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" Enzyme, inoculant, and formic acid effects on silage quality of orchardgrass and alfalfa "
E. M. G. T. Nadeau
D. R. Buxton
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Latin Dissertation
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English
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| Record Number
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1113295
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TLpq304177690
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| Main Entry
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D. R. Buxton
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E. M. G. T. Nadeau
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| Title & Author
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Enzyme, inoculant, and formic acid effects on silage quality of orchardgrass and alfalfa\ E. M. G. T. NadeauD. R. Buxton
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| College
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Iowa State University
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| Date
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1995
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1995
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| Degree
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Ph.D.
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| Page No
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168
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| Abstract
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Limited information exists on the interaction between silage treatment and plant species and their effects on silage composition, intake, and digestion. Additionally, the effects of plant maturity in the speciesusd\timesusdtreatment interaction needs to be evaluated. This study was conducted to compare the effects of cell-wall degrading enzymes, bacterial inoculant (Lactobacillus plantarum and Pediococcus cerevisiae), and formic acid on composition, intake, and digestion of orchardgrass (Dactylis glomerata L.) and alfalfa (Medicago sativa L.) silages. Cellulase (from Trichoderma longibrachiatum) alone, or combined with inoculant, inoculant and pectinase (from Aspergillus niger), or formic acid, was applied to wilted herbage at three maturities before ensiling for 60 d. All treatments, except pectinase, were used in an in vivo digestibility trial with lambs. Silages treated with cellulase+formic acid were also used in an in situ digestion trial with dairy cows to measure ruminal cell-wall digestion over time. Neutral detergent fiber (NDF) concentration in alfalfa and orchardgrass silage decreased with increasing cellulase (minimum carboxymethylcellulose activity: 2500 IU mL up to 10 and 20 mL kg herbage, respectively. Because of lower lignin and greater initial NDF concentration, cellulolytic cell-wall hydrolysis was greater in orchardgrass (30%) than in alfalfa (12%) silage. Cell walls of immature plants were degraded 61% more than those of mature plants. Increasing cellulase increased reducing sugar concentration by two and nine times in alfalfa and orchardgrass silage, respectively. There were generally no effects of increased cellulase application on fermentation characteristics. Cellulase applied at 2 mL kg produced enough sugar to improve silage fermentation. Cellulase alone generally had a greater effect on fermentation characteristics in alfalfa than in orchardgrass silage. Addition of inoculant improved homolactic fermentation in cellulase-treated silage. Formic acid treatment restricted fermentation and proteolysis and increased sugar concentration in cellulase-treated silages. Averaged across plant species, cellulase+inoculant increased dry-matter intake of lambs by 8% and cellulase+formic acid increased dry-matter intake by 13% compared with control silage. Most of the effect was from formic acid in the enzyme+formic acid treated silage. Because cellulase degraded much of the cell walls to sugars during ensiling, cellulase-treated orchardgrass silage caused 25% lower NDF intake than control silage. Furthermore, because cellulase degraded the most digestible portion of the cell walls during ensiling, cellulase+formic acid treated orchardgrass and alfalfa silages had 39 and 22% lower extent of ruminal NDF digestion than control silages. However, total NDF degradation, including that during ensiling and ruminal fermentation, was greater for cellulase+formic acid treated than for control silage during early hours of ruminal fermentation. Thus, cellulase combined with formic acid can improve silage utilization by high-producing ruminants, where short rumen retention time and high rate of passage limit forage digestion.
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Agronomy
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Biological sciences
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