Page 154 - Calculating Agriculture Cover 20191124 STUDENT - A

14-4 Feeds and Feeding CH 14]

PERCENTAGE OF FEEDS IN A RATION
Often it is important to know the percentages of the feedstuffs selected for inclusion in a
ration.

Example: Given a ration composed of 100# wheat, 250 pounds of cracked corn, 100# of
oats. What percent of this ration is made of wheat?

Solution:

a. Add together the units of each feedstuff.

100 # wheat
250 # cracked corn
100 # oats
450 # total weight

b. Compare wheat to the total.

100# wheat
————— x 100% = 0.2222 x 100% = 22.22% wheat
450# total

Pearson Square
With the increased complexity of feed rations for animals and the larger enterprises for
feeding cattle, dairy, and poultry, utilizing commercially mixed feeds are more common. The
feeder choosing to mix feed in some manner should be absolutely sure that they prepare a
nutritionally balanced diet for their animals considering the protein, digestible nutrients,
and energy requirements for the animals being fed.
The larger commercial feed companies and feeders who do their own mixing or
formulating, generally rely on the services of a nutritionist and computer programs or
spreadsheets in formulating their rations. Even though they are more time-consuming, and
fewer factors can be considered simultaneously, a good job can be done in formulating
rations by either the (1) trail and error method or (2) the Pearson square method.
The Pearson square follows an algorithm used in milk processing plants where it is
desired to determine the proportions of each, milk and cream, to mix. The fat percentages of
each are known, and the amounts of each, milk and cream, can then be determined when
making either milk or cream products.
The following example will demonstrate how to use the Pearson square method in
formulating a poultry ration based on the amount of protein.

Example: A poultryman has on hand 200 pounds of corn containing about 9% protein. He
can purchase a 36 percent protein supplement, which is reinforced with
minerals and vitamins. A ration containing 16% protein is desired. How much of
each, corn and protein supplement, is to be mixed to reach the desired 16%
protein content level.

Solution algorithm:

1. Draw a square, and place the number 16 for 16% Protein in the center of it. At the top
left and right corners write these labels: %, and Parts.

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