Author
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NADEAU, ELISABET - ISU |
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BUXTON, DWAYNE |
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Submitted to: Journal of the Science of Food and Agriculture
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 5/3/1996 Publication Date: N/A Citation: N/A Interpretive Summary: Ensiling is a controlled fermentation, in which existing lactic acid bacteria in the harvested crop ferment sugars to lactic acid that converts the perishable forage crop to a stable, stored feed source to be eaten later by ruminant livestock. When ensiling crops low in sugars, silage fermentation can be enhanced by adding sugar-producing enzymes to the forage before ensiling. In addition, lactic-acid-bacteria containing inoculants can be applied to the forage to increase the number of lactic acid bacteria on the crop. After the forages are mowed, they are usually wilted in the field to 60-70% plant moisture to minimize nutrient losses through seepage during ensiling. Occasionally, weather conditions cause forage to dry rapidly during wilting, resulting in less plant moisture than desired for optimal silage conditions. We conducted an experiment to determine the effects of an enzyme and a bacterial inoculant on the quality of orchardgrass and alfalfa ensiled at low moisture levels. The inoculant improved silage fermentation of orchardgrass, whereas both additives had only small effects on the quality of alfalfa silage. Livestock producers and their advisors, forage industry representatives, and forage researchers will be most interested in the results of this study. Technical Abstract: Limited information exists on the response of grass and legume silage to enzyme and bacterial inoculant treatments when wilted to drier than desired conditions. This study was undertaken to evaluate the impact of enzyme application rate, when combined with a bacterial inoculant, on the fermentation characteristics of orchardgrass and alfalfa ensiled at high dry-matter concentrations. Forages were wilted to near 600 g dry matter kg**-1 and enzyme, combined with inoculant, was applied at 0.30 ml kg**-1 herbage and two, four and eight times this concentration. Enzyme was also applied alone at 0.60 ml kg**-1. Wilted forages were ensiled in laboratory silos for 60 days. Effect of enzyme application rate on neutral detergent fibre concentrations of the silages was small and inconsistent. Averaged across species, only the intermediate enzyme concentrations decreased neutral detergent fibre concentration (P = 0.082). The limited cell-wall degradation was probably related to the high silage dry-matter and lignin concentrations. Enzyme combined with inoculant increased total fermentation, when averaged across species. In orchardgrass, enzyme combined with inoculant decreased pH and NH3-N concentration but increased the lactic:acetic acid ratio of control silage, with most of the effect caused by the inoculant. Enzyme, applied alone to alfalfa, had a higher lactic:acetic acid ratio than the control or when combined with the inoculant at the same enzyme rate. Thus, the effect of enzyme-inoculant mixtures on silage quality varied among plant species, with orchardgrass generally more responsive than alfalfa. |
