Forages: Two step process: First step: Partial dry matter adapted from Goering, H.K. and P.J. Van Soest. 1970. Forage Fiber Analysis. USDA Agricultural Research Service. Handbook number 379. U.S. Dept. of Agriculture. Superintendent of Documents, US Government Printing Office, Washington, D.C. 20402. Second step: Modified to 105°C for 3 hrs per National Forage Testing Association recommendations, 2002.

DDGS: NFTA 2.1.4 - Dry Matter by Oven Drying (105 ºC / 3 hr) (R2006).

Grains, mixed feeds, concentrates and by-products: Moisture in Animal Feed, Drying at 135°C (930.15). Official Methods of Analysis, 17th edition. 2000. Association of Official Analytical Chemists.

Fermentation Analysis

(Acetic, Propionic, Butyric, Isobutyric, Isovaleric, Valeric Acids and 1,2 Propanediol)

 3ml of sample extract is filtered through a 0.22 micron filter membrane.  An internal standard is added and a 0.5µL sub-sample is injected into a Perkin Elmer Clarus 580/590 Gas Chromatograph using a Stabiliwax-DA column.  Perkin Elmer, 710 Bridgeport Avenue, Shelton, CT 06484.

Goering, H.K. and P.J. Van Soest. 1970. Forage Fiber Analysis. USDA Agricultural Research Service. Handbook number 379. U.S. Dept. of Agriculture. Superintendent of Documents, US Government Printing Office, Washington, D.C. 20402.

Modifications:
Fiber residue from the ADF step is recovered on a 1.5um particle retention 7cm Whatman Glass Fiber Filter in a California Buchner Funnel instead of using a Gooch crucible. Greater surface area allows for better filtration. Fiber residue and filter is transfer to a capped tube and approx. 45 ml of 72% Sulfuric Acid is added. Tubes are gently agitated for 2 hours to insure that all fiber material is continually washed with acid. The contents of the tube after incubation in acid is filtered onto a second filter (same type as above) which is then rinsed, dried and weighed. The glass fiber filters and lignin residue are than ashed for 2 hours in a furnace to remove lignin organic matter. Finally, the filter and ash residue is weighed back and subtracted from the original weight to determine grams of lignin.

Starch Digestibility - In Vitro

 Goering, H. K. and P.J. Van Soest. 1970. Forage fiber analyses (apparatus, reagents, procedures, and some applications). Agric. Handbook 379. ARS, USDA, Washington, DC.

Duplicate 1 gram, 4 mm grind samples are run 3 different days and incubated in rumen fluid from lactating dairy cows and Van Soest buffer under continuous flow CO2 in 250 ml Erlenmeyer flasks in a stationary water batch.  After removal from water bath, sodium acetate is added to stop fermentation and the samples are chilled until processing.

Residue starch is determined by Starch Method: Hall, M.B. 2009. Analysis of starch, including maltooligosaccharides, in animal feeds: a comparison of methods and a recommended method of AOAC collaborative study.  JAOACI 92: 42-49. Correction for free glucose as described in Hall (2009).

Orskob, E.R. and McDonald, I. (1979) The Estimation of Protein Degradability in the Rumen from Incubation Measurements Weighed According to Rate of Passage.  The Journal of Agricultural Science, 92, 499.

Duplicate samples of 4 or 6 mm grind samples are put in 50 micron dacron bags then into the rumen of 3 lactating dairy cows in weighed mesh bags.  At the end of the time period samples are removed and soaked in cold water.  Sample bags are then rinsed and dried and ground for starch analysis using Hall 2009.