The following are the ages at which various animals become
capacitated for sexual commerce. The ewe and the she-goat are sexually
mature when one year old, and this statement is made more
confidently in respect to the she-goat than to the ewe; the ram and
the he-goat are sexually mature at the same age. The progeny of very
young individuals among these animals differs from that of other
males: for the males improve in the course of the second year, when
they become fully mature. The boar and the sow are capable of
intercourse when eight months old, and the female brings forth when
one year old, the difference corresponding to her period of gestation.
The boar is capable of generation when eight months old, but, with a
sire under a year in age, the litter is apt to be a poor one. The
ages, however, are not invariable; now and then the boar and the sow
are capable of intercourse when four months old, and are capable of
producing a litter which can be reared when six months old; but at
times the boar begins to be capable of intercourse when ten months. He
continues sexually mature until he is three years old. The dog and the
bitch are, as a rule, sexually capable and sexually receptive when a
year old, and sometimes when eight months old; but the priority in
date is more common with the dog than with the bitch. The period of
gestation with the bitch is sixty days, or sixty-one, or sixty-two, or
sixty-three at the utmost; the period is never under sixty days, or,
if it is, the litter comes to no good. The bitch, after delivering a
litter, submits to the male in six months, but not before. The horse
and the mare are, at the earliest, sexually capable and sexually
mature when two years old; the issue, however, of parents of this
age is small and poor.