866 ALFALFA FARMING IN AMERICA. 
less like it chemically. ‘The toughness and firmness of forage 
plants depend largely on this constituent. Cotton and linen are 
nearly pure cellulose. Obviously the crude fiber is of inferior 
nutritive value; indeed, there is good reason to believe that in 
many cases such of it as is digested by animals is utilized at an 
expenditure of more’ energy than is yielded by the digested fiber. 
The nitrogen-free extract includes starch and the sugars as 
well as other less well known carbohydrates. In some tables 
this srcup is listed as carbohydrates, without due regard, how- 
ever, for the fact that the cellulose of the crude fiber is a car- 
pohydrate. 
The crude fat extracted from hay, or from other materials, 
obtained by drying the green parts of plants, includes some 
chlorophyl, the green substances of leaves, and other compounds 
that are not fats, as well as any fat in the feed. 
The water of a feed possesses no nutritive power and is not 
different from water taken by drinking. 
Studying now the table showing the percentages of the sev- 
eral constituents of the water-free hay, it will be seen that there 
are progressive changes as the plant becomes more mature. It 
must not be supposed, however, that there is an actual decrease 
in the total amount of any food principle in the crop, but only 
that as maturity takes place certain constituents are produced 
in greater proportion, thus adding to their percentage amount 
while correspondingly reducing the percentage of the constitu- 
ents produced at a slower rate. 
The hay produced by cutting when the alfalfa was about ten 
per cent. in bloom is seen to be richer in ash, protein and fat 
than that produced by later cuttings, while the crude fiber and 
the nitrogen-free extract increase in percentage as the plant 
matures. The especially valuable protein is present to an extent 
more than one-fourth greater in the hay made at the first stage 
than it is in that made at the third stage, while the questionable 
crude fiber is more abundant in the later stages. 
Digestibility of Alfalfa—wWhile it is true that a certain residue 
of indigestible matter is necessary for animals, and especially 
for ruminants, which are accustomed to bulky feed, we seldom 
need to give attention to this in practice, as feeds are ordinarily 
excessively supplied with such indigestible substances. Quite 
the reverse, we are justified in prizing more highly those feeds 
which show a high degree of digestibility. A proper apprecia- 
tion of alfalfa hay thus requires consideration of its digestibility. 
The digestibility of the hays referred to was ascertained and 
the following table shows the results. It gives the percentages 
