Page 162 - Calculating Agriculture Cover 20191124 STUDENT - A

14-12 Feeds and Feeding CH 14]

Least Cost Decisions for Feed
Being able to calculate the least cost a feed needs to be is a calculation for negotiating the price of
competing feeds and to provide the same nutrient value in feeding. When using this calculation
algorithm the feeder is determining what feed prices need to be for equality in cost.

Example: If soybean oil meal (37%) is selling for $673/ton, how much can you afford to pay per
cwt. for linseed meal (27%) to obtain equal D.P. value?

_____________________ price
Solution algorithm:
This is best solved as a ratio and proportion. However, the units must first all be made equal.
That is, convert tons to hundred weight (cwt.). There are 20cwt in each ton.

$673 / ton = $673 / 20 cwt. = $33.65/cwt

Soybean : Linseed

Price Feed 1 Price Feed 2
Units = Units

$33.65 $ L
——— = —— get $ L by itself
0.37 0.27

(0.27) $33.65 $ L (0.27) multiply by
——— x ——— = —— x ——— the reciprocal
1 0.37 0.27 1

(0.27) x $33.65
—————— = $ L
0.37

$ 24.555 = $ L Price/cwt of the linseed meal equal to soybean oil meal

What is calculated is the maximum price to pay for linseed meal. When the price exceeds this value
then soybean oil meal is the less expensive purchase for feeding.

Simple Rations for animals and calculating DP and TDN

Animal rations. The following examples of balanced rations for different classes of stock are
represented as guides in selecting efficient balanced rations adapted to various conditions. These
examples should not limit choices for particular feed combinations. Unless otherwise indicated, the
amounts of feed shown in the tables are the amounts to be fed per head daily. For animals of different
sizes than stated in the tables, the amounts of feed should be increased or decreased in accordance with
the amounts of nutrients recommended.
Other grains may be substituted for the grains in these example rations. If the grain substitutes is
higher or lower in protein than the grain which it replaces, the amount of protein supplement in the
ration should be changed to provide approximately the same percentage of protein in the ration.
Instead of the protein supplements used in the various example rations, other supplements can be
substituted, such as brewers’ dried gains, distillers dried grains, corn gluten meal, and peanut oil meal.
If the percentage of protein differs appreciably from that in the supplement used in these examples, the
amount should be changed accordingly. In making any substitution of protein supplements in a ration
for swine or poultry, one must be sure that the ration will furnish the protein which is of proper quality.
The proportions of protein supplements in the example rations are based on the most common
grades of the various supplements. For example, the computations have been based on cottonseed meal
of 41 percent protein grade; linseed meal, expeller or hydraulic process, 34 percent protein guarantee;
and soybean oil meal, solvent process, 44 percent protein guarantee (this data and percents are defined
in Table 14.1 for each feedstuff). If the protein supplement used has a decidedly higher or lower
protein content than stated, the amount of supplement needed will be altered correspondingly.

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