1. Principle
Dry matter is determined gravimetrically as the residue remaining after drying at 103 ºC in
a ventilated oven.
2. Scope
This procedure is applicable for determination of dry matter in feed ingredients, feeds and
partially-dried (85% dry matter) forages with low volatile acid content. For whole grain,
silage and high sugar feeds, use different procedure
3. Responsibilities
Laboratory Analysts shall perform the analysis as per this method. It is the responsibility
of the Laboratory Analyst to ensure that all conditions laid down in the method are met
and strictly adhered to. Any deviations from the prescribed method shall be recorded and
supervisor notified
4. Equipment
4.1 Aluminium dish (pan), approximately 50 mm diameter, 40 mm deep, covered.
4.2 Analytical electronic balance, accurate to 0.1 mg.
4.3 Forced-air drying oven at 103 ± 2 °C. Oven should be equipped with a shelf to allow
the circulation of air. It should be operated with open vents.
4.4 Desiccator.
5. Reagents
None.
6. Procedure
6.1 Dry aluminium dish (4.1) with cover at 103 ± 2 °C for at least 2 hours.
6.2 Cover dishes and move to a desiccator (4.4).
6.3 Immediately cover desiccator and allow covered dishes to cool to room temperature.
Do not allow dishes to remain in the desiccator for more than 2 hours.
6.4 Weigh dishes with cover (W1) to nearest 0.1 mg, removing one at a time from the
desiccator and keeping the desiccator closed between dish removals. Use tongs to
handle beakers.
6.5 Add approximately 2 g ground sample to each dish. Record weight of dish with cover
and sample (W2) to the nearest 0.1 mg.
6.6 Shake dish gently to uniformly distribute the sample and expose the maximum area
for drying.
6.7 Insert samples (with lids removed to the side) into a preheated oven at 103 ± 2 °C
(4.3) and dry for at least 2 hours, start timing once oven has reached temperature (dry
to constant weight, may need to check this for various sample types, once confirmed
use that drying time).
6.8 Move samples to a desiccator (4.4), place cover on each dish, seal the desiccator and
allow to cool to room temperature. Do not allow samples to remain in the desiccator
for more than 2 hours.
6.9 Weigh dish with cover and dried sample (W3), recording weight to nearest 0.1 mg.
7. Calculation
Percent Dry Matter (% DM):
% DM = (W3 – W1) x 100 / (W2 – W1)
where,
W1 = weight of empty dish (g),
W2 = weight of dish and sample (g), and
W3 = weight of dish and sample after drying (g).
Mehmood Hassan
22-cuvas-160
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Kashif Aziz
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Abdul Saboor
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Thanks
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Sameer Murtaza
Poultry Science
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Sameer
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Sameer Murtaza
Muhammad FAHAD
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Abdullah Razzaq
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Turab ul Haq
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Hassam Khalid
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Other formula which is easier may be used:
(W3 – W1)/W2 × 100
W1= weight of crucible
W2= weight of Sample
W3= weight of sample dried + crucible
24-cuvas-0087
24-CUVAS-0085