake Based on Estimates of Ruminally Undegraded Protein (UIP) and Microbial Protein Synthesis
To use this method, characteristics of CP in the diet or individual feedstuffs in the diet are needed. Values for feedstuffs used by Luo et al. (2004a,b) and Nsahlai et al. (2004) are shown below. The dietary proportions are then used to determine average dietary values for these different characteristics. Other required inputs are dry matter (DM) intake, dietary concentrations of forage and concentrate, ME concentrations in forage and concentrate, and body weight (BW). The calculator is set up for input of the average concentrations in concentrate and forage. If mixtures of feedstuffs are used, the proportions of individual feedstuffs will need to be considered to derive average concentratins to be entered below. For mixtures with a large number of different ingredients, use of a spreadsheet might be a consideration. The calculator is set up so that more than one concentrate and more than one forage can be selected, with composition values being entered into the table below. However, this calculator is fitted with a pop-up window entitled "Input Selected Feed Ingredients Percentages to Determine Concentrate and Forage Values". After selecting feed ingredients, click on this button and enter the dietary levels of the various feedstuffs, then click on the "Calculate" button in the pop-up window and average concentrate and forage values will appear in the table below.
ExampleLet's assume the following:
Body weight = 40 kg
DM intake = 1 kg
Concentrate = sorghum grain CP degradation characteristics, with a ME concentration of 12.38 MJ/kg DM, at 50% of the diet
Forage = bermudagrass hay CP degradation characteristics, with a ME concentration of 7.41 MJ/kg DM, at 50% of the diet
Sources used in this calculation method are:
Luo, J., A. L. Goetsch, I. V. Nsahlai, T. Sahlu, C. L. Ferrell, F. N. Owens, M. L. Galyean, J. E. Moore, and Z. B. Johnson. 2004. Metabolizable protein requirements for maintenance and gain of growing goats. Small Ruminant Research 53:309-326.
Nsahlai, I. V., A. L. Goetsch, J. Luo, Z. B. Johnson, J. E. Moore, T. Sahlu, C. L. Ferrell, M. L. Galyean, and F. N. Owens. 2004. Metabolizable protein requirements of lactating goats. Small Rum. Res. 53:327-337.
NRC. 1996. Nutrient Requirements of Beef Cattle (7th Revised Edn.) National Academy Press, Washington, DC.