Developed by IGER (Institute Grassland Environmental Research) in
cooperation with Dow – the manufacturer of DOWLEX™ Polyethylene
Resins used in leading brands of stretch film wrap – this guide offers
a practical farm-specific assessment on how farmers can measure
and reduce their on-farm losses throughout the silage making process.
Assessing On-Farm Dry Matter Losses in Silage Making
A key factor affecting the cost of silage production is the dry matter
(DM) losses associated with silage making and feeding. Silage
making is prone to high DM losses and these have been shown to
average 25%, but for grass silage these can range from 10% to 70%,
representing a cost to European farmers estimated at € 3.1 billion.
Baled silage is generally best – with losses of just 8% compared to
clamp silage losses, which are often as high as 25%. So by knowing
where on-farm losses occur and understanding how to reduce them,
farmers can significantly reduce their silage production costs and thus
improve their financial profi tability.
Losses can occur at every stage of the process of making silage, from the point
of cutting the forage in the field to the point of consumption by the animal during
feed-out. The four key stages where losses occur with their ranges are shown in
figure 1.
Figure 1 – Potential DM losses during silage making stages
30
25
20
25
%
15
18
10
12
8
5
5
0
2
In Field-Harvesting
1
0
In Silo-Respiration
and Fermentation
Effluent
Feed-out-Aerobic
deterioration
Source: IGER
The first step for farmers to be able to adjust their silage making systems in order to
help reduce their losses is to know what those losses are. This is a relatively easy
but potential time-consuming task to carry out.
Two approaches that can be used:
1. The simple method, which compares the estimate of the DM yield of forage
at cutting time and with an estimate of total silage DM at feeding time. The
difference in DM yield between these will give the total DM loss during the
ensilage process.
2. The complete method, which takes DM and total yield measurements at
different points along the ensilaging process: at cutting, at baling/clamping,
effluent losses, at opening the bale/clamp, at feed-out. This approach
requires more effort but will offer a better understanding of where your
greatest losses occur and so where your efforts should be focused in order to
reduce them.
For the purpose of this guide, we look at how you can assess the losses using
the second, complete approach. The evaluation using the simple method can be
carried out by following the first and last steps.
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STAGE 1
Measuring In-Field/Harvesting Losses
(Typical range of losses: 2 – 12%)
At or immediately prior to mowing
Step 1
Take a sample of fresh forage from a 1 metre squared area
of land, cut all the forage from the area at the same height
as the mower.
Step 2
Preferably repeat this at least six times.
Step 3
Weigh the sample (Fresh Matter).
Step 4
Fresh Matter of sample gives the Fresh Matter yield per 1 m 2 .
Step 5
Dry the sample (Dry Matter).
Step 6
Weigh again.
Step 7
Dry Matter of sample gives the Dry Matter yield per 1 m 2 .
Step 8
Multiply DM yield by 10,000, to give yield per hectare.
Result
Multiply DM yield per hectare by total number of hectares
to give total farm silage DM yield.
(Answer 1 – see page 7)
Explanation
At the time when the forage is cut, a sample
of fresh forage from a known area is required
(either immediately prior to or immediately post
cutting). Ideally this should be carried out at a
number of places across a field or farm. This
sample will help to enable the calculation of a
fresh matter forage yield per hectare by taking
the fresh weight (kg) per square metre and
calculating up to total forage area. The fresh
sample should then be dried until the weight of
the remaining sample does not change. This can
be done in either an oven at 60 – 80°C for 24 to
36 hours or carefully in a microwave by heating
for 1 minute intervals with the fresh forage but
reducing incrementally to 10 seconds whilst the
forage becomes drier. Care needs to be taken to
ensure that when the forage is becoming close
to dry that the forage does not burst into flames
when using the microwave method. This will
enable a DM yield to be calculated either on a
hectare basis or whole farm silage area basis.
At feed-out every load of silage removed from
the silage clamp needs to be weighed alongside
to any silage rejected either by the animals
or prior to feeding due to low quality. A DM
content either obtained from a silage sample
analysed for chemical composition or by the
method above needs to be determined on the
silage such that a total DM of silage actually
eaten can be determined. The difference
between the total DM yield of the fresh forage
in the field and that of the total DM of silage
eaten offers the value of the DM of silage lost
in the whole process.
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Immediately prior to baling or
forage harvesting
Method for Clamp/ Pit / Bunker
Silage System
Method for Bale System
Step 1 Weigh a representative number of
loads into the silo and take a fresh
sample.
Step 1 Weigh a representative number of
bales immediately prior to wrapping
and take a fresh sample.
Step 2 Count the number of loads.
Step 2 Count the number of bales.
Step 3 Bulk up the fresh samples collected
and mix well.
Step 3 Bulk up the fresh samples collected
and mix well.
Step 4 Take a sample from the mixed bulked
sample, weigh (Fresh Matter) and dry.
Step 4 Take a sample from the mixed bulked
sample, weigh (Fresh matter) and dry.
Step 5 Weigh Dry sample (Dry Matter).
Step 5 Weigh dry sample (Dry Matter).
Step 6 Calculate the total harvest Dry Matter
yield – multiply DM per load by number
of loads.
Step 6 Calculate the total harvest Dry Matter
yield – multiply DM per bale by number
of bales.
Step 7 Divide the total DM yield by the
number of hectares harvested, this
gives DM yield per hectare.
Step 7 Divide the total DM yield by the
number of hectares harvested, this
gives DM yield per hectare.
