UGANDA STANDARD  
      US ISO 6496
First Edition
   2009 -09-04
 
Reference numbe r 
   US ISO 6496:1999
 © UNBS 200 9 
  
Animal feeding stuffs — Determination of moisture and other 
volatile matter content 
 US ISO 6496:1999  
 
© UNBS  2009 – All rights reserved Compliance with this standard does not, of itself confer immunity from legal obligations 
A Uganda Standard does not purport to include all necessary provisions of a contract. Users are 
responsible for its correct application  
© UNBS 2009 
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilised in any 
form or by any means, electronic or mechanical, in cluding photocopying and microfilm, without prior written 
permission from UNBS. 
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The Executive Director 
Uganda National Bureau of Standards 
P.O. Box 6329 
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Uganda 
Tel: 256 41 505 995 
Fax: 256 41 286 123 
E-mail: unbs@infocom.co.ug
     US ISO 6496:1999  
© UNBS  2009 - All rights reserved National foreword 
Uganda National Bureau of Standards (UNBS) is a parastatal under the Ministry  of Tourism, Trade and 
Industry established by the Act of Parliament of 198 3, of the Laws of Uganda.  UNBS is mandated to co-
ordinate the elaboration of standards and is  
(a) a member of International Organisation for Standardisation (ISO) and  
(b) a contact point for the WHO/FAO Codex A limentarius Commission on Food Standards, and  
(c) the National Enquiry Point on TBT/SPS Agr eements of the World Trade Organisation (WTO). 
The work of preparing Uganda Standards is carried out through Technical Committees. A Technical 
Committee is established to deliberate on standards in a gi ven field or area and consists of representatives of 
consumers, traders, academician s, manufacturers, governme nt and other stakeholders. 
Draft Uganda Standards adopted by the Technical Committ ee are widely circulated to stakeholders and the 
general public for comments. The committee reviews the comments before recommending the draft standards 
for approval and declaration as Uganda Standards by the National Standards Council. 
This Uganda Standard, US ISO 6496:1999,  Animal feeding stuffs — Determination of moisture and other 
volatile matter content, is identical with and  has been reproduced from an International Standard ISO 6496:
1999, Animal feeding stuffs —Determination of moisture and other volatile matter content, and has been
adopted  as a Uganda Standard. 
Wherever the words, "International Standard" a ppear, they should be replaced by "Uganda Standard." A Reference numbe r
ISO 6496:1999 (E)INTERNATIONAL
STANDARDISO
6496
Second edition
1999-08-01
Animal feeding stuffs — Determination of
moisture and other volatile matter content
Aliments des animaux — Détermination de la teneur en eau et en d'autres
matières volatilesISO 6496:1999(E)
©   ISO 1999
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by an y means, electronic
or mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case postale 56 • CH-1211 Genève 20 • Switzerland
Internet iso@iso.ch
Printed in Switzerland
iiForeword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO
member bodies). The work of preparing International Standards is normally carried out through ISO technicalcommittees. Each member body interested in a subject for which a technical committee has been established hasthe right to be represented on that committee. International organizations, governmental and non-governmental, inliaison with ISO, also take part in the work. ISO collaborates closely with the International ElectrotechnicalCommission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.Draft International Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.
International Standard ISO 6496 was prepared by Technical Committee ISO/TC 34, 
Agricultural food products ,
Subcommittee SC 10, Animal feeding stuffs .
This second edition replaces the first edition (ISO 6496:1983), which has been technically revised.Annex A of this International Standard is for information only.INTERNATIONAL STANDARD    © ISO ISO 6496:1999(E)
1Animal feeding stuffs — Determination of moisture and other
volatile matter content
1 Scope
This International Standard specifies a method for the determination of the moisture and other volatile matter
content of animal feeding stuffs.
The method is applicable to animal feeding stuffs with the exception of:a) milk products;b) mineral substances;c) mixtures containing a considerable amount of milk products or mineral substances, for example milk replacers;d) animal feeding stuffs containing humectants (e.g. propylene glycol);e) the following simple animal feeding stuffs:
¾ animal and vegetable fats and oils (for which method A specified in ISO 662 [1] is applicable);
¾ oilseeds (for which a method is specified in ISO 665 [2]);
¾ oilseed residues (for which a method is specified in ISO 771 [3]);
¾ cereals, except maize, and cereal products (for which a method is specified in ISO 712 [4]);
¾ maize (for which the reference method specified in ISO 6540 [5] is applicable).
