Thereafter the CIDRs were removed and 2 injections of PGF [50 mg
dinoprost tromethamine, i.m.] were given on Day -3 before breeding. Females observed in estrus
within the first 60 h received AI approximately 12 h later and all remaining females (not
observed in estrus) received timed AI with an injection of GnRH [100 μg; i.m.] at 72 h after PGF
by one of two AI technicians using semen packaged as described above from one of four Angus
bulls.