In past, producers balanced rations by hand calculation, often
using long tedious trial-and –error methods. But in the
past two decades, industries have adapted computers to every conceivable
task, and the feed industry is no exception. Today, computers
are used to formulate rations utilizing a wide variety of feed.
However, one must realize that this new computerized technology
is a tool, which must be used wisely based on certain principles.
Feed formulation is a process by which different feed ingredients
are combined in a proportion necessary to provide the bird with
proper amount of nutrients needed at a particular age/stage of
production. It requires the knowledge about nutrients, feedstuffs
and nutritional requirement of the birds in the development of
nutritionally adequate rations that will be eaten in sufficient
amounts to provide the level of production at a reasonable cost.
The ration should be palatable and will not cause any serious
digestive disturbance or toxic effects to the birds.
Different classes of birds have different requirements for energy
(carbohydrates and fats), proteins (amino acids), minerals and
vitamins in order to maintain its various functions like growth,
reproduction and egg production. Formulation of rations for poultry
emphasizes the use of linear programming using a computer to derive
the least-cost ration.
Important Considerations in Feed Formulation
Ration (or feed) formulation does not merely involve mathematical
calculations to meet the requirement of the birds, since the result
of the calculation may turn out to be impractical and not ideal
for feeding of poultry. An experienced animal nutritionist, therefore,
needs to evaluate the feed formulation before it can be given
to the birds. Factors to be considered in making good feed formulations
are:
Acceptability to the birds
The ration being formulated has to be palatable enough to stimulate
intake by the birds. Feed refused by the birds is worthless, since
feed has to be consumed and utilized by birds to serve its purpose.
Digestibility
The nutrients in the feed have to be digested and released into
the gastrointestinal tract to be utilized by the birds. Rations
with high fiber content cannot be tolerated by poultry.
Cost
The requirement of the birds can be met through several combinations
of feed ingredients. However, when the cost of these ingredients
are considered, there can only be one least-cost formulation.
The least-cost ration should ensure that requirements of the birds
are met and the desired objectives are achieved.
Presence of anti-nutritional factors and toxins
The presence of anti-nutritional factors in the feed, such as
anti-trypsin factor in soybean meal, affects the digestion of
some nutrients by making them unavailable to the animal. Some
feed ingredients may also contain toxic substances, which may
be detrimental to the animal when given in excessive amounts.
The inclusion of these feed ingredients should therefore be limited
or eliminated from the formulation.
Other factors that should be considered in feed formulation
are texture, moisture and the processing the feed has to undergo.
Merhods of Formulating Rations
There are several methods in formulating rations. All of them
have the same objectives of providing the required balanced nutrients
at the least possible cost.
Trial-and-error Method
This is the most popular method of formulating rations for poultry.
As the name implies, the formulation is manipulated until the
nutrient requirements of the birds are met. This method makes
possible the formulation of a ration that meets all the nutrient
requirements of the birds.
Linear Programming (LP)
This is a method of determining the least-cost combination of
ingredients using a series of mathematical equations. There are
many possible solutions to each series of equations, but when
the factor of cost is applied, there can only be one least cost
combination.
An electronic computer is capable of making thousands of calculations
in a very short time. However, the machine is incapable of correcting
errors resulting from incorrect data and errors in setting up
of the program. Therefore, the resultant rations obtained from
linear programming will be no better than the information and
values which are entered into the programming.
Procedure
Before using the LP approach to ration formulation, the user
should be familiar with the LP program or software package to
be used. Numerous companies market computer software for feed
formulation. The software varies from very simple and straight-forward
to very complex packages intended for large feed manufacturers.
The latter package include applications for formula costing, inventory
control, control of usage of ingredients in limited availability,
production of feed tags, etc. Ration formulation software may
be generalized so that it can be made applicable to all species
of animals or it may be designed with the unique requirements
of specific species such as poultry, dairy cattle, etc. When the
software has been designed for a certain species, it may incorporate
tables of nutrient requirements and tables of typical feedstuffs
and their nutrient values. This can save user time, but it does
not mean that the software will run itself without judgment of
user. No one had yet developed software that will anticipate all
the conditions under which livestock & poultry will fed. Computers
are not able to assess all aspects of ingredient quality, environment
and management. The judgment of the producer and formulator must
be imposed on the computer software. Look for the freedom to make
changes as needed. There is certain information and data entered
into the computer and are generally created in steps as follows:
Available feed ingredients
It is necessary that all the available ingredients are listed
along with the unit cost, as long as the number does not exceed
some practical figure which the machine is capable of handling.
