things to be observed are where and how
much, when, and on what your cattle will graze: thus it suits goats
better to graze on rough and mountain land than in fat pastures,
while the contrary is true of horses. Nor are the same places fit for
grazing for all kinds of cattle both in summer and winter: thus flocks
of sheep are driven from Apulia a long distance into Samnium to spend
the summer, and are reported to the tax farmer to be registered lest
they violate the regulations of the censor.[112]

"In the same way mules are driven in the summer from the prairie of
Rosea to the high mountains of Gurgures.

"The rules for feeding each kind of live stock in the barn yard must
also be studied, as, for instance, that hay is fed to the horse and
the ox, while it will not do for swine which require mast, and that
barley and beans should at intervals be fed to some kinds of stock,
lupines to draft cattle and alfalfa and clover to milch cows.
Furthermore, it is desirable to feed the ram and the bull more heavily
for thirty days before admitting them to the flock and the herd, the
purpose being to increase their strength, while on the other hand the
feed of the cows is cut down at that time because it is deemed that
they breed most successfully when they are thin.

"The next consideration is concerning breeding, which I call the period
between conception and birth, for these are the beginning and the end
of pregnancy. First of all then we should consider the stinting and
the season at which this should be accomplished, for as the
season from the rising of the west wind to the vernal equinox
(February-March) is considered best for swine, so that from the
setting of Arcturus to the setting of Aquila (May-July) is best for
sheep. Furthermore, a rule should be made that the male animals are
kept apart from the females for some time before they are bred, a
period which neatherds and shepherds usually fix at two months. The
next consideration is of the rules to be observed while the animal
is pregnant, because the periods of gestation differ in the several
domestic animals: thus the mare goes twelve months, the cow ten, the
ewe and the goat five and the sow four.

"In Spain is reported a phenomenon of breeding which seems incredible,
but is nevertheless true, namely: that on Mount Tagnus on that part of
the coast of Lusitania near the town of Olisippo, mares are some
times impregnated by the wind,[113] some thing which often happen