Pearson square method

PEARSON SQUARE METHOD

I. Pearson square method

  • Draw a pearson’s square for determining the proportions (or) ratio of feeds to be mixed.
  • Partition the feeds as high protein and low protein feeds.
  • Place the percentage of crude / digestible crude protein desired in the center of the pearson’s square.
  • Place the average percentage of crude / digestible crude protein present in high protein feeds on the left side upper corner of this square.
  • Place the average percentage of crude / digestible crude protein present in low protein feeds on the left side lower corner of this square.
  • Take about the diagonal lines in the square.
  • Draw the difference between the figures on the left hand sides and the center figure and place these on the right hand corners of the square, in the direction of diagonal lines.
  • The figures obtained on the right hand side corners are the parts or proportions in which ratio the given feeds should be mixed to obtain the mixture of desired CP/DCP percentage.
  • Pass the feeds to be mixed through grinder and then mix the ground feeds in horizontal / vertical mixer.
  • Fill the gunny bags using the shovel (or) directly fill it from the mixer.
  • Label the feed mixture along with the weight neatly, clearly and legibly.

Note

  • Prepare 100 kg concentrate mixture containing 18 % DCP using maize grain, wheat bran and linseed cake consisting of 10, 12 and 30 % DCP, respectively.

Solution

Average DCP of low protein feeds = Maize + Wheat bran / 2

                                                         = 10 +12 / 2 = 11%.

DCP content of high protein feed (linseed cake) = 30%

image

ie.

100 kg should contain ? parts of linseed cake

                    = 100 x 7 / 19 = 36.84 kg (or) 37 kg49

Therefore,

  • Amount of low protein feeds = 100 – 37 = 63 kg.
  • This should be distributed among the low protein feeds equally.
  • Hence, amount of maize = 63 / 2 = 31.5 parts.
  • Therefore, amount of wheat bran required = 31.5 parts.

Verification

Feedstuff
Parts
% DCP supplied
Linseed cake
37.0
37 x 30 /100 = 11.1
Maize
31.5
31.5 x 10 /100 = 3.15
Wheat bran
31.5
31.5 x 12 / 100 = 3.78
Total
100
18.03 %
  • 19 kg of mixture will contain 7 parts of linseed cake

Example

  • Minerals consisting of bone meal and common salt may also be added in required quantity before grinding and mixing.
Last modified: Wednesday, 18 April 2012, 6:16 AM