2 Normative reference
The following normative document contains provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, such publications donot apply. However, parties to agreements based on this International Standard are encouraged to investigate thepossibility of applying the most recent edition of the normative document indicated below. For undated references,the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers ofcurrently valid International Standards.
ISO 6498, 
Animal feeding stuffs — Preparation of test samples.
3 Term and definition
For the purposes of this International Standard, the following term and definition apply.
3.1
moisture and other volatile matter content
mass fraction of substances lost on drying the sample by the procedure specified in this International StandardISO 6496:1999(E) © ISO
2NOTE  The moisture and other volatile matter content is expressed as a mass fraction in percent [formerly given as
% (m/m)].
4 Principle
The loss of mass of a test portion of the sample on drying is determined under specified conditions depending on
the nature of the sample.
5 Apparatus and materials
Usual laboratory apparatus and materials and, in particular, the following.
5.1   Analytical balance , capable of weighing to the nearest 1 mg.
5.2   Container , of non-corrodible metal or glass, provided with a sufficiently tight-fitting lid, and having a surface
allowing the test portion to be spread to about 0,3 g/cm2.
5.3   Electrically heated oven , well ventilated, capable of being maintained at a temperature of 103 °C ± 2 °C.
5.4   Electrically heated vacuum oven , capable of being maintained at a temperature of 80 °C ±  2 °C, and
capable of producing a pressure below 13 kPa.
It shall be provided with a thermostat and vacuum pump, and either a device for the introduction of dried air, or a
device containing calcium oxide (CaO) as desiccant (300 g CaO for 20 samples).
5.5   Desiccator , provided with an efficient desiccant.
5.6   Sand, acid-washed.
6 Sampling
Sampling is not part of the method specified in this International Standard. A recommended sampling method is
given in ISO 6497 [6].
It is important that the laboratory receive a sample which is truly representative and has not been damaged or
changed during transport or storage.
Store the sample in such a way that deterioration and change in composition are minimized.
7 Preparation of test sample
Prepare the test sample in accordance with ISO 6498.
8 Procedure
8.1 Test portion
8.1.1 Feeding stuffs in liquid or paste form, and feeding stuffs predominantly composed of oils and fats
Place a thin layer of sand (5.6) and a glass rod into a container (5.2). Dry the container with its contents and lid in
the oven (5.3) set at 103 °C for 30 min ± 1 min. Place the lid on the container, remove from the oven and allow to
cool to ambient temperature in the desiccator (5.5). Weigh the container with its contents and lid to the nearest1 mg.© ISO ISO 6496:1999(E)
3Into the container, weigh, to the nearest 1 mg, about 10 g of the prepared test sample (clause 7). Using the glass
rod, mix thoroughly with the sand. Leave the glass rod in the container. Proceed in accordance with 8.2.
8.1.2 Other feeding stuffs
Dry a container (5.2) with its lid in the oven (5.3) set at 103 °C for 30 min ± 1 min. Remove from the oven and allow
to cool to ambient temperature in the desiccator (5.5). Weigh the container with its lid to the nearest 1 mg.
Into the container, weigh, to the nearest 1 mg, about 5 g of the prepared test sample (clause 7) and spread evenly.
8.2 Determination
Place the container, with its lid beneath or beside it, in the oven (5.3) set at 103 °C. It is recommended that not more
than one container per litre of oven volume be placed in the oven.
Leave to dry for 4 h ± 0,1 h after the oven temperature has returned to 103 °C . Place the lid on the container,
remove from the oven, allow to cool to ambient temperature in the desiccator (5.5) and weigh to the nearest 1 mg.
Feeding stuffs consisting mainly of oils or fats shall be dried for another 30 min ± 1 min in the oven (5.3) set at
103 °C. The change in mass between the two weighings shall not exceed 0,1 % of the mass of the test portion. Ifthe change in mass is more than 0,1 % of the mass of the test portion, discard the result and repeat the procedure.If the change in mass is again more than 0,1 % of the mass of the test portion, proceed in accordance with 8.3.
