Slide 1

Silage- Preserved

Grass for Winter

Feed

Factors That Affect Silage Quality

Use of additives Compaction Speed of filling &

sealing the pit Wetness when cut Time of year

ensiled

Silage DataHarvest Date

15 May 29 May

13 June

27 June

Silage Yield 4.0 5.2 6.6 7.8

Silage Digestibility

75 70 65 60

Silage Intake

9.0 8.3 7.6 7.0

Carcass Gain

0.51 0.39 0.27 0.15

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

Factors forming Lactic Acid Silage

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

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 silage1. Close the field in time.2. Fertilize adequately3. Cut at the correct stage of growth- precision chopper4. Allow to wilt for 1-2 days5. Pick up the grass6. Transport to pit/bale7. Fill pit quickly8. Use an additive9. Spread grass and compact evenly10. 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

Veronica Walsh, Coláiste Treasa

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