In Experiment 1, 164 heifers were assigned to two treatment groups. Each received a CIDR insert for 7 days. Treatment 1 received prostaglandin (PGF2 ), 5 mg; i.m., on day 6 and Treatment 2 received PGF2 on day 7. 86.6% of the heifers (142 of 164) exhibited signs of estrus and were inseminated. 47% of the 142 inseminated were pregnant (33 in Treatment 1 and 34 in 2). In Experiment 2, 71 heifers were assigned to three treatment groups and received a CIDR insert for 7 days and PGF2 on day 7. Treatment 1 received a CIDR and PGF2 . Treatment 2 were injected with ECP, 0.5 mg; i.m., on day 8. Treatment 3 animals were injected with GnRH, 2 mg; i.m., on day 9. All heifers were bred by TAI on Day 10. 50.7 % of the 69 heifers were pregnant (13 in Treatment 1, 10 in 2, and 12 in 3).