8.3 Check test
In order to check whether during drying of the test portion an unacceptable change in mass occurs as a result ofchemical reactions (for example Maillard reactions), proceed as follows.
Dry the container and test portion again in the oven (5.3) set at 103 °C for 2 h ± 0,1 h. Allow to cool to ambient
temperature in the desiccator (5.5) and weigh to the nearest 1 mg. If the change in mass during this second dryingperiod is more than 0,2 % of the mass of the test portion, chemical reactions may have occurred. In this case,discard the result and apply the procedure specified in 8.4.
NOTE  The criterion of 0,2 % of the mass of the test portion should not be confused with the repeatability limit of
0,2 % defined in 10.2. The latter concerns the absolute difference between two independent single test results obtained underrepeatability conditions. The former is based on the difference between two weighings of the same test portion before and afteran extra period of heating in order to check whether an unacceptable change in mass has occurred.
8.4 Samples giving unacceptable change in mass
Take the test portion in accordance with 8.1.
Place the container, with its lid beneath or beside it, in the vacuum oven (5.4) set at 80 °C. Reduce the pressure to
about 13 kPa and dry the sample at this pressure, either while admitting dried air, or in the presence of thedesiccant (see 5.4). In the latter case, disconnect the vacuum pump after the specified pressure has been reachedand ensure that this pressure is maintained throughout the drying period. Heat the sample for 4 h ± 0,1 h after the
oven temperature has returned to 80 °C. Return the oven pressure carefully to atmospheric pressure. Open theoven, immediately place the lid on the container, remove from the oven, allow to cool to ambient temperature in thedesiccator (5.5) and weigh to the nearest 1 mg.
Dry for additional periods of 30 min ± 1 min in the vacuum oven set at 80 °C and weigh until the change in mass
between two consecutive weighings does not exceed 0,2 % of the mass of the test portion.
8.5 Number of determinations
Carry out two determinations on test portions taken from the same test sample.ISO 6496:1999(E) © ISO
49 Expression of results
9.1 Determination without preliminary conditioning
Calculate the moisture and other volatile matter content of the test sample, w1, in percent, by the equation:
()w mm m
m135 4
3100 =--·%
where
m3is the mass, in grams, of the test portion;
m4is the mass, in grams, of the container with lid including, if appropriate, sand and glass rod;
m5is the mass, in grams, of the container with lid and dried test portion including, if appropriate, sand and
glass rod.
9.2 Determination with preliminary  conditioning
NOTE  For samples which are difficult to crush, see ISO 6498.
9.2.1 Samples with moisture content more than 17 % and fat content less than 120 g/kg, which need only
preliminary drying
Calculate the moisture and other volatile matter content of the test sample, w2, in percent, by the equation:
()wmm
mmm m
mm
m201
035 4
31
0100 =-+--
·æ
Łççö
ł÷÷Ø
ºŒ
Œø
ßœ
œ·%
where
m0is the mass, in grams, of the test sample;
m1is the mass, in grams, of the test sample after extraction and/or drying and conditioning in ambient air;
m3is the mass, in grams, of the test portion;
m4is the mass, in grams, of the container with lid including, if appropriate, sand and glass rod;
m5is the mass, in grams, of the container with lid and dried test portion including, if appropriate, sand and
glass rod.
9.2.2 Samples with high fat content and low moisture content, which need only preliminary defatting, and
samples with high fat content and high moisture content, which need preliminary drying followed bypreliminary defatting
Calculate the moisture and other volatile matter content of the test sample, w
3, in percent, by the equation:
()wmmm
mmm m
mm
m3012
035 4
31
0100 =--+--
·æ
Łççö
ł÷÷Ø
ºŒ
Œø
ßœ
œ·%
where m2 is the mass, in grams, of the fat extracted from the test sample (see ISO 6498).
For the explanation of the other symbols, see 9.2.1.© ISO ISO 6496:1999(E)
59.3 Results
Take as the result the arithmetic mean of the two intermediate test results (8.5), provided that the absolute
difference between the two results does not exceed 0,2 %. Repeat the procedure if the difference exceeds 0,2 %.
