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Silage- Preserved Grass for Winter Feed. Slide 1. Factors That Affect Silage Quality. Use of additives Compaction Speed of filling & sealing the pit Wetness when cut Time of year ensiled. Silage Data. Increase in yield= longer growing period, increase photosynthesis & day length,
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Silage- Preserved Grass for Winter Feed Slide 1
Factors That Affect Silage Quality • Use of additives • Compaction • Speed of filling & sealing the pit • Wetness when cut • Time of year ensiled
Silage Data Increase in yield= longer growing period, increase photosynthesis & day length, Variation in digestibility= grass develops flower, high % cellulose, reduction in starch Decrease in carcass = lower intake, less digestible food, decreased protein content
Making Silage • Preserved grass by acids. • Lactic Acid from sugars in grass • Complete absence of air. • Adequate supply of sugars.
Complete Absence of Air • Air must be excluded to enable Lactic Acid Bacteria to feed & prevents rotting. • Lactobacilli • Streptococci • These bacteria feed & multiply to produce LACTIC ACID-Preserve • Anaerobic bacteria • The Faster air is excluded the quicker the bacteria can start to work on sugars to produce acid to lower pH. • Fast filling the pit & sealing is vital • pH 4 as fast as possible
Adequate Supply of Sugars • Anaerobic bacteria feed sugars Acids • Sugar content 10 –15% • Different grass species • Grass acts as a substrate for the bacteria & converts the sugars to acids
Grass Species used for Silage • Perennial Ryegrass • Italian Ryegrass (biennial) • White clover • Red clover
Air free Fill silo quickly Short cut grass Good compaction Wilted grass Lactobacillus Streptococcus Good Acidification Low pH Effective Additive Good Sealing of silo High sugar Grass STAGE of Growth = High Palatability, High Digestibility Factors forming Lactic Acid Silage
Additive • Improve Silage Preservation • Increased Silage Intake • Improved digestibility & animal performance
Molasses • Sugar Based • Added to supplement sugars already present in grass. • The sugars are converted to acids by microbes. • 9-18 litres/ton of grass • Added either by harvester or at the pit • Young leafy grass, wet weather have reduced sugar content
Sulphuric/Formic Acid • These reduce the pH of grass from 6 to 4.8 • Creates an environment which favours lactic acid production • 2-3 litres/ton • The lower the sugar level in grass, the leafier the grass & the wetter the grass the higher rate of acid is used
Silage Cutting • Mower- chops the grass up small to increase the surface area for bacteria to act on • Precision chop mower
Wilting • This is to cut the grass & leave it on the ground for 24 –48 hours before gathering up & ensiling it • To remove some water from the crop • Increases conc. Of sugars • Reduces level of effluent • Raises DM content • Reduces the activity of undesirable bacteria • Reduces the size of clamp required • Saves on additives
To Make silage • Close the field in time. • Fertilize adequately • Cut at the correct stage of growth- precision chopper • Allow to wilt for 1-2 days • Pick up the grass • Transport to pit/bale • Fill pit quickly • Use an additive • Spread grass and compact evenly • Cover & seal the pit
Experiments • % Sugar in silage sample • Compare silage samples-colour, smell, pH, water content. • % DMD • To conserve grass as silage in the lab
To get high levels of carbohydrates • Cut the grass at the young leafy stage • Cut in dry conditions(water dilutes) • Allow to wilt • Cut using a precision chop mower • Use a carbohydrate rich additive • Mow in afternoon