Oestrous synchronization in cattle using progesterone and a PGF analogue

A regime consisting of in jections of 150mg and 100mg of progesterone subcutaneously (s.c.) 3 days apart, followed 2 days later by a single injection intramuscularly (i.m.) of a PGF analogue (ICI 80996), and after further 12 hr interval, 1000 i.u. PMSG s.c. was used to synchronize oestrous periods in 16 cows. Eight cows (50%) conceived after insemination with frozen semen after synchronized oestrus; 14 cows came into oestrus over a 36-hr period.