KEY WORKSHEET: Topic # 3046 Feed Composition and Classification

Topic # 3046
Feed Composition and Classification
1. water, mineral matter or ash, protein, fiber, fat and nitrogen-free extract
2. To measure and identify the amount of energy in a feed.
3. All animals have different nutritional needs. By knowing this need and the nutritional
analysis of the feed it is then possible to feed animals the proper nutrients and in proper
4. Taking the weight of a sample of feed and then drying that sample. wt. of dried sample
= % water 100% - % water = dry matter original wt. of sample
5. Determine the nitrogen content and then multiply by 6.25.
6. Get an original weight of a finely ground sample of feed. Then wash this sample with
ether and get the new weight. Original wt. - new wt.= fat wt. wt. fat = % fat original wt.
7. Get an original weight of a feed sample then boil the sample in a weak acid followed
by a weak alkali to remove the fiber. The new weight subtracted from the original gives
the weight of fiber. wt. fiber = % fiber original wt. The importance of knowing the fiber
content is that feeds high in fiber are not as digestible as feeds low in fiber.
8. Get the weight of a feed sample and then burning the sample to weigh the ashes
{which is the weight of the minerals}. wt. of minerals = % minerals original wt. The
minerals in the grain comes just from what is absorbed through the roots while the leaves
and stems receive from the roots and can also absorb minerals from dust and dirt that
settles on them.
9. 100% - % water - % ash - % protein - % fiber - % fat = NAE
10. Concentrates and roughages
Concentrates are low in fiber and high in digestible nutrients while roughages are high in
fiber and low in digestible nutrients.
11. no
12. a. Walls of animal cells are made mostly of protein while plant cell walls are divided
by cellulose and other carbohydrates.
b. Fat is the form of storage for animals. Plants store their reserves as starches.
c. Plants gain energy from the sun and inorganic materials from the soil and air for the
formation of organic components of the plant.
Animals cannot produce their own organic material so they get their supply from plants
and other animals.
13. The amount of water as a percentage will decrease because the amount of fat
increases to raise the fat percentage. The same is true for protein and minerals compared
to the increase in fat.