If'

^1

V,, CHAPTER IX

'//!»
J FEEDS

I The raw materials of feeds vary greatly in their composition,

j$j| their feeding and commercial values depending upon their con-

.)' ;j tent of protein, fat, mineral matter, carbohydrates and vitamins

and upon the ease with which food elements are digested and

;j'r assimilated. There is much difference in the feeding value

,f' of protein and fat, according to the sources from which they are

f derived. The degree of utilization of these products can not

!M' always be measured with exactness by chemical means but it

*ft!j must be determined from feeding trials with animals. However,

4: chemical analysis furnishes the best available means for estimat-

Jr! ing approximate feeding values from percentage composition.

J This is especially true of commercial ready-mixed feeds, which

[^ are often made up from many different plant and animal sources;

' 1 • chemical analysis furnishes the only quick method for determin-

4|1 ing their approximate commercial value.

; I ! Composition of Some Common Feeds.—If the feed is made

(I j from the whole grain the composition of the groups will be about

'I j as represented in the table below and if made up of grain by-

'4; | products, with the more valuable parts taken out and substituted

j| j with cheaper materials, it is often possible to detect the deception

•!$j j by analysis.

The analysis of feeds commonly includes the determination
of moisture, ash, crude fat, crude fiber, crude proteins, carbo-
hydrates and pentosans. The entire carbohydrate group is often
expressed as " nitrogen-free extract/' which is obtained by
deducting the sum of all other groups from 100.

Most states now have laws which control the manufacture and
;l'« ' sale of feeds. These laws usually require a guarantee of the

J1 |}f j per cent of ether extract, crude protein, fiber and ash. The average

•' 'iff ! composition of the principal cereal grains is tabulated as follows

' '# by Villier and Coffin.

142

l*i=

bl

(•I
, M i
|V|f)j|
11|
'