Effects of spontaneous heating on fiber composition, fiber digestibility, and in situ disappearance kinetics of neutral detergent fiber for alfalfa-orchardgrass hays

Abstract

"Effects of spontaneous heating on fiber composition, fiber digestibility, and in situ disappearance kinetics of neutral detergent fiber for alfalfa-orchardgrass hays" (2009 aBStraCt During 2006 and 2007, forages from 3 individual hay harvests were utilized to assess the effects of spontaneous heating on concentrations of fiber components, 48-h neutral detergent fiber (NDF) digestibility (NDFD), and in situ disappearance kinetics of NDF for large-round bales of mixed alfalfa (Medicago sativa L.) and orchardgrass (Dactylis glomerata L.). Over the 3 harvests, 96 large-round bales were made at preset bale diameters of 0.9, 1.2, or 1.5 m, and at moisture concentrations ranging from 9.3 to 46.6%. Internal bale temperatures were monitored daily during an outdoor storage period, reaching maxima (MAX) of 77.2°C and 1,997 heating degree days >30°C (HDD) for one specific combination of bale moisture, bale diameter, and harvest. Concentrations of all fiber components (NDF, acid detergent fiber, hemicellulose, cellulose, and lignin) increased in response to spontaneous heating during storage. Changes in concentrations of NDF during storage (poststorage -prestorage; ΔNDF) were regressed on HDD using a nonlinear regression model (R 2 = 0.848) that became asymptotic after ΔNDF increased by 8.6 percentage units. Although the specific regression model varied, changes (poststorage -prestorage) in concentrations of acid detergent fiber, cellulose, and lignin also increased in nonlinear relationships with HDD that exhibited relatively high coefficients of determination (R 2 = 0.710 to 0.885). Fiber digestibility, as determined by NDFD, was largely unaffected by heating characteristics except within bales incurring the most extreme levels of HDD or MAX. In situ assessment of ruminal NDF disappearance kinetics indicated that disappearance rate (K d ) declined by about 40% within the range of heating incurred over these hay harvests. The change in K d during storage (ΔK d ) was related closely to both HDD and MAX by nonlinear models exhibiting high R 2 statistics (0.907 and 0.883, respectively). However, there was no regression relationship between changes (poststorage -prestorage) in effective ruminal disappearance of NDF and spontaneous heating, regardless of which heating measure was used as the independent variable. The close regression relationship between ΔK d and measures of spontaneous heating indicates clearly that ruminal NDF disappearance was altered negatively by some direct or indirect aspect of spontaneous heating. However, it was equally apparent that these effects were offset by an expanding pool of dry matter recovered as potentially degradable NDF.

Cell Wall Composition and Ruminant Digestibility of Various Maize Tissues Across Development

“…The detergentbased methods are a well-established method to measure composition concentrations. Forage quality laboratories and research groups routinely use these methods [1,3,5,6,8,16,22]. Development of near-infrared spectroscopy (NIRS) calibrations based on the detergent-based methods can be used to predict these components in a high-throughput manner.…”

Influence of Airflow on Laboratory Storage of High Moisture Corn Stover

“…The more extensive hemicellulose degradation compared to cellulose degradation observed in the stored corn stover in this study is consistent with reported values for both aerobic and anaerobic biomass storage conditions. Cellulose enrichment and reduced hemicellulose levels have been documented in the composition of ensiled corn stover [41] and high moisture hay that selfheated during storage [45]. Increased hemicellulose loss compared to cellulose loss has also been documented for fungally degraded corn stover stored aerobically [46].…”

Influence of ensiling time and inoculation on alteration of the starch-protein matrix in high-moisture corn

“…Concentrations of N in ADF and NDF, expressed on a CP basis (ADICP or NDICP), were ascertained by refluxing samples in neutral or acid detergent in an Ankom 200 fiber analyzer (Fairport, NY) as defined by Coblentz and Hoffman, (2009). The residual CP concentration within the respective residues was determined by a combustion technique (AOAC, 1998).…”