Quality Analysis of Summer‐Annual Forages. III. Prediction of Wet Silage In Vitro Dry Matter Disappearance from Chemical Constituents1

Abstract

AbstractSamples for the determination of silage quality are generally dried prior to analysis even though some silage constituents are lost during drying. The objectives of this study were to examine the prediction of wet silage in vitro dry matter disappearance (IVDMD) from analysis of dried samples using both oven‐dried and freeze‐dried fodder and silage. Frozen, wet silage was ground to pass a 1‐mm screen using liquid N as a cryostat. The IVDMD of ground, frozen silage (GFS) was found to be most closely related to the IVDMD of freeze‐dried fodder (FD), with GFS IVDMD = 24.7 + 0.99 (FD IVDMD) and r2 = 0.76**. Weaker relationships were found with freeze‐dried silage (FDS) (r2=0.46**), oven‐dried silage (ODS) (r2=0.35**), and oven‐dried fodder (OD) (r2=0.34**). The relationships between the IVDMD of GFS and fiber fractions of neutral detergent fiber (NDF), acid detergent fiber (ADF), permanganate lignin, apparent cellulose, apparent hemicellulose (NDF—ADF), and the ADF/lignin ratio as independent variables were examined using stepwise regression. Freeze‐dried fodder lignin (r2=0.44) and OD ADF (r2=0.37) were the two single fractions most closely related to wet silage IVDMD. Correlations from the Van Soest fractions alone in single variable regressions were not improved when using stepwise multiple regression analysis.