Low-infrastructure filter bag technique for neutral detergent fiber analysis of forages

We tested a water bath filter bag technique (WB) for analysis of neutral detergent fiber (NDF) versus a standard filter bag technique (ANKOM). The principal difference between WB and ANKOM was absence of a pressurized chamber for WB. The NDF method we used (aNDF) did not include sodium sulfite. One-hundred and ninety-six diverse forage and silage samples were gathered from Vietnam and New York State including: 40 C3 grasses, 122 C4 grasses, 21 legumes and 13 silages. Samples were completely randomized for parallel processing in ANKOM and WB. Water bath aNDF levels were strongly correlated with ANKOM (r2 = 0.995) with an overall mean difference of 6.93 g/kg dry matter, and can be described by the equation: ANKOM aNDF (g/kg DM) = 0.9963 × Water Bath aNDF − 4.536. Intercept and slope were not different from zero (P = 0.1953) and one (P = 0.4828), respectively. Unique intercepts and slopes by sample classification (C3 grasses, C4 grasses, legumes, silages) were significant in a multivariate model, but may not be necessary based on the strong overall relationship between ANKOM and WB aNDF. Furthermore, duplicate repeatability for ANKOM and WB was not different. The water bath method is viable for NDF analysis of diverse forage and silage samples, and could provide a low-infrastructure efficient alternative for low-budget laboratories.