ARS | Publication request: THE ESTIMATION AND UTILIZATION OF IN VITRO DIGESTION RATES

Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: July 10, 1994
Publication Date: N/A

Technical Abstract: In vitro neutral detergent fiber (NDF) digestion rate (k) has attracted interest because it may influence forage quality. In vitro digestion rate of NDF is difficult to measure because in order to fit the required nonlinear equations, 9 to 12 observations at times ranging from 0 to 96 hours are needed for each forage to be tested. Near infrared reflectance spectroscopy (NIRS) may provide means of estimating the required data. Laboratory analyses were performed to estimate k and surface area fermentability (SAF) in Panicum virgatum germplasm. Direct estimates of k (R2=0.18) and surface area fermentability (SAF) (R2=0.12) with NIRS were not satisfactory but estimates of NDF at each hour were fitted to nonlinear equations to estimate k and SAF. These k (r2=0.47) and SAF (r2=0..57) were correlated with laboratory values. Considering the difficulty in obtaining stable estimates of k and SAF, careful calibration of NIRS for prediction of residual NDF at times ranging from 0 to 96 hours may provide an acceptable means of obtaining these nonlinear estimates of fiber digestion rate.