milk, and the dams yield it. Each
generation in its turn becomes more completely and fully adapted to
the circumstances amid which they are reared, and if bred
indiscriminately with any thing and every thing else, we by and by
have the common mixed cattle of New England, miscalled natives; or if
kept more distinct, we have something approaching the Devon, the
Ayrshire, or the Jersey breeds.

A due consideration of the natural effect of climate and food is a
point worthy the special attention of the stock-husbandman. If the
breeds employed be well adapted to the situation, and the capacity of
the soil is such as to feed them fully, profit may be safely
calculated upon. Animals are to be looked upon as machines for
converting herbage into money. Now it costs a certain amount to keep
up the motive power of any machine, and also to make good the wear and
tear incident to its working; and in the case of animals it is only so
much as is digested and assimilated, _in addition to the amount thus
required_, which is converted into meat, milk or wool; so that the
greater the proportion which the latter bears to the former, the
greater will be the _profit_ to be realized from keeping them.

There has been in New England generally a tendency to choose animals
of large size, as large as can be had from any where, and if they
possess symmetry and all other good qualities commensurate with the
size, and if plenty of nutritious food can be supplied, there is an
advantage gained by keeping such, for it costs less, other things
being equal, to shelter and care for one animal than for two. But our
pastures and meadows are not the richest to be found any where, and if
we select such as require, in order to give the profit which they are
capable of yielding, more or richer food than our farms can supply, or
than we have the means to purchase, we must necessarily fail to reap
as much profit as we might by the selection of such as could be easily
fed upon home resources to the point of highest profit.

Whether the selection be of such as are either larger or smaller than
suit our situation, they will, and equally in both cases, vary by
degrees towards the fitting size or type for the locality in which
they are kept, but there is this noteworthy difference, that if larger
ones be brought in, they will not only diminish, but deteriorate,
while if smaller be brought in, they will enlarge _and improve_.

The bestowal of food sufficient both