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ND-ICP, w/or without Sodium Sulfite

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NDF and ND-ICP (Neutral Detergent Insoluble Crude Protein) Values can be determined by using or not using sodium sulfite in the procedure.  The sodium sulfite is used to remove protein remaining in the NDF residue.  The International Association of Analytical Chemists (AOAC) and National Forage Testing Association (NFTA) recommend performing NDF with the use of sodium sulfite. Studies show that sodium sulfite is critical for the removal of proteinaceous matter in heated or cooked feed and is essential to the NDF method. (Dr. Mertens, personal communication)

Effect of sodium sulfite on NDF. Journal of AOAC International.
Vol. 79, No.1, 1996, Hintz, Mertens.

Sample NDF without Sodium Sulfite With Sodium Sulfite
Brewer's Grains 52.3 40.9
Distiller's Grains 38.6 27.9
Meat Scraps 30.8 22.2
Soybean Meal 18.5 12.4
Brome Grass 66.6 64.2
Ladino Clover 31.9 30.3
Alfalfa Silage 43.6 42.2
Corn Silage 36.1 34.7
Corn Grain 11.4 10.1
Alfalfa Hay 45.5 44.3
Citrus Pulp 21.3 20.2
Soy Plus 19.3 16.0

ND-ICP is the amount of protein that remains in the NDF residue.  ND-ICP has multiple purposes in ration balancing and computer models.

  1. Dairy NRC 2001 - ND-ICP is used to calculate NFC and TDN calculations.

    • NFC = 100-((CP (NDF-NDICP) Fat Ash))

    • The ND-ICP is subtracted from NDF so that the protein remaining in NDF is not double counted since protein is already subtracted as CP.

  2. CPM and CNCPS have used various combinations of NDR, aNDF, aNDFom, NDICP, and NDICPss within their programs.  For CNCPS 6.5 and higher, aNDFom and NDICPss are preferred.  


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