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Title: The control and manipulation of silage fermentation
Author: Wayman, James
ISNI:       0000 0001 3564 7195
Awarding Body: University of Glasgow
Current Institution: University of Glasgow
Date of Award: 1993
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A series of experiments was conducted to investigate the mechanisms of the control and manipulation of silage fermentation. Preliminary experiments, using silage additives conventionally described as fermentation inhibitors and fermentation stimulants, demonstrated the extent to which the chemical composition of silage may be manipulated (Chapter 3). In Experiment 1, high levels of addition of formic acid or a mixture of ammonium hexaformate, ammonium hexapropionate and caprylic acid (more than 6 1/t) inhibited fermentation and preserved 78- 81 % of the water soluble carbohydrate content of the forage ensiled. These additives at lower levels of addition and mixed ammonium tri-hydrogen tetraformate and anmionium tri-hydrogen tetrapropionate encouraged ethanol accumulation, presumably by yeasts, in the later stages of ensilage. In Experiment 2, an inoculant of Lactobacillus plantarum encouraged a rapid homolactic fermentation in the early stages of ensilage and appeared to deter undesirable micro-organisms but adding sucrose (40 kg/t grass) with the inoculant resulted in the accumulation of 61 g ethanol/kg dry matter (DM) silage, suggesting that yeasts assumed a more prominent role in the fermentation. Addition of sodium bicarbonate with the inoculant and sucrose sustained the homolactic fermentation (maximum 194 g lactic acid/kg DM after 120d) by encouraging a relatively high pH, and this vigorous lactic fermentation seemed to be effective against yeast activity (maximum 13 g ethanol/kg DM). In Experiment 3, the effects of some of these manipulations on microbial numbers were examined. Microbial numbers were not a reliable indication of the chemical composition of the silage.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Agricultural chemistry & fertilizers