Page 160 - Calculating Agriculture Cover 20191124 STUDENT - A

14-10 Feeds and Feeding CH 14]

Most feeds are analyzed in terms of the following constituents:
1. crude protein
2. fats and oils−sometimes called "other extracts"
3. crude fiber
4. nitrogen-free extract−mainly carbohydrates; i.e. starches & sugars
5. water
6. ash−the residue when the feed is burned
Let us consider a mixture of feeds. In balanced rations, the ration is such that it meets the daily
nutritive requirements of the animal based on its age, weight, sex and use. In rations for different
animals, the digestible protein (D.P.) content and animal requirement for DP usually varies
somewhat as follows:

Beef Cattle 10% to 20% DP Horses 10% to 15% DP
Dairy cattle 12% to 25% DP Poultry 11% to 25% DP
Hogs 12% to 20% DP Sheep 10% to 17% DP
Feed Stuff Percentages. Feeding experiments are being carried on continually, and
various standards are being recommended for different animals at different ages, depending
upon the purpose of the feeding.

Example: From the following mix of feeds in a ration for dairy cows, what is its percent digestible
protein, and is it within the recommended range for dairy cows?

Cottonseed meal 20 lb. Molasses 12 lb.
Corn meal 33 lb. Alfalfa meal 5 lb.
Wheat bran 15 lb. Ground limestone 2 lb.
Ground whole oats 12 lb. Salt 1 lb.
Solution:
Values are found in Table 14.1.

% DP Decimal Digestible
DP DP Protein
20 lb. cottonseed meal (35.9) 0.359 x 20 lb. = 7.18 lb.
35 lb. corn meal (6.5) 0.065 x 35 lb. = 2.28 lb.
15 lb. wheat bran (13.3) 0.133 x 15 lb. = 2.00 lb.
12 lb. ground whole oats (9.0) 0.090 x 12 lb. = 1.08 lb.
12 lb. molasses (4.7) 0.047 x 12 lb. = 0.56 lb.
5 lb. ground limestone —— —
1 lb. salt —— —
100 lb. TOTAL TOTAL 13.10 lb.

DP# 13.10#
Digestible Protein % = —–——— x 100% = ——— x 100% = 13.10% DP
Total Weight 100#

Hence the digestible protein is 13.1% of the ration. Since the range of digestible protein
content for dairy cows is from 12% to 25% and the percent digestible protein of this feed
mixture is 13.1%, it is within the recommended range.

Example Given the following feedstuffs in a ration, 100# wheat, 250# cracked corn,
and 100# of oats, what percentage of the ration is 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
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