Although treatment with PGF2a did not affect the
concentration of T and E2, invariably it was associated
with a successful mount and ejaculation, which usually
was the first attempt, although occasional false mounts
were observed, with success achieved at the second
mount. Despite a wealth of data to support the linkage of
exogenous PGF2a and boar libido, the mechanism
involved remains undetermined. That PGF2a has been
associated with maintenance of circulating steroid
concentrations in boars receiving GnRH implants, and
that estrogen or testosterone replacement therapy can
restore and maintain libido in castrates, an effect
involving the production of gonadal steroids might be
anticipated. However, based on the present data,
improved libido was achieved without an effect on
gonadal steroid production in castrated boars.