Several hormonal treatments have been established to
synchronise oestrus in order to facilitate and reduce time
consumed on oestrus detection. Since the 1970s, when
preparations of prostaglandin F2α were introduced into
veterinary medicine [2-6], developing oestrus synchronisation
programs has aroused great interest. During the
first two decades, the AI after synchronisation programs
was based, however, on oestrus detection, or alternatively,
double inseminations on consecutive days [7-9]. In Finland,
where the number of beef cattle is small, the semen
used for breeding purposes has to be imported from
abroad, and thus, it is fairly expensive. Owing to this, the