in
breeding terms it's generally an
animal that is used to
sexually excite another animal. this can be used for either
heat (
estrus) induction,
heat detection or
semen collection.
goats and
sheep especially do not exhibit obvious signs of estrus on their own, and teaser
rams and
bucks are needed to
ferret out who is ...mmmm.... hormonally receptive and who isn't. introducing a male into a
female herd will also sometimes trigger the onset of estrus, which is useful if you want all your females to be bred within a short time of each other.
teaser males are
vasectomized because more often than not, estrus
manipulation is used in conjuction with
artificial insemination. this also allows any old
male to be used as a teaser, without worry that his
undesirable genetics will
screw up the herd.
in semen collection, "sexual preparation" through
teasing is supposed to double the number of
sperm cells in a male's
ejaculate. the male is exposed to the sight or
smell of a
receptive female, then trained to mount either a
live or
dummy mount.
the whole
point of a teaser, in other words, is to stimulate an animal but ultimately deny them any real
sex.
hence, the name.