Express the result to the nearest 0,1 %.
10 Precision
10.1 Interlaboratory test
Details of an interlaboratory test on the precision of the method are summarized in annex A. The values derived
from this interlaboratory test may not be applicable to concentration ranges and matrices others than those given.
10.2 Repeatability
The absolute difference between two independent single test results, obtained using the same method on identicaltest material in the same laboratory by the same operator using the same equipment within a short interval of time,will in not more than 5 % of cases exceed the repeatability limit r given in or derived from Table 1.
Table 1 — Repeatability limit (r) and reproducibility limit (R)
Sample Moisture and other
volatile contentrR
%% %
Mixed feed 11,43 0,71 1,99
Mixed feed concentrate 10,20 0,55 1,57
Molassed feed 7,92 1,49 2,46
Dried grass 11,77 0,78 3,00
Beet pulp 86,05 0,95 3,50
Alfalfa (lucerne) 80,30 1,27 2,91
10.3 Reproducibility
The absolute difference between two single test results, obtained using the same method on identical test material
in different laboratories with different operators using different equipment, will in not more than 5 % of cases exceedthe reproducibility limit R given in or derived from Table 1.
11 Test report
The test report shall specify:
¾ all information necessary for the complete identification of the sample;
¾ the sampling method used, if known;
¾ the test method used, with reference to this International Standard;
¾ all operating details not specified in this International Standard, or regarded as optional, together with details of
any incidents which may have influenced the test result(s);
¾ the test result obtained, or the two test results obtained if the repeatability has been checked.ISO 6496:1999(E) © ISO
6Annex A
(informative)
Results of interlaboratory test
An interlaboratory test was organized by ISO/TC 34/SC 10, Animal feeding stuffs , in 1996 and carried out in
accordance with ISO 5725-2:1994 [8]. In the test 23 laboratories participated. Samples of mixed feed, mixed feedconcentrate, molassed feed, dried grass, beet pulp and alfalfa (lucerne) were investigated.
Table A.1 — Statistical results of the interlaboratory test
Parameter Samplea
123456
Number of laboratories retained after eliminating
outliers23 23 19 23 23 23
Mean moisture and other volatile matter
content, % 11,43 10,20 7,92 11,77 86,05 80,30
Repeatability standard deviation, sr, % 0,253 0,195 0,533 0,28 0,34 0,454
Repeatability coefficient of variation, % 2,21 1,91 6,73 2,38 0,40 0,57
Repeatability limit r   (2,8 ´ sr), % 0,71 0,55 1,49 0,78 0,95 1,27
Reproducibility standard deviation, sR, % 0,71 0,562 0,878 1,07 1,25 1,04
Reproducibility coefficient of variation, % 6,22 5,51 11,09 9,09 1,45 1,30
Reproducibility limit, R  (2,8 ´ sR), % 1,99 1,57 2,46 3,00 3,50 2,91
aSample 1: mixed feed;
Sample 2: mixed feed concentrate;Sample 3: molassed feed;Sample 4: dried grass;Sample 5: beet pulp;Sample 6: alfalfa (lucerne).© ISO ISO 6496:1999(E)
7Bibliography
[1] ISO 662, Animal and vegetable fats and oils — Determination of moisture and volatile matter content.
[2] ISO 665, Oilseeds — Determination of moisture and volatile matter content.
[3] ISO 771, Oilseed residues — Determination of moisture and volatile matter content.
[4] ISO 712, Cereals and cereal products — Determination of moisture content (Routine reference method).
[5] ISO 6540, Maize — Determination of moisture content (on milled grains and on whole grains).
[6] ISO 6497, Animal feeding stuffs — Sampling.
[7] ISO 5725-1:1994, Accuracy (trueness and precision) of measurement methods and results — Part 1: General
principles and definitions.
[8] ISO 5725-2:1994, Accuracy (trueness and precision) of measurement methods and results — Part 2: Basic
method for the determination of repeatability and reproducibility of a standard measurement method.ISO 6496:1999(E) © ISO
ICS  65.120
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