Result The difference between the DM yield
of sample at cutting and harvesting
gives the DM loss per hectare.
Result The difference between the DM yield
of sample at cutting and harvesting
gives the DM loss per hectare.
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STAGE 2
Measuring In-Silo Losses
(Typical range of losses from 5 – 18%)
The process is more difficult to perform with a clamp/bunker/
pit silage system than a bale system. Although with the advent
of total mixed rations and the increased use of forage wagons,
a daily figure of silage used can be easily ascertained from the
forage wagon.
Method for Clamp/ Pit / Bunker
Silage System
Method for Bale System
Step 1 Weigh a representative number of
loads taken from the silo, preferably
one load per week or fortnight.
Step 1 Weigh a representative number of
bales immediately after opening the
bale prior to feeding. Preferably these
should be the same bales weighed
at the start of the storage phase,
and the differences within that bale
calculated.
Step 2 Take a fresh sample (Fresh Matter).
Step 2 Take a fresh sample (Fresh Matter).
Step 3 Count the total number of loads taken
over the feeding period.
Step 3 Count the number of bales.
Step 4 Weigh the Fresh Matter and dry it.
Step 4 Weigh the Fresh Matter and dry it.
Step 5 Weigh the dry sample (Dry Matter).
Step 5 Weigh dry sample (Dry Matter).
Step 6 Calculate the total harvest silage DM
removed from the silage clamp –
multiply DM per load by number of loads.
Step 6 Calculate the total silage DM yield –
multiply DM per bale by the number
of bales.
Step 7 Divide the total silage DM yield by the
number of hectares harvested, this
gives silage DM yield per hectare.
Step 7 Divide the total silage DM yield by the
number of hectares harvested, this
gives silage DM yield per hectare.
Result The difference between the DM yield
at the start of ensilage and the silage
DM yield removed from the clamp
gives the total in-silo DM losses.
Result The difference between the DM yield
at the start of ensilage and the silage
DM yield removed from the bales gives
the total in-silo DM losses.
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STAGE 3
Measuring Effluent Losses
(Typical range of losses from 0 – 8%)
Effluent losses for the clamp system are relatively easy to
measure. They are typically easy to measure from bales if the
effluent is collected, or they are difficult to measure.
Step 1
Measure total volume of effluent released from silage
during storage.
Step 2
Take a known volume of effluent for example 1 litre.
Step 3
Weigh the fresh sample (Fresh Matter).
Step 4
Dry the sample (Dry Matter).
Result
Dry weight of sample per litre multiplied by the total number
of litres gives the total effluent DM loss.
Note:
It is important to note that effluent losses
will also be calculated as part of the in-silo
losses and so need not be included in the final
summation of total losses at the end of the
process.
It is worth remembering that by wilting silage
to 28% DM, the production of effluent can be
completely removed. This will not only reduce
the DM losses but will reduce the environmental
problems related to effluent production not
properly collected and that could result in crosscompliance issues, which will affect future
European Union subsidy income.
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STAGE 4
Measuring Feed-Out/Aerobic Deterioration Losses
(Typical range of losses from 1 – 25%)
The assessment of feed-out aerobic deterioration losses is a
key part of the overall assessment of total losses. Any mouldy
or poorly fermented silage not fed to stock is weighed as is any
silage rejected by the stock at feed-out.
Step 1
Silage rejected by the farmer prior to feeding is weighed.
Step 2
Sample taken and weighed.
Step 3
Sample dried and weighed.
Step 4
Total Dry Matter (DM) of silage rejected by farmer is
calculated.
Step 5
Silage rejected by stock is weighed.
Step 6
Sample taken and weighed.
Step 7
Sample dried and weighed.
Step 8
Total DM of silage rejected by farmer is calculated.
Step 9
Total DM of silage rejected by farmer and stock is added
together.
Step 10 Total DM of silage actually fed to stock minus total silage
DM rejected by stock gives the silage DM available to
animals for utilisation for growth and production.
(Answer 2 – see below)
Result
The difference between the silage DM yield removed from
the clamp or bale and the total DM rejected at feed-out
either by the farmer or stock gives the feed-out DM losses.
Measuring Losses from
Harvest to Feeding
Result
By taking Answer 1 and subtracting Answer 2, the total DM
losses from harvest to feeding can be calculated.
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Conclusions
Whilst this may seem like a laborious process, the assessment of YOUR potential
losses can help YOU to make improvements that can help save costs.
A few pointers to help reduce losses are:
•
Rapid filed wilting, no more than 24 hours for grass and 48 hours for legumes
such as lucerne and red clover.
•
Spread the forage in as wide a swath as possible as quickly as possible and
definitely within 1 hour of cutting.
•
Add an additive to control the fermentation and reduce in-silo losses.
•
Compact and seal either the clamp or bale well and quickly. Use six layers of
quality silage wrap film on the bale.
•
Maintain the silage storage area to reduce damage to bales and clamp and so
reduce the risk of air (oxygen gaining access to the silage).
•
Consider a good way to feed the silage to minimise wastage either through
aerobic spoilage or by the animals during feeding.
You can get more tips on silage production at www.dowsilage.com.
The information and data hereabove are given in good faith. No liability, warranty or guarantee is assumed by The Dow
Chemical Company.
DOWLEX™ polyethylene resins, designed and adapted for bale wrapping films, are made of low density linear
polyethylene.
For more information on Dow and its activities in the silage market, visit www.dowsilage.com
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