Browsing Grassland Science by Subject "Precision-chop silage"
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Factors influencing the conservation characteristics of baled and precision-chop grass silagesThe composition of baled silage on Irish farms frequently differs from that of comparable precision-chop silage. This paper concerns a field-scale study designed to investigate: (a) the effects of number of layers (2, 4, 6 or 8) of polyethylene stretch film and the duration of storage (7 vs. 18 months) on the conservation characteristics of baled silage, and (b) the conservation characteristics of baled (4 layers of stretch film) and precision-chop silages. All silages were made following three durations of wilting (0, 24 or 48 h). Wilting restricted silage fermentation, with silage pH being highest (P<0.001) and the concentration of fermentation products lowest (P<0.001) for the 48 h wilt treatment. Wrapping bales in only 2 layers of polyethylene stretch film resulted in extensive visible mould growth, but mould growth was practically eliminated by the application of 4 or more layers of film. Silage fermentation characteristics were generally improved by wilting, and by 4 compared to 2 layers of stretch film. Extending the storage duration of baled silage from 7 to 18 months reduced (P<0.001) the concentration of fermentation products and increased in-silo fresh weight losses (P<0.001) and visible mould growth. Whereas 4 layers of conventional stretch film are normally sufficient, 6 layers may be necessary to prevent mould growth when bales of unwilted silage are stored for a second season. Under good farm-management conditions differences observed between baled and precision-chop silages probably result mainly from differences in the concentration of dry matter in herbage at ensiling.
Manipulating the ensilage of wilted, unchopped grass through the use of additive treatmentsBaled silage composition frequently differs from that of comparable conventional precision-chop silage. The lower final concentration of fermentation products in baled silage makes it more conducive to the activities of undesirable microorganisms. Silage additives can be used to encourage beneficial microbial activity and/or inhibit detrimental microbial activity. The experiment was organised in a 2 (chop treatments) × 6 (additive treatments) × 2 (stages of ensilage) factorial arrangement of treatments (n = 3 silos/treatment) to suggest additive treatments for use in baled silage production that would help create conditions more inhibitory to the activities of undesirable microorganisms and realise an outcome comparable to precision-chop silage. Chopping the herbage prior to ensiling, in the absence of an additive treatment, improved the silage fermentation. In the unchopped herbage, where the fermentation was poorer, the lactic acid bacterial inoculant resulted in an immediate increase (P < 0.001) in lactic acid concentration and a faster decline (P < 0.001) in pH with a subsequent reduction in butyric acid (P < 0.001) and ammonia-N (P < 0.01) concentrations. When sucrose was added in addition to the lactic acid bacterial inoculant, the combined treatment had a more pronounced effect on pH, butyric acid and ammonia-N values at the end of ensilage. The formic acid based additive and the antimicrobial mixture restricted the activities of undesirable microorganisms resulting in reduced concentrations of butyric acid (P < 0.001) and ammonia-N (P < 0.01). These additives offer a potential to create conditions in baled silage more inhibitory to the activities of undesirable microorganisms.