Gravimetric determination of acid detergent fiber and lignin in feed: interlaboratory study

On the basis of AOAC Official Method 973.18, a collaborative study was performed to determine fractions of acid detergent fiber (ADF) and lignin (ADL) in animal feed. The study used 6 animal feed and forage samples as blind duplicates and involved 22 participants from 7 countries. The samples analyzed covered a range from 3.5 to 70% ADF and from <1 to 20% ADL. Repeatability standard deviations ranged from 0.27 to 0.95% for ADF and from 0.08 to 0.59% for ADL. The reproducibility standard deviations ranged from 0.56 to 2.44% for ADF and from 0.52 to 2.09% for ADL. Analyzed samples comprised clover and grass silages, soy meal, cattle feed, wheat, and sawdust. The studied method has been published as the EN ISO 13906:2008 standard.