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- TDN = total digestible nutrients (%)
- NE = net energies of maintenance (NEm), gain (NEg), or lactation (NEl) as “Mcal/lb”
- ME = metabolizable energy (Mcal/lb)
- DE = digestible energy (Mcal/lb)
- CProt = Crude protein (%)
- ADF = acid detergent fiber (%)
- CF = crude fiber (%)
- NDF = neutral detergent fiber (%)
- ADICP = acid detergent insoluble crude protein (%)
- NDICP = neutral detergent insoluble crude protein (%)
- CFat = crude fat or ether extract (%)
- Ash = ash (%)
- LIG = lignin (%)
- TDN% = 95.673 - (1.224 * ADF)
- NEl Mcal/lb = 1.0098 - (0.0136 * ADF)
- TDN% = 93.53 - (1.03 * ADF)
- NEl Mcal/lb = 1.6438 - (0.0241 * ADF) …derived from NEl = -0.5448 + (0.0234 *TDN)
- TDN% = 82.19 - (0.498 * ADF) …derived from TDN = 81.41 - [0.60 * (-1.30 + (0.83 * ADF)]
- NEl Mcal/lb = 0.8597 - (0.0055 * ADF) …derived from NEl = (-0.12 + (0.0245 * TDN)) * 0.4543
- TDN% = 99.72 - (1.927 * ADF)
- NEl Mcal/lb = 1.036 - (0.0203 * ADF)
- TDN% = 92.22 - (1.535 *ADF)
- NEl Mcal/lb = 0.9050 - (0.0026 * ADF)
- TDN% = 86.836 - (0.6584 * ADF) …derived from TDN = 31.4 + (53.1 * NEl)
- NEl Mcal/lb = 1.044 - (0.0124 * ADF)
- TDN% = 81.41 - (0.48 * ADF) …derived from TDN = 81.41 - (0.60 * CF), where CFiber = ADF * 0.8
- NEl Mcal/lb = (TDN * 0.234) - 0.5448
- TDN% = 102.33 - (1.1135 * ADF) …derived from TDN = 4.898 + (89.896 * NEl)
- NEl Mcal/lb = 1.085 - (0.0124 * ADF)
- TDN% = 98.645 - (1.0686 * ADF) …derived from TDN = 4.898 + (89.896 * NEl)
- NEl Mcal/lb = 1.044 - (0.0119 * ADF)
- TDN% = 102.56 - (1.1404 * ADF) …derived from TDN = 4.898 + (89.896 * NEl)
- NEl Mcal/lb = 1.0876 - (0.0127 * ADF)
- TDN% = 102.56 - (1.1404 * ADF) …derived from TDN = 4.898 + (89.896 * NEl)
- NEl Mcal/lb = 1.0876 - (0.0127 * ADF)
- TDN% = 88.094 - (0.7121 * ADF) …derived from TDN = 4.898 + (89.896 * NEl)
- NEl Mcal/lb = 0.9265 - (0.00793 * ADF)
- TDN% = 102.33 - (1.1135 * ADF) …derived from TDN = 4.898 + (89.896 * NEl)
- NEl Mcal/lb = 1.085 - (0.0124 * ADF)
- TMR (total mixed rations)
- TDN% = 93.53 - (1.03 * ADF)
- NEl Mcal/lb = 0.9859 - (0.0115 * ADF) …derived from NEl = (-0.12 + (0.0245 * TDN)) * 0.454
- DE = TDN% * 0.02002
- ME = TDN% * 0.01642
- NEm Mcal/lb = (1.2854* ME) - (0.1787* ME * ME) - 0.495 ...derived from NE Mcal/lb = [(1.37* ME) - (0.138 * ME * ME) + (0.0105 * ME * ME * ME) – 1.12] * 0.4536, where ME is expressed as Mcal/kg
- NEg Mcal/lb = (1.3219 * ME) - (0.2378* ME * ME) - 0.7333 ...derived from Neg Mcal/lb = [(1.42* ME) - (0.174 * ME * ME) + (0.0122 * ME * ME * ME) – 1.65] * 0.4536, where ME is expressed as Mcal/kg
- TDN% = 85.65 + (CProt x 0.362) - (ADF x 0.825)
¶ Grains and Dry Feeds
- TDN% = 93.59 - (ADF x 0.936)
- TDN% = 81.38 + (CP x 0.36) - (ADF x 0.77)
- TDN% = 83.088 + (CProt x 0.0353) - (ADF x 0.788)
- TDN% = 83.33 - (ADF x 0.795)
- TDN% = 87.10 - (ADF x O. 848)
- TDN% = 93.75 + (CProt x 0.362) - (ADF x 1.06)
- TDN% = 88.96 + (CProt x 0.36) - (ADF x 0.996)
- TDN% = 90.82 + (CProt x 0.0353) - (ADF x 1.01)
- TDN% = 93.53 - (ADF x 1.03)
- TDN% = 91.13 - (ADF x 1.02)
- NEm Mcal/lb = ((0.01317 x TDN) – 0.13166 ...derived from NEm = ((0.029 x TDN) - 0.29) x 0.454
- NEg Mcal/lb = ((0.01317 x TDN) – 0.4585 ...derived from NEg = ((0.029 x TDN) - 1.01) x 0.454
