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| Programme 2: Feed Assessment and Monitoring
Programme (FAMP) |
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Features: |
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Mixer Performance Studies |
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| Modern premix and feed mill
mixing equipment are capable of producing a very homogeneous feed product, with
as little as two to three minutes mixing time. Proper mixing is essential in
ensuring uniform distribution of ingredients added to the feed, which directly
influences the animal performance. However, proper mixer performance is
dependent on a number of factors, which include: |
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| Measurement of Mixer Performance |
To ensure the
mixing efficiency, CV (coefficient of variation) study is the appropriate test.
Coefficient of variation is an expression for sample variability relative to
the mean. It is defined as:
C.V. % = SD / Mean x 100%
Where SD is Standard Deviation |
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| Indicator: |
| Salt |
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| Samples: |
10 feed samples about 100g each
The general guideline for evaluating mixer CV’s is: |
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C.V. %
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Rating |
Corrective
Action |
| <10% |
Excellent |
None |
| 10-15% |
Good |
Increase mixing time by 25-30% |
| 15-20% |
Fair |
Increase mixing time by 50%,
look for worn equipment, overfilling, or sequence of ingredient addition |
| >20% |
Poor |
Possible combination of all
the above. Consult extension personal or feed equipment manufacturer. |
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(BASF,KC 9502)
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Particle Size Studies |
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| Feed
manufacturers produce different types of feed in terms of particle size such as
fine, medium and/or coarse to cater the need of different stages or classes of
poultry. |
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| Specifications |
Type of feed |
Bird class |
Stage |
Particle size |
| Fine |
Crumbles/Mash |
Broilers |
Prestarter |
3 mm |
| Medium |
Pellets/Mash |
Broilers |
Starter |
4-5 mm |
| Coarse |
Pellets/Mash |
Broilers |
Finisher |
6-7 mm |
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| Birds
perform their best on diets having uniform particle size. Particle size of
ingredients is important in the overall process of handling and mixing of
ingredients to manufacture formulated feeds (diets) and is critical in
achieving optimal utilization by animals. |
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| Particle size influences: |
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Thus, particle size of feedstuffs and diets becomes an important variable that
influences the efficiency of feed utilized. The distribution of particle size
in a feed must be defined and evaluated in order to maintain a consistent feed
formulation day-after-day. It is useful in studying the effect of processing on
performance of a feed ingredient or diet, and to use as a quality control check
on grinding or rolling. The use of “fine”, “medium”, or “coarse” may not be an
adequate description of particle size distribution in feed ingredients or
diets. These terms are relative and have limited use.
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| Determining and expressing particle size: |
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| The particle
size (diameter), number of particles and surface area per gram of ground feed
are calculated by tabulation of sieving data (using sieve no. 8,10, 14, 28, 48,
100 and 150) and calculation of log normal distribution of particles of a
ground feed. The average particle size on a sieve is calculated as the
geometric mean diameter of the sieves through which the particles passed and
upon which they were retained. The values obtained for geometric mean, particle
size and standard deviation are used to calculate the total surface area of a
sample or total number of particles per gram in a sample. |
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| Samples: |
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| 500g of
ground and mixed sample before processing (pelleting) for each type of feed
manufactured |
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| Guidelines: |
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Soybean Protein Quality |
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Feed
manufacturers normally carry out Urease activity test for Soybean meal to
detect whether it has been properly processed or not to remove the anti
nutritional factors. However, whereas the Urease index is useful to determine
if the soybean meal has been heated enough to reduce the anti – nutritional
factors, it is not very useful in determining if Soybean meal has been
over-processed.
Protein Solubility Index (PSI) is a good index for determining the
over-processing of Soybean meal which is not reflected by the Urease Index. PSI
normally remains high for Soya processed under optimum heat condition and
starts reducing in case of excessive heat treatment. It has been observed that
Soya processed under optimum heat treatment provides the best growth and
performance.
Protein Dispersibility Index (PDI) is more sensitive than Urease index or KOH
solubility for determining the optimum amount of heat processing of Soybean
meal. |
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| Tests |
Acceptable Level |
| Urease activity |
0.05 to 0.2 pH unit change |
| Protein Solubility (0.2%
KOH) |
73% to 85% |
| Protein Dispersibility Index |
15% to 30% |
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| Birds
perform their best on diets having uniform particle size. Particle size of
ingredients is important in the overall process of handling and mixing of
ingredients to manufacture formulated feeds (diets) and is critical in
achieving optimal utilization by animals. |
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| Other studies in soybean meal: |
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Assessment of Calcium Status in Feed |
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Next to energy birds adjust their feed intake based on Calcium requirement. In
other words, birds will eat more feed for want of Calcium. This is called
‘Calcium Hunger’.
Rapid growth potential of broilers, requires enough feed to be consumed and
hence the feed manufacturer has to keep the Calcium level at the marginal
level. Further, in addition to Calcite / Marble powder and DCP, the raw
material used in the feed manufacturing supplies Calcium to the bird.
Feed manufacturers calculate the calcium content for raw materials as per the
NRC standards published. However, this may differ for the raw materials
available in the country. Say for example, in India the estimated calcium
content of maize/corn is more than 0.08% as against the published value of
0.02% as per NRC. This increased content of Calcium in maize/corn significantly
contributes Calcium to the bird. Excess Calcium will bind to Phosphorus (2
molecules of Calcium will bind to one molecule of phosphorus) and make
phosphorus, a costly input for feed manufacturers unavailable to bird.
Further majority of the feed additives used in poultry feed are based on
calcium carbonate carrier, which also contributes significant amount of calcium
to the diet.
Keeping these factors in mind, the assessment of calcium in the raw materials
and final feed is important.
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Pellet Quality Studies |
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These tests indicated below are subjective tests that are not a good measure of
pellet quality
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Measure of fines
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Pellet hardness |
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| Pellet Durability Index
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| Pelleted
feed quality is defined using the pellet durability index (PDI). This is a
simple test in which the pelleted feed is tumbled in a defined period of time
that simulates the transfer and handling of feed (Fairfield, 1994). The ratio
of fines to pellets in the sample after tumbling is the PDI. Thus, feed with a
higher PDI means that the manufactured pellets are more likely to remain intact
prior to feeding. |
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Water Activity of the Feed |
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| The water activity of
feed is a very important aspect of feed, determining its quality during
storage. The growth of the various microorganisms stops at a given level of
water activity and a knowledge of this level is important for feed
manufacturers.
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| Definition: |
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Water activity is
simply the ratio of the water vapour pressure in any kind of feed system
to the water vapour pressure of pure water at the same temperature.
Water activity (aw) = P product / P water
The lowest limit for growth in feed or any other item is around aw 0.6. In the
narrow range between aw 1 and aw 0.6 a large number of microorganisms can grow
which are potentially dangerous to feed and in turn for the birds consuming
this feed. Water activity of feed should be below 0.6 to check the microbial
growth of the feed. |
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Other Studies |
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