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Forage Conservation Need for conservation Feeding during drought or floods Utilizing surplus forage Transport of feed Methods of Conservation Hay Silage Haylage Hay Grasses are cut at optimum growth stage Left in the field to dry Machine used to turn over grass to aid drying (tedder) Dried grass swept in rows (windrow) Hay baler used to compress dried grass – cubes or big round bales Can also be used to conserve rice straw Big bale hay Padi straw hay Problems with making hay Need plenty of sunshine – 3 consecutive days without rain Easily spoilt by moulds if not quickly dried Requires heavy investment in machinery Large storage area is required Can be a fire hazard Haylage Forage that is baled at a higher moisture content than dry hay and then stored in a sealed plastic wrap. Because of the high moisture level and air-tight environment, the forage ferments and is preserved by acid production during fermentation. Advantages of Haylage Decreased curing time needed from cutting to baling makes weather less of a factor in forage harvesting. Potential for more timely harvest of large quantities of forage. Decreased need for mechanical handling and time curing to dry the forage reduces the loss of leaves, the most digestible part of the plant. Potential for higher feed quality bale through leaf preservation and possible nitrate reduction. Disadvantages of haylage Increased harvest cost per bale vs. conventional cured hay. Disposal of used plastic wrap. More likely to spoil as compared to silage in traditional silos. Risk of forage spoilage if integrity of wrap is not maintained. Birds and rodents can puncture plastic and holes must be covered. Transportation of bales is limited due to cost of moving high-moisture bales. Advantages of silage More palatable than hay Not dependent on weather Can be kept longer without deterioration Not easily inflammable Requires less storage area How haylage is made The forage is cut as if for haymaking, but is baled at 50 to 60% moisture rather than at 18-20% moisture. Mechanised Silage Making Principle of Silage conservation Forages are conserved in an environment of low pH (4.2) and anaerobic conditions where biochemical processes and activities of decomposing aerobic bacteria and fungi are inhibited Materials which can be ensiled Grasses Sorghum Maize Oil palm fronds Crop byproducts (pineapple skin, cocoa pods) Factors required for good silage Airtight – to provide anaerobic conditions Moisture content in forage 65-75% Adequate soluble carbohydrates (>3%) Compaction of materials to exclude air Not contaminated with foreign matter e.g. soil Silage making process Grass is cut at optimum growth stage Grass chopped up Silage making process (2) Chopped grass filled in silo: Bunker silo Pit silo Tower silo Container Chopped grass compressed to exclude air Silo is sealed airtight Left for at least 21 days to complete ensilation Tower Silo Phases of fermentation Baled silage Baled Silage in N.Z. Baled silage Baled Silage The Silager An invention in Institut Haiwan Kluang Able to mechanically compress silage in a bin Mechanical press SILAGER II collection conveyor Forage chopped Entry for fresh fodder Phase I Grass is put in silo Respiration continues Oxygen is used up CO2 and heat is released Temperature rises Phase 2 Acetic acid is released pH declines from 6.0 to 4.2 Phase 3 Lactic acid is released Acetic acid declines Phase 4 Lactic acid production continues Temperature declines Bacterial activity stops at pH 4.0 Characteristics of Good Silage pH < 4.5 Lactic acid 3 -13% Butyric acid < 0.2% Colour: yellowish to brownish green Odour: sweet smelling (vinegar smell) Wetness – no seepage Palatability – readily accepted by animals Nutritive value – almost similar to original material Additional steps for making good silage Chop the material to allow easy compaction Use additives: corn, soybean, molasses to increase soluble carbohydrates and protein (esp. if < 3% soluble carbohydrate) Use enzymes to aid fermentation Silage additives A. Stimulants aid in the growth of the lactic acid bacteria and the production of their acids so as to reduce silage pH at a faster rate. Silage additives B. Inhibitors help to slow down unwanted silage degradation. For example, inhibitors may reduce mold growth or reduce the breakdown of plant proteins. Silage additives Bacterial Inoculants are the main type of silage additive used in the U.S (about 70% of all additives). They contain inactive bacteria that become active once they are put on the wet forage. Silage additives Sugars such as molasses, glucose, and dextrose can be added to forage to increase the lactic acid content of the silage by supplying more food (sugar) for the lactic acid bacteria to grow on. Silage additives Enzymes are proteins that speed up the break down of plant carbohydrates to sugars Common sources of enzymes include, Aspergillus oryzae, Aspergillus niger, and Bacillus subtillus.
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