South Bend news-times. (South Bend, Ind.) 1913-1938, 1918-05-25
INFORMATION FOll FARMERS
AND ORCHAkDISTS
AGRICULTURE
Protein and It's Relative
Value In Animal Nutrition

BY VI. A. Nye. Asst County Agent.
Protein Is known BY the fact that
" contains nitrogen. Il serves the
purpose Of building up tissue in the
body. such az muscle. skin. etc, and
constitutes the curd Of milk Lean
meat and the white OF an egg are
examples Of nearly pure protein.
All feeds contain more or less pro-
tein Among hays. clover. alfalfa.
cowpea. or SOY bean hay contain the
largest amount. Among the COM
mon concentrates linseedmeal. cot
tonseed meal and wheat bran con-
tain relatively large quantities A
certain amount OF protein is indis-
pensible in a ration as nothing else
can be substituted for it by the ami
NAL
Because Of their great variety and
compiexity. the heterogeneous com
pounds are the most difficult OF all
plant substances for study and class
ifcation. For years able organic
chemists have been attacking the in
tricate problems Of their structure
and composition with great energy
and patience. Although their work
has greatly advanced our knowledge,
yet little more than a beginning has
been made in setting forth the diff
ferences in the composition OF the
various heterogeneous or protein COM
pounds and in pointing out their
relative values as nutrients for ami
mails In discussions of feeding
stuffs and the nutrition of animals,
the terms crude protein, protein.
and amids are commonly used for
designating the various classes of
heterogeneous.
Crude protein is the term employ
ed 10 designate all the heterogeneous
compounds of the plant and en-
braces two great groups Of nitro
eenous plant compounds. proteins
and amids.
The amids may be termed the
building stones OF the proteids for
from them the plant constructs the
more highly organized proteins. and
on decomposition the proteins are
again broken down into these more
simple bodies. These compounds
are the porta Die building compounds
OF the plant. for they are soluble in
its juices and hence may be convey
ed whenever needed throughout the
plant structure.
PrOteins are the. more highly or
ganized forms of crude protein. They
in many cases not transportable in
the juices of the plant. The amids
may be compared to the bricks OF a
house and the proteins 10 the COM
pleted structure
Only when the food proteins yield
in digestion a mixture or amino
acids in the proper proportions for
the construction OF the body pro-
teins without having a lot of certain
Of them left over, because OF run
ming short of some of them which
are necessary for the required pat
tern, can the animal use the pro-
teins Of the diet with a high degree
Of efficiency. He cannot change the
pattern 10 suit the food supply.
neither can he transform one amino
acid into another, at least this is
true of most of them.
There are, therefore. good pro-
teins and poor proteins. While GER
tain of the proteins Of both the
wheat and the corn kernel are en-
tirely inadequate when fed as the
sole protein of the diet. because of
their entire lack OF certain amino
acids, there are in the protein mix
ture. which is contained in each OF
these grains. a number OF different
prOteins with different yields of
these digestion products. and the
dihciencies of one are in part made
good by the yield of the others. so
that there are present in the kernel
of wheat or corn all the amino acids
necessary for the construction OF the
body proteins. With experiments
conducted for eight years with
young pigs, DR. +. V. McCullum of
John Hopkins university. has shown
how much of the proteins OF the in
| dividual naturally occurring food