Page 159 - Calculating Agriculture Cover 20191124 STUDENT - A

CH 14] Calculating Agriculture 14-9

Example: Using the data from Table 14.1, calculate the percentage Total Digestible Nutrient
(TDN) for a Concentrate: Corn, dent, Grade No. 2 grain. Using the compiled data from
Table 14.1 or as stated in Figure 14.4, this Corn contains 8.7% protein, 2.0% Fiber,
69.2% Nitrogen-Free Extract (NFE), and Ether extract (Fat) of 3.9%. Follow the
solution methodology in Example A and B above.
Solution:
Note: Feedstuff data for Protein, Fat (Ether extract), fiber, NFE (Nitrogen-free extract), and Digestion
Coefficients are derived from Table 14.1. You may refer to Figure 14.4 as that data is derived from
Table 14.1.

Digestion
Total % of nutrient x Coefficient = % digestible nutrient
In feed (Written as a decimal)

Element Digestible Nutrient
(%) (lb)
Note: In feeds when
Protein: 8.7% x 0.77 = 6.7 (protein) 6.7 we consider the
100% to be
Ether extract: 3.9% x 0.90 = 3.5 (fat) 3.5
(fat) equivalent to 100#
then the 6.3%

Fiber: 2.0% x 0.57 = 1.1 (Fiber) 1.1 protein would be
6.3# of protein.
Nitrogen-free 69.2% x 0.93 = 64.4 (NFE) 64.4 Values are rounded
to tenths.
extract (NFE)

To approximate the greater caloric value of fat, the percentage of digestible fat (the Ether
extract) is multiplied by 2.25. In the above example for corn, the TDN would be calculated as:

% %
Digestible protein ........................ 6.7 x 1 = 6.7 14
Digestible fat (Ether extract) ....... 3.5 x 2.25 = 7.9
Digestible fiber ............................ 1.1 x 1 = 1.1
Digestible NFE ............................ 64.4 x 1 = 64.4

80.1% TDN, or
80.1 lb TDN/100 lbs Note:
Note: The 80.1% TDN would be 80.1 pounds for 100# of feed.
Or as kg 100 lbs ≠ 100 kg
(80.1 kg TDN/100kg)

Animal requirements or feeding standards. In the TDN system, the feed requirements (energy)
of farm animals are given as pounds of total digestible nutrients. In addition, the pounds of dry matter
are given to insure that the stated amount of TDN is fed.
Feed Rations. The major nutritional requirements for feeding animals are: energy, protein,
minerals, vitamins, and water. The feedstuffs in rations include grain, hay, silage, and miscellaneous
wastes and by-products that can be combined to meet the daily needs of the animal based on the age,
weight, sex, and use and/or intended use. The greatest need is for energy. Of course, the profit earned
is dependent on the costs of the feed inputs and the exchange of converting the pounds of feed into
weight gain, as with growing animals, or production as with dairy animals, and breeding animals
including bovines (beef, dairy or goats), pigs, sheep, or meat and eggs for poultry.

Measuring Percentages in Feeds and Digestible Protein (DP)

All animals depend upon plants for their food. Digestible Protein (DP) supplied by these
plants differ, hence it becomes important to analyze the content of the feeds from several aspects.

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