Metabolizable Protein (MP) Intake Based on Estimates of Ruminally Undegraded Protein (UIP) and Microbial Protein Synthesis

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In the other calculation procedures, a simple method has been used to convert requirements for MP into CP. This method involves the assumption that the conversion varies between 0.64 and 0.8 (i.e., 1 g CP is equivalent to between 0.64 and 0.8 g MP) for diets with CP being 100 to 0% degraded in the rumen. For most practical purposes when the dietary CP level is near the requirement, this should be adequate. However, it is more appropriate to base MP intake on the two major origins of amino acids absorbed in the small intestine (i.e., ruminally undegraded true protein and microbial true protein synthesized in the rumen and flowing to the small intestine). This is probably more important for instances in which diets very high in CP are consumed.

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.

Example

Let'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

1. Enter BW (kg)
2. Enter DM intake (kg)
Concentrate Forage
3. Enter total dietary CP concentration (fraction, e.g., 0.12 or divide % DM by 100)
4. Enter soluble CP (g/g total CP)
5. Enter intact protein slowly degradable in the rumen (g/g total CP)
6. Enter rate of degradation of SDP (/h)
7. Enter acid detergent insoluble CP (g/g total CP)
8. Enter ruminally undegraded but intestinally digestible protein (g/g total CP). Calculated as the difference between total CP and the sum of SolP, SDP and ADIP
9. Enter non-protein CP (g/g SolP)
10. Enter dietary percentages of concentrate and forage (DM basis)
11. Enter ME concentration in concentrate/forage (MJ/kg)
To convert from English to metric system,
enter your values here.
They will be automatically entered into the table to the left.
BW
(lbs)
DM intake
(lbs)

To estimate the dietary ME concentration, often feed tags list the Total Digestible Nutrient (TDN) concentration. Likewise, most commercial feed laboratories estimate the TDN concentration based on various analyses, such as for crude protein and fiber fractions.

The ME concentration can be calculated with these simple formulas:
ME (MJ/kg) = TDN (%) × 0.15104 and
ME (Mcal/kg) = TDN (%) × 0.0361.
Enter TDN (%)
 ME (MJ/kg)
 ME (Mcal/kg)

Our example results in MP intake of 72.2 g or 7.22% of DM intake. Since the UIP concentration is 42.6% based on the formula: conversion of CP to MP = 0.64 + (% UIP × 0.16), the predicted conversion of CP to MP is 0.708, which is very close to the value estimated from this example by dividing MP intake by total CP intake (i.e., 0.706).

