Comparison of in vitro methods to quantify the dry matter and neutral detergent fiber digestibility of forages and concentrates

ABSTRACT The objective was to compare in vitro digestibility of dry matter (IVDMD) and neutral detergent fiber (IVNDFD) of forages and concentrates obtained using the incubators DaisyII and TE-150, and filter bags F57 (Ankon®) or non-woven textile (NWT - 100g/m²) in comparison with the values obtained using the Tilley and Terry (1963) method. Twenty-five samples of concentrates and 25 samples of forages were used. There were no differences between filter bags (P>0.39) for IVDMD of forages. Higher IVDMD (P<0.01) were observed for TE-150 compared to DaisyII. Estimates of IVDMD obtained with incubators and filter bags were higher (P<0.01) than those obtained with the Tilley and Terry (1963) method. Higher IVNDFD (P<0.01) were obtained with filter bags F57 regarding to NWT and TE-150 when compared to DaisyII. All values of the IVNDFD obtained with incubators and filter bags were higher (P<0.01) than those obtained with the Tilley and Terry (1963) method. Both IVDMD and IVNDFD variables were greater using TE-150 incubator than using DaisyII (P<0.04). Estimates obtained using NWT filter bags were higher (P<0.01) than F57 filter bags. All methods were positively and strongly correlated (P<0.01) to each other for IVDMD and IVNDFD. The repeatability and variances among samples for IVDMD and IVNDFD were similar among methods. In conclusion, all methods were similarly able to discriminate samples.