Level II Agricultural Business Operations

Good quality silage is a key factor in

profitable milk production

Silage Production

Silage Assessment

Dry Matter (DM)

Metabolisable Energy (ME)

Crude Protein (CP)

Fermentation (acidity level pH and

ammonia level NH3)

Dry Matter is the feed remaining after all the

water has been taken out

Dependent on weather and degree of wilting

Ideally 25-30%

Grass wilted over 30 % is more difficult to

consolidate

More prone to spoilage by yeasts and moulds

ME measures the energy content of silage in MJ/kg DM

Very high >12 High 11.5 – 11.9Moderate 10.5 – 11.4Low <10.5

CP measures the protein content of silage as a percentage of DM

Very high 14% High 12 –14%Moderate 10 –12%Low <10%

pH of between 3.8 and 4.2

Ammonia (% of total Nitrogen) less than 10

is desirable

Good fermentation is needed to ensure the

stable conversion of ensiled grass to silage

Poor fermentation produces silage

unpalatable to stock

1. Sward type

2. Nitrogen application

3. Stage of growth

4. Weather & grass DM

5. Chop length

6. Additives

7. Silo filling & sealing technique

Perennial Ryegrass swards will produce better

quality and higher D-value silage than old swards

Heading date of grasses in sward will have effect

on quality and D-value (early/intermediate/late)

Newly reseeded swards generally produce higher

quality silage

Rule of thumb – allow a day for every

1kg/day (2 units) of N to grow out of grass

Allow for both slurry and fertiliser N

Grass analysis indicates the potential

ensilability and fermentation of crop

Yield increases rapidly from mid April to late June

Quality decreases rapidly from mid May to mid June

The stage of growth at which crop is cut will have more influence on feeding value of silage than any other factor under the farmers control

3. Stage of GrowthHigh ME Silage

3. Stage of GrowthLow ME Silage

High DM silage is weather dependent

Aim to harvest at 25 – 30 % DM

Rapid wilting preferable (24-30 hours)

Reduces effluent

High DM (>30% DM) is better chopped short

– approx 25mm (1 inch) – allows for better

consolidation

Lower DM (<25% DM) is better with longer

chop length – 50 mm (2 inches) or above

Aid to make good silage

Inoculants are the main type

◦Inoculants contain one or more lactic acid

bacteria and promote efficient fermentation

Acid additives no longer commonly used

50mm drainage pipe

600mm

125 mm

Grass placed on top by hand

0.125mm polythene

Clean pit thoroughly

Hang plastic side sheet to ensure good seal

Spread grass over pit evenly in shallow layers 150 – 225 mm (6 – 9 inches)

Roll continuously

Rapid filling is best

Silage effluent is highly pollutant and must

be collected

If stored with cattle slurry, extreme care

must be taken when mixing due to

increased risk of gaseous emissions

Tanks must be checked regularly to

prevent overflow and leakage

Same principles apply as with pit silage

Bales should be dense and compact

Wrap as soon as possible after baling

4 - 6 layers of plastic film

Wrap at the stacking area if possible

Avoid excessive handling

Store bales immediately after wrapping

Storage in line with NIEA regulations

◦Effluent must be collected from bales

stored on concrete etc.

Protect against vermin damage

Calculating available silage is the first

step in winter feed planning

◦Assess silage in store

◦Assess silage required

◦Carry out a balance

1. Silo length

2. Silo width

3. Average silo height

4. Calculate volume

(length x width x height)

10.6 m 3.3 m22.8m

Volume = 10.6 X 3.3 X 22.8

798 cubic metres (@ 20%DM)

 Silage Dry Matter

Silage Density Multiply volume

by

Grass silage 18% 0.81

20% 0.77

25% 0.68

30% 0.60

10.6 m 3.3 m22.8m

Volume = 10.6 X 3.3 X 22.8

798 cubic metres

798 X 0.77 = 614 t

Pit Length Width Height

1st 22.8 10.6 3.3

2nd 18.9 9.1 2.1

Volume

798

361

Factor

0.77

0.77

Total

Tonne

614

278

892

Animal No.

Silage required (t/cow/mth)

No mths

Total (t)

Milk cow 60 1.5 6 540

Dry cow 20 1.2 6 144

In Calf 10 1.2 6 72

Maiden 1 6Total

required (t)

756

Assess silage available against silage required

Available silage = 892 tonnesRequired silage = 756 tonnes

In this example 136 t of silage is surplus to requirement

Aim to make high quality silage

Ensure correct fertiliser application

Consider grass analysis pre-cutting

Choose suitable cutting stage and weather

Consider rapid wilt

Collect and handle effluent safely

Calculate quantity of silage