Select Feedstuff
(Concentrates and/or Forages)		 Feedstuff CP (g/g DM) SolP (g/g CP)1 SDP (g/g CP)2 kd (/h)3 ADIP (g/g CP)4 DRUDP (g/g CP)5 NPCP (g/g SolP)6 ME (MJ/kg DM)7
Concentrate Ammonium chloride 1.642 1.00 0.00   0.000 0.00 1.00 0
Concentrate Apple pomace 0.063 0.25 0.61 0.035 0.315 0.00 1.00 10.42
Concentrate Barley grain 0.138 0.25 0.70 0.350 0.050 0.00 0.29 12.72
Concentrate Barley grain, rolled 0.124 0.3 0.61 0.23 0.04 0.05 0.29 12.72
Concentrate Blood meal 0.955 0.10 0.61 0.019 0.010 0.28 0.00 10.00
Concentrate Bone meal 0.132 0.18 0.48 0.072 0.000 0.34 0.00 16
Concentrate Brewers spent grain 0.292 0.18 0.65 0.047 0.120 0.05 0.75 10.00
Concentrate Canola meal 0.393 0.18 0.81 0.044 0.064 0 0.65 10.42
Concentrate Casava chips (tapioca) 0.038 0.25 0.70 0.120 0.050 0.00 0.45 14.14
Concentrate Chickpea 0.266 0.12 0.82 0.071 0.010 0.05 0.23 13.50
Concentrate Coconut meal 0.213 0.28 0.65 0.087 0.030 0.04 0.75 11.34
Concentrate Corn grain (ground) 0.094 0.24 0.73 0.049 0.032 0.00 0.73 13.31
Concentrate Corn bran 0.119 0.45 0.49 0.070 0.005 0.06 0.80 12.27
Concentrate Corn gluten meal 0.650 0.04 0.91 0.023 0.046 0.01 0.75 13.47
Concentrate Cottonseed meal 0.449 0.26 0.56 0.068 0.040 0.15 0.40 11.34
Concentrate Dried beet pulp 0.100 0.05 0.91 0.020 0.060 0.00 0.96 12.09
Concentrate Faba bean seed 0.314 0.67 0.33 0.039 0.020 0.00 0.23 13.10
Concentrate Feather meal 0.92 0.23 0.24 0.066 0.32 0.21 0.89 10.29
Concentrate Fish meal 0.685 0.23 0.72 0.014 0.01 0.04 0 11.05
Concentrate Grape skin cake 0.067 0.27 0.62 0.11 0.11 0 0.96 3.71
Concentrate Groundnut cake 0.518 0.62 0.37 0.161 0.021 0.00 0.23 12.46
Concentrate Lupin seed 0.345 0.30 0.67 0.261 0.034 0.00 0.68 11.80
Concentrate Meat meal 0.576 0.35 0.40 0.060 0.032 0.22 0.27 11.34
Concentrate Meat and bone meal 0.542 0.18 0.48 0.072 0.032 0.31 0.27 11.34
Concentrate Molasses 0.085 0.74 0.26 0.032 0.000 0.00 1.00 10.88
Concentrate Mustard oil cake 0.385 0.23 0.70 0.104 0.063 0.00 0.65 11.34
Concentrate Oats 0.132 0.65 0.29 0.174 0.023 0.04 0.19 11.63
Concentrate Palm kernel cake 0.194 0.24 0.7 0.07 0.097 0 0.75 12.09
Concentrate Rice bran 0.155 0.33 0.49 0.050 0.026 0.16 0.80 10.59
Concentrate Sorghum grain 0.116 0.19 0.79 0.055 0.086 0.00 0.33 12.38
Concentrate Soybean hulls 0.141 0.23 0.72 0.062 0.072 0 0.72 12.09
Concentrate Soybean meal 0.499 0.05 0.93 0.037 0.020 0.00 0.55 13.18
Concentrate Soybean meal, formaldehyde treated 0.471 0.07 0.93 0.028 0.000 0.00 0.55 13.18
Concentrate Soybean meal, heat-treated 0.463 0.09 0.91 0.02 0.01 0 0.84 13.18
Concentrate Sunflower meal 0.284 0.42 0.53 0.292 0.049 0 1 10.23
Concentrate Urea 2.880 1.00 0.00   0.000 0.00 1.00 0
Concentrate Vetch bran 0.256 0.56 0.44 0.167 0.010 0.00 0.96 10.59
Concentrate Wheat bran 0.173 0.34 0.63 0.200 0.081 0.00 0.75 10.59
Concentrate Wheat middlings 0.185 0.4 0.54 0.15 0.03 0.03 0.75 13.39
Forage Acacia macracantha leaves 0.224 0.30 0.62 0.030 0.021 0.07 0.90 1.66
Forage Alfalfa hay 0.183 0.25 0.65 0.290 0.180 0.00 0.92 9.08
Forage Alfalfa meal 0.192 0.28 0.66 0.067 0.125 0.00 1.00 9.25
Forage Barley hay 0.125 0.22 0.60 0.080 0.093 0.09 0.93 8.74
