Thomas, Martha 1980- (2013-05). Application of Fibrolytic Enzymes and Bacterial Inoculants to Sorghum Silage and Small-Grain Hay. Doctoral Dissertation.
Fibrolytic enzymes and microbial inoculants have potential to improve the value of feedstuff and feedstock. An experiment was conducted to determine the nutritive value, ensiling characteristics, and in situ disappearance kinetics of sorghum (Sorghum bicolor L.) silages pretreated with fibrolytic enzyme (xylanase plus cellulase: XC) or microbial [Promote ASB (Lactobacillus buchneri and L. plantarum); PRO] inoculants. The greatest yield was for cultivar PS 747 and the least for MMR 381/73 (MMR). Neutral detergent fiber (NDF) concentration was least for XC treated silage, and acid detergent fiber (ADF) concentration was least for XC and PRO treated silage. In vitro true digestibility (IVTD) was greatest for PRO treated Dairy Master BMR (DBMR), whereas, acid detergent lignin was least for PRO treated DBMR. Aerobic stability was not improved by PRO, however, aerobic stability of XC treated MMR was 63 h greater than the control. Generally, the in situ disappearance kinetics were improved with the application of XC and PRO, and XC had the greatest effect on silage with greater NDF and ADF concentrations. A second experiment was conducted to determine if the same application rates of either inoculant would reduce the fiber fraction of two cultivars each of wheat (Triticum aestivum L.) or oat (Avena sativa L.) hays. Forage was harvested twice during the tillering stage (H1) and (H2) and a third after grain harvest (H3). The IVTD was greater for oat than wheat due to a lesser fiber fraction. Forage from H2 had lesser NDF and ADF and greater CP and IVTD concentrations. In situ DM, NDF, ADF, and ERD were greater for wheat and oat at tillering than stover and NDF and ERD were greater for Harrison than Fannin at tillering. Treatment of oat or wheat hays with XC or PRO enhanced in situ disappearance kinetics. Both XC and PRO may be used to reduce the fiber fractions of sorghum silage and small-grain hay. Additionally, it appears the inoculant PRO can be used to improve fermentation characteristics of sorghum silage.