Page 161 - Calculating Agriculture Cover 20191124 STUDENT - A

CH 14] Calculating Agriculture 14-11

Feedstuffs contain protein
Animals require protein in their rations which create energy that the animal uses for maintenance,
add weight, and provide a consumable product. Our animal feed researchers analyze feedstuffs for their
protein content and record those findings in feeds tables such as Table 14.1.
In these next set of problems you will be given different feed rations and asked to look up each
feedstuff’s protein percent and calculate the pounds of protein in the feed ration. Finally, you will
calculate the percentage of protein in the ration.
Example: A feed ration contains 100# corn, feed meal, 200 pounds of wheat bran (all analysis) and
200 pounds of cottonseed meal (43%). Calculate the percentage of protein in this ration.
Solution:
a. Look up the digestible protein % for each feed in Table 14.1 and change the protein % to
decimals.
b. Multiply the protein decimals by their respective weights. This will give you the pounds of
protein in each feed,
c. Add up the weights of the feeds.
d. Add up the protein weights.
e. Compare total protein weigh to the total feed weight by division & then multiply by 100% to
convert to a percent,

Digestible
a. feed % protein ——> decimal
100# corn, feed meal 7.0% ——> .070
200# wheat bran, all analysis 13.3% ——> .133
200# cottonseed meal (43%) 35.9% ——> .359

b. feed x decimal = # protein
100 # corn meal x .070 = 7.0#
200 # wheat bran x .133 = 26.6#
200 # cottonseed meal x .359 = 71.8#
c./d. 500 # feed TOTAL protein 105.4# 14

e. 105.4# protein
—————— x 100% = 0.2108 x 100% = 21.08% protein
500.0# feed

Cost based on TDN or Digestible Protein (D.P.)
Another way to measure and compare feedstuff costs is on the basis of TDN or its Digestible Protein
(D.P.) content. The methodology is the same regardless of the consideration; TDN or Digestible Protein.

Example: Which is the least expensive source of T.D.N. (total digestible nutrients), barley (89.4%
T.D.N.) at $9.05/cwt, or corn (83.5% T.D.N.) at $6.64/cwt, and how much cheaper per lb?
_________________ Least expensive source
_________________ price/lb.

Solution: Feed 1 : Feed 2

Barley : Corn

$/units : $/units

$9.05/cwt : $6.64/cwt Perform the division indicated
0.894 0.835

$10.12/cwt : $7.95/cwt
cwt = hundredweight = 100#
$10.12 / 100 # : $7.95 / 100 #

$0.1012 / # : $0.0795 / #

Corn is the least expensive source of TDN
($10.12/cwt - $7.95/cwt =) by $2.17/cwt or $0.0217/lb. Less expensive

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