Forage Barley straw 0.043 0.47 0.27 0.12 0.257 0 0.95 6.07
Forage Barley straw, urea treated 0.07 0.7 0.2 0.08 0.098 0 0.98 6.07
Forage Bermudagrass hay 0.100 0.37 0.52 0.080 0.088 0.03 0.25 7.41
Forage Casava peel silage 0.058 0.14 0.39 0.070 0.080 0.39 1.00 13.02
Forage Chickpea straw 0.085 0.30 0.35 0.053 0.177 0.17 0.00 7.43
Forage Clover hay 0.178 0.39 0.5 0.14 0.067 0.05 0.96 8.33
Forage Corn silage 0.087 0.51 0.3 0.044 0.091 0.09 1 10.88
Forage Corn stalks 0.041 0.20 0.66 0.040 0.136 0.00 0.95 9.96
Forage Cottonseed hulls 0.041 0.30 0.35 0.053 0.177 0.17 0.00 6.36
Forage Dehydrated alfalfa pellets 0.192 0.28 0.66 0.07 0.13 0 1 9.25
Forage Flemingia macrophylla leaves 0.112 0.13 0.13 0.002 0.017 0.73 0.96 10.78
Forage Gliricidia leaves 0.183 0.29 0.45 0.074 0.250 0.01 1.00 10.78
Forage Grass hay 0.133 0.37 0.52 0.081 0.09 0.03 0.02 8.92
Forage Grass hay, mixed 0.106 0.37 0.5 0.09 0.1 0.03 0.05 7.43
Forage Grass silage 0.14 0.63 0.31 0.13 0.058 0.09 1 9.48
Forage Groundnut (peanut) hulls 0.078 0.23 0.76 0.050 0.087 0.00 0.00 2.22
Forage Guatemala grass 0.087 0.23 0.68 0.020 0.089 0.00 0.25 7.43
Forage Guinea grass 0.094 0.06 0.57 0.073 0.089 0.28 0.25 7.43
Forage Krishnachura leaves 0.145 0.18 0.60 0.028 0.200 0.02 0.92 10.78
Forage Leucaena leaves 0.269 0.30 0.62 0.030 0.021 0.07 0.90 10.78
Forage Mulberry (Morus alba) leaves 0.208 0.20 0.50 0.026 0.200 0.10 0.92 11.34
Forage Napier grass 0.078 0.46 0.52 0.110 0.022 0.00 0.02 6.88
Forage Oat hay 0.058 0.35 0.53 0.043 0.103 0.02 0.93 8.03
Forage Oat/sorghum hay 0.093 0.32 0.53 0.05 0.1 0.06 0.94 8.18
Forage Oaten chaff 0.091 0.35 0.53 0.04 0.07 0.05 0.93 5.31
Forage Orchardgrass hay 0.130 0.25 0.69 0.110 0.061 0.00 0.96 8.16
Forage Paragrass (Brachiaria mutica) hay 0.092 0.09 0.70 0.054 0.110 0.10 0.95 6.13
Forage Peanut hay 0.171 0.39 0.50 0.140 0.099 0.02 0.96 8.36
Forage Rhodesgrass hay 0.066 0.28 0.53 0.050 0.167 0.02 0.96 8.36
Forage Rice straw (NaOH treated) 0.035 0.36 0.37 0.067 0.292 0.00 0.95 6.50
Forage Rice straw (urea treated) 0.035 0.11 0.66 0.034 0.138 0.09 0.95 6.50
Forage Rice straw 0.053 0.41 0.42 0.023 0.168 0.00 0.95 5.57
Forage Sesbania grandiflora leaves 0.208 0.11 0.79 0.183 0.100 0.01 0.96 9.30
Forage Sorghum-sudan hay 0.094 0.28 0.53 0.050 0.128 0.06 0.95 8.49
Forage Sugar beet pulp silage 0.1 0.05 0.91 0.02 0.06 0 0.96 7.62
Forage Sugar cane bagasse 0.030 0.03 0.49 0.049 0.315 0.17 0.96 4.83
Forage Wheat straw 0.048 0.09 0.51 0.014 0.292 0.10 0.95 6.19
Mineral/Vitamin Supplement Mineral/Vitamin Supplement 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

1SolP = Soluble CP (g/g total CP).
2SDP = Slowly degradable protein (g/g total CP).
3kd = rate of degradation of SDP (/h).
4ADIP = acid detergent insoluble CP (g/g total CP).
5DRUDP = ruminally undegraded but intestinally digestible protein (g/g total CP). Calculated as the difference between total CP and the sum of SolP, SDP, and ADIP.
6NPCP = non-protein CP (g/g SolP). Derived from NRC (1996).
7ME = Metabolizable energy (MJ/kg)

    

MP intake (g):
MP intake (% DM):

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.