Nutrient composition of feed ingredients
Tables of feed composition using average or typical values may
be used but chemical analysis of a representative sample should
be used if available.
Ration specifications
This generally represents the nutrient requirements and ingredient
limits. In each case, the formulator specifies either a lower
limit and/or an upper limit for each item.
Formulation
After providing all the necessary information, the computer
produces formulas that will meet the desired specifications at
the lowest possible cost. However, the formula should be feasible,
both from a mathematical standpoint and from a nutritional standpoint.
The feedstuff mixture should be acceptable to the birds for which
it is intended.
Suggested nutrient specifications of rations for different
classes of poultry
Nutrient Specifications of Broiler Rations
Description |
Broiler Starter |
Broiler Finisher |
ME (KCal/kg) |
2800 |
2900 |
CP, % |
20.0 |
18.5 |
CF (max), % |
5 |
5 |
Ca, % |
0.9 |
0.9 |
P (available), % |
0.42 |
0.38 |
L.A., % |
0.8 |
0.7 |
Lysine, % |
1 |
0.96 |
Methionine, % |
0.50 |
0.48 |
Meth+Cyst, % |
0.83 |
0.77 |
Nutrient Specifications of Layer Rations
Description |
Chick Starter |
Layer Grower |
Layer Mesh |
ME (KCal/kg) |
2800 |
2800 |
2750 |
CP, % |
17.5 |
16 |
17 |
CF (max), % |
5 |
5 |
5 |
Ca, % |
1 |
1 |
3.6 |
P (available), % |
0.47 |
0.40 |
0.40 |
L.A., % |
0.8 |
1.3 |
0.8 |
Lysine, % |
1 |
0.7 |
0.76 |
Methionine, % |
0.4 |
0.33 |
0.35 |
Meth+Cyst, % |
0.67 |
0.58 |
0.60 |
Nutrient Specifications of Broiler Breeder Rations
Description |
Breeder Starter |
Breeder Grower |
Breeder Layer |
ME (KCal/kg) |
2800 |
2800 |
2800 |
CP, % |
18.5 |
16 |
16 |
CF (max), % |
4.5 |
4 |
4 |
Ca, % |
0.9 |
0.95 |
3.2 |
P (available), % |
0.45 |
0.40 |
0.40 |
L.A., % |
0.7 |
1.0 |
1.2 |
Lysine, % |
1 |
0.76 |
0.78 |
Methionine, % |
0.45 |
0.36 |
0.38 |
Meth+Cyst, % |
0.74 |
0.60 |
0.62 |
Maximum Inclusion Limits of Various Feed Ingredients
Feed Stuff |
Broiler
Starter |
Broiler
Finisher |
Layer
Starter |
Layer
Grower |
Layer
Layer |
Corn |
20 |
25 |
20 |
25 |
30 |
Rice tips |
50 |
50 |
50 |
50 |
50 |
Wheat |
20 |
30 |
20 |
30 |
25 |
Sorghum |
5-7 |
7 |
6 |
10 |
7 |
Rice Polishing |
10 -12 |
10 -15 |
10 |
10 -15 |
10 -15 |
Soybean meal |
20 |
20 |
20 |
10 |
15 |
Canola meal |
5-10 |
5-10 |
5-7 |
5-10 |
10 |
Rape seed meal |
6 |
5 |
7 |
6 |
5 |
Guar meal |
4 |
4 |
4 |
4 |
4 |
Sunflower meal |
2 - 3 |
2 - 3 |
2 - 3 |
5 - 7 |
5 - 7 |
Corn gluten meal 30% |
2 |
2 |
3 |
3 - 5 |
3 |
Corn gluten meal 60 % |
1 |
1 |
2 |
2 |
2 |
Cotton seed meal |
2 |
2 |
3 |
3 |
3 |
Sesame meal |
5 |
5 |
5 |
5 |
5 |
Fish meal |
2 - 5 |
2 - 5 |
2 - 5 |
2 - 5 |
2 - 5 |
Poultry by-product meal |
1 - 2 |
1 - 2 |
1 - 2 |
2 - 3 |
1 - 3 |
Blood meal |
1 - 2 |
1 - 2 |
1 - 2 |
1 - 2 |
1 - 2 |
Tallow |
1 - 2 |
1 - 2 |
1 - 2 |
1 - 2 |
1 - 2 |
Vegetable oil |
1 - 2 |
1 - 2 |
1 - 2 |
1 - 2 |
1 - 2 |
This article has previously been published in THE VETERINARY
NEWS & VIEWS [WEEKLY] and on World Veterinary Association
web site (dated Sep
25, 2003 - 04:03 PM).
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