Silage Advice

How do I calculate how much silage is in store?

Clamps

Use our Clamp Stock Levels Tool

Silage clamp precast concrete walls (1)

1. Calculate the average DM of silage in the clamp as follows:

  • Take several cores representing the whole clamp
  • Mix the cores together very thoroughly on a clean, dry poly sheet then sub-sample.
  • Weigh a suitable dish and measure exactly 100g of forage into it. Note the total weight. Repeat for 3 separate silage samples.
  • Dry the sample down using a microwave oven or put it in a 60oC oven for 24 -48 hours (eg the warming oven of an Aga). 
  • Weigh the dish + dry sample
  • Calculate the DM for each sample then average them.

%DM = (dish + dry sample) – empty dish

2. Use the silage DM and silage DM density from the tables below to tell you how much fresh silage or silage DM you would have in 1 square metre of clamp space.

3. Calculate how many metres cubes (m3) of silage you have in your clamp based on the width, length and height, eg 20m x 50m x 3m = 3,000 m3, eg
From the table, a 30% DM grass clamp with a 3m high face would contain 205 kg (0.205 tonnes) of silage DM per m3 of clamp space.
 
4. Calculate how much you have in the whole clamp (3,000 m3) = 900 x 0.205 = 615 tonnes of silage DM.

Depth of clamp (m)

Grass (kg/m³)
% DM
      Depth of clamp (m)
2 3 4
DM FW DM FW DM FW
20 156 778 176 881 191 954
25 172 690 193 773 208 831
30 186 620 207 689 221 738
35 198 565 218 624 233 666

Grass

Maize (kg/m³)
% DM Depth of clamp (m)
1.5 2 2.5
DM FW DM FW DM FW
25 185 730 195 770 200 800
30 205 680 215 720 225 750
35 215 620 230 660 245 700


Maize

Bales

For bales, weigh a few or estimate their weight then calculate your total fresh silage stocks. Do an oven DM on samples from several bales then calculate DM stocks as follow:
 
Tonnes DM = Tonnes FW x % DM ÷ 100

*DM – dry matter; FW – fresh weight

Fermented wholecrop cereal silage of 50% DM will have a freshweight density of about 600kg/m3 (200kgDM/m3).

Are you a farmer making grass or maize silage?

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