- NEl Mcal/lb = ((TDN x 0.011123) - 0.05448) ...derived from NEl = ((TDN x 0.0245) - 0.12) x 0.454
- TDN%_fat = TDN * ((1.76 * CFat) - 6.04) ...derived from TDN_fat = TDN * [((100 - (Cfat - 4)) / 100) + (((Cfat - 4) / 100) * 177]
- NEm_fat Mcal/lb = NEm * ((0.0165 * CFat) + 0.934) ...derived from NEm_fat = NEm * [((100 - (Cfat - 4)) / 100) + (((Cfat - 4) / 100) * 2.65]
- NEg_fat Mcal/lb = NEg * ((0.0165 * CFat) + 0.934) ...derived from NEg_fat = NEg * [((100 - (Cfat - 4)) / 100) + (((Cfat - 4) / 100) * 2.65]
- NEl _fat Mcal/lb = NEm * ((0.0165 * CFat) + 0.934) ...derived from NEl_fat = NEl * [((100 - (Cfat - 4)) / 100) + (((Cfat - 4) / 100) * 2.65
- ME_fat Mcal/lb = ME * ((0.0247 * CFat) + 0.9011) ...derived from ME_fat = ME * [((100 - (Cfat - 4)) / 100) + (((Cfat - 4) / 100) * 3.473]
¶ OARDC (Ohio Agricultural Res. and Dev. Center)
- TDN%_1X_conc = [CProt * (1 - 0.004 * (ADICP / CProt * 100))] + [0.75 * (((NDF - NDICP) - LIG) * (1 - (LIG / (NDF - NDICP)) ^0.667))] + [0.98 * (100 - CProt - NDF + NDICP - ASH - CFat)] + [(CFat - 1) * 2.25] – 7
- DE_1X_conc = 0.056 * [CProt * (1 - 0.004 * (ADICP / CProt * 100))] + 0.042 * [0.75 * (((NDF - NDICP) - LIG) * (1 - (LIG / (NDF - NDICP)) ^0.667))] + 0.042 * 0.98 * (100-CProt-NDF+NDICP-ASH-CFat) + 0.094 * (CFat-1) - 0.31
- DE_3X = DE_1X_conc * 0.92 ...energy values for intake levels at three times (3X) that required for maintenance
- ME_3x = ((1.01 * (DE_1X * 0.92) - 0.45) + 0.0046 * (CFat - 3))
- NEl_3X = ((0.703 * ME_3X - 0.19) + (0.097 * ME-3X + 0.19 / 97) * (CFat - 3)) 3
- TDN%_1X_forage = (CProt * (exp (-0.012 * (ADICP / CProt * 100)))) + (0.75 * (((NDF - NDICP) - LIG) *(1 - (LIG / (NDF - NDICP)) ^0.667))) + 0.98 * (100 - CProt - NDF + NDICP - ASH - CFat) + (CFat - 1) * 2.25 - 7)))
- DE_1X_forage = (0.056 * (CProt * (EXP (-0.012 * (ADICP /CProt* 100)))) + 0.042 *(0.75 * (((NDF - NDICP) - LIG) *(1 - (LIG / (NDF - NDICP)) ^0.667))) + 0.042 * 0.98 * (100 - CProt - NDF + NDICP - ASH -CFat) + 0.094 * (CFat- 1) - 0.31)
- DE_3X = DE_1X_forage * 0.92 ...energy values for intake levels at three times (3X) that required for maintenance
- ME_3x = ((1.01 * (DE_1X * 0.92) - 0.45) + 0.0046 * (CFat - 3))
- NEl_3X = ((0.703 * ME_3X - 0.19) + (0.097 * ME-3X + 0.19 / 97) * (CFat - 3))
- NFE (%) = 100 – (CProt % + CF % + EE % + Ash %)
- NFC (%) = [100 - (%NDF + %CProt + %Fat + Ash)] …sometimes called “Nonstructural Carbohydrates (NSC)”
- NFC (%) = [100-((%NDF - %NDFCP)+ %CProt + %Fat + Ash)] …Cornell Net Carbohydrate / Protein System
Adams, et. al. 1995. "Table 5.25, Regression equations for estimating energy values of various feeds" in NRAES-63, Dairy Reference Manual. Northeast Reg. Agric. Eng. Serv. Coop Ext., Ithaca NY
Clemson University. 1996. Formulas for feed and forage analysis calculations, rev. 8/21/96. Agric.l Service Lab., Clemson University, Pendleton SC. 4 pg.
NRC. 1989. "The Energy Values of Feeds" in Nutrient Requirements of Dairy Cattle, Sixth Revised Edition. Nat’l Academy of Sciences. pg 9.
NRC. 1996. "Energy" in Nutrient Requirements of Beef Cattle, Seventh Revised Edition. Nat’l Academy of Sciences. pg 4.
Weiss,. 2007. Calculations from Excel spreadsheet via personal communication. Dept of Animal Sciences, Ohio Agric. Res. & Dev. Center, Ohio State University, Wooster OH
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