How to prepare feed for poultry? Pearson Square Method to formulate the feed. Example

1. Feed Formulation
Feed formulation is the process of quantifying the amounts of feed ingredients
that need to be combined to form a single uniform mixture (diet) for poultry that
supplies all of their nutrient requirements.
Since feed accounts for 65-75% of total live production costs for most types of poultry
throughout the world, a simple mistake in diet formulation can be extremely
expensive for a poultry producer.
Feed formulation requires thorough understanding of the:
a) nutrient requirements of the class of poultry (e.g., egg layers, meat chickens or
breeders);
b) feed ingredients in terms of nutrient composition and constraints in terms of
nutrition and processing, and
c) cost and availability of the ingredients.
Except for a few feed manufacturers who keep to the standards in poultry feed
formulations, many feed companies in the country make very poor quality feeds, a
situation which has led huge losses.
Poor quality feeds lead to a:
a) slow growth in chickens,
b) low egg production,
c) diseases or even death.
Making poultry feeds on the farm is one of the best ways to maintain quality and cut
the cost of production. Material is available cheaply, especially after the harvesting
season. Depending on the cost of raw material, farmers who make their own feeds at
home save between 30 to 50 per cent for every 70kg bag of chicken feed, depending
on the source of their raw materials.
Due to government regulation, major feed companies have reduced the standard
quantity of feed from 70kg to 50kg per bag, but the price of feed still remains almost
the same.
This means that farmers who are able to make their own feeds make great savings on
feeds which take up to 80 per cent of the production costs.
Toformulate feeds, farmers have to use the Pearson Square Method. In this
method, the digestible crude protein (DCP) is the basic nutritional requirement for
any feed preparation for all animals and birds.

2. Pearson Square Method
The Pearson Square Method of balancing rations is a simple procedure that has
been used for many years. It is of greatest value when only two ingredients are to be
mixed. In taking a close look at the square, several numbers are in and around the
square. Probably one of the more important numbers is the number that appears in
the middle of the square. This number represents the nutritional requirement of an
animal for a specific nutrient. It may be crude protein or TDN, amino acids, minerals
or vitamins.
In order to make the square work consistently, there are three very important
considerations:
1. The value in the middle of the square must be intermediate between the two
values that are used on the left side of the square. For example, the 14 percent
crude protein requirement has to be intermediate between the soybean meal
that has 45 percent crude protein or the corn that has 10 percent crude
protein. If barley is used that has 12 percent crude protein and corn that has
10 percent crude protein, the square calculation method will not work because
the 14 percent is outside the range of the values on the left side of the square.
2. Disregard any negative numbers that are generated on the right side of the
square. Be concerned only with the numerical differences between the
nutrient requirement and the ingredient nutrient values.
3. Subtract the nutrient value from the nutritional requirement on the diagonal
and arrive at a numerical value entitled parts. By summing those parts and
dividing by the total, you can determine the percent of the ration that each
ingredient should represent in order to provide a specific nutrient level.
Always subtract on the diagonal within the square in order to determine parts.
Always double check calculations to make sure that you did not have a
mathematical error. It also is very important to work on a uniform basis. Use a
100-percent dry-matter basis for nutrient composition of ingredients and
requirements and then convert to an as-fed basis after the formulation is
calculated.

3. Corn represents (31.0 / 35.00) x 100 of the ration, or 88.57 percent. Soybean meal
represents (4.0 / 35.00) x 100 of the ration, or 11.43 percent. Check of the
calculation:
88.57 lb corn x 10.0% CP = 8.86
11.43 lb SBM x 45.0% CP = 5.14
100.00 lb mixture contains = 14.00 lb CP, or 14 percent.
Example
Formulate 450 lbs of a 28% CP ration using Cottonseed Meal (49% CP) and Millet (3%
CP).
CSM 49% CP 25 parts CSM
Millet 3% CP 21 parts Millet
46 Total Parts
 How many pounds of cottonseed meal will be used?
(25 parts cottonseed meal / 46 total parts) x 100= 0.54 parts
cottonseed meal
0.54 parts cottonseed meal x 450 lb ration = 243 lbs cottonseed
meal needed
 How many pounds of millet will be used?
(21 parts millet / 46 total parts) x 100 = 0.46 parts millet
0.46 parts millet x 450 lb ration = 207 lbs millet needed
 Double check your answer:
243 lbs cottonseed meal + 207 lbs millet needed = 450 lbs ration
28%