meant the amount of fat it
is capable of producing, and which is obtained by dividing its quantity
by 2.5. Applying this principle to the analyses of the milk, it appears
that the relative proportions of the two great classes of nutritive
substances stand thus:--

Flesh Respiratory, expressed in
forming their fat equivalent

Cow 3.4 6.0
Ewe 4.5 6.2
Goat 4.0 5.4

Taking the general average, it may be stated, that for every pound of
flesh-forming elements contained in the food of the sucking animal, it
consumes respiratory compounds capable of producing one and a half
pounds of fat, and this does not differ materially from the ratio
subsisting between these substances in the lean animal. When the young
animal is weaned, it obtains a food in which the ratio of nitrogenous to
respiratory elements is maintained nearly unchanged; but the latter, in
place of containing a large amount of fatty matters, is in many cases
nearly devoid of these substances, and consists almost exclusively of
starch and sugar, mixed most commonly with a considerable quantity of
woody fibre.

A very large number of analyses of different kinds of cattle food have
been made by chemists, but our information regarding them is still in
some respects imperfect. The quantity of nitrogenous compounds and of
oil has been accurately ascertained in almost all, but the amount of
starch, sugar, and woody fibre is still imperfectly determined in many
substances. This is due partly to the fact that the nitrogenous and
fatty matters were formerly believed to be of the highest importance,
and might be used as the measure of the nutritive value of food to the
exclusion of its other constituents, and partly also to the imperfect
nature of the processes in use for obtaining the amounts of woody fibre,
starch, and sugar. These difficulties have now, to a certain extent,
been overcome, and the quantity of fibre and of respiratory elements has
been ascertained, and is introduced, so far as is known, in the
subjoined table:--

TABLE giving the Composition of the Principal Varieties of Cattle Food.

_Note._--Where a blank occurs in the oil column, the quantity of that
substance is so small as to be unimportant. When the respiratory
elements and fibre have not been separated, the sum of the two is given.

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