Starts with the soil - Soil analysis

Nutrient management planning

Silage Quality1.Fermentation (pH & Ammonia N)2.Feeding value (D-Value, CP & Dry Matter)

Silage Quantity1.Tonnage required

D-value depends on stage of growth and timing of harvesting

Very high D-value >75High D-value >70Moderate D-value 65-70Low D-value <65

Seed head not visible but moving up the shoot

Seed heads fully emerged and elongated

Grass at 67 D-value

60 D Very stemmy with a dead base

Relationship between silage yield and D-value

0

2

4

6

8

10

12

24-Apr 4-May 14-May 24-May 3-Jun 13-Jun 23-Jun 3-Jul 13-Jul

Date

Yie

ld (

t D

M /

ha

)

60

65

70

75

80

D-v

alu

e

D-value Total DM yield

DM yield of digestible material

67% D

Why? To assess feed value, predicted

animal performance and the need for supplementation

To identify early the stability of the silage and possible impacts on waste and animal health

How? Wait until 6 weeks post harvest Take several cores across clamp

pH of between 3.8 and 4.2 is desirable

In the field after mowing - Respiration occurs breaking down sugars.

Plant proteins are also broken down.

In the silo during filling –sugars are converted to lactic acid in the absence of air until a pH of 3.8 – 4.2 is reached.

In silo – If pH above 4.2 then undesirable bacteria grow converting sugars to butyric acid and protein to ammonia resulting in poor quality silage.

During feed-out – if pH is above 4.2 then sugars in the presence of oxygen are converted to CO2 & heat. Yeasts & moulds also grow rapidly.

1. Sward type – PRG is better

2. Nitrogen Application

3. Stage of growth

4. Weather & Grass Dry Matter

5. Silo filling & sealing technique

Ensure sugar content of grass is high (greater than 2.5% fresh weight) by:

1.Harvesting swards with a high PRG content.

2.Applying slurry & fertiliser at correct rate & time.

3.Harvesting in bright sunny weather.4.Carry out ensilability analysis.

Indicates the potential fermentation quality by giving information on:

1.Dry matter2.Crude protein3.Water soluble carbohydrates (sugars)4.Nitrate5.Buffering Capacity

Rule of thumb – allow a day for every 2 units of Nitrogen to grow out of grass

Hence 3 bags 27%N = 81 units

81 divided by 2 units/day

41 days required between fertiliser application and cutting

Ensure silage dry matter is high by:

1.assessing % DM before harvesting.

2.harvesting grass at and/or wilting to 25 -30% DM.

Spread the herbage over as large an area as possible immediately post mowing

Max wilting period 24-30 hours

Prolonged wilting reduces digestibility

Wilting results in increased silage DM intakes

Can be used as an aid to make good silage but not a remedy for poor management

Inoculants are the main type

1. Inoculants contain one or more lactic acid bacteria and promote efficient fermentation

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 (6 – 9 inches)

Roll continuously

Rapid filling is best

All silage effluent must be collected.

The tank must be checked regularly to ensure that it does not overflow or that it is not leaking.

Empty the tank regularly to prevent effluent reaching drains or watercourses

Same principles apply as with pit silage

Bales should be dense and cylindrical in shape

Wrap as soon as possible after baling

4 - 6 layers of plastic film

Wrap at the stacking area if possible

If not, move bales from the field immediately after wrapping

Oxygen will enter a bale every time it is handled

Avoid spiking if possible at any time (even before wrapping)

Section A:30 x 3 x 10 = 900m3

Plus

Section B:5 x 3 x 10 = 150m3 X 0.5 = 75 m3

Total = 900 + 75 = 975m3

30m 5m

3m

Width of pit = 10m Assume silage is 30% Dry matter

A B

Example:

Conversion FactorsSilage Dry Matter Conversion factor

Measuring Quantity

Silo/Pit:

Length (m) x Width (m) x Height (m)

=

Volume (m3)

X

Dry Matter Conversion factor

=

Tonnes of silage

Measuring Quantity

kg/bale or t/bale

Round (unchopped) 1.3m 500 0.5

Round (chopped) 1.3m 650 0.65

Square (2.5mx1.2mx0.9m) 730 0.73

(8x4x3’)

Will vary enormously with dry matter, sward type and operator!

Silage RequirementsType of stock NoRequirement per month (t)

MonthsSilage

requirement

Spring calver 1.0

250 – 350 kg store

0.8

Calves 0.3

Ewes 0.15

Total silage required

Cut silage around 50% ear emergence to

optimise yield and quality

Allow 2 units N/day from sowing to cutting

Don’t overwilt – 30 hours max

Seal silo carefully

Handle bales carefully

Do a budget before winter

The amount of grass grown depends on many factors

1.Soil temperature (>6° C)2.Light 3.Water4.Nutrient availability5.Grass type/breed

At peak growth there is a new leaf every 4-5 days (May)

Peak growth all 3 leaves replaced in 2-3 weeks

Best time to graze is at 2 ½ to 3 leaves

4 main grazing systems used

1.Set stocking

2.Rotational grazing

3.Strip grazing

4.Paddock grazing

Set stocking Rotational

Paddock grazing

Animals have unrestricted access over a wide area throughout the grazing season

Pros ConsLow management input Lower grass yield

Low capital cost (1 drinking trough, external fence)

Difficult to manage and maintain grass quality and height

Can work well if sward height maintained at correct level

Uneven manure distribution

Lower utilisation due to trampling

Weeds allowed to build up

Animals move around a small number of fields based on sward height or after a certain number of days

Pros ConsHigher production than set stocking

More fencing required

Allows pasture to rest and recover

Extra drinking troughs needed

Can extend the grazing season

Grass production and utilisation not optimum

More even distribution of manure

Animals given a new allocation of grass each day by mean of electric fence

Pros ConsUseful when excess of grass at points in the year

Labour intensive. Fence needs moved each day

Good utilisation of grass – very little trampling or spoiling of grass

Water availability a problem

Very good for forage crops like kale and rape

Not ideal as cattle are usually allowed back over previous days grazings

Hampers re-growth

Can lead to trampling along fence line

Animals are moved frequently through a series of paddocks based on measured grass heights or grass covers

Pros ConsHighest grass production and use

Initial cost of fencing and water troughs

High quality grass & higher stocking rates

More intensive management – skill required

More even manure distribution

Requires careful monitoring

Can extend grazing season

Allows for excess grass to be cut out as silage (bales)

Quieter/more manageable stock?

System Annual Yield

(t DM/ha)

Utilisation

(%)

Usable yield

(t DM/ha)

% increase

Set stocking

8.5 50 4.3  

Rotational

10.2 65 6.6 56%

Paddock 10.2 80 8.2 92%

To be continued!