Two experiments were carried out to determine the effect of Kisspeptin-10 on plasma LH concentrations and follicular dynamics during the luteal phase in cattle. We tested the hypothesis that a single treatment of Kisspeptin-10 will increase plasma LH concentration and the diameter of the dominant follicle， and induce ovulation during the luteal phase of the estrous cycle in cattle. In the Experiment 1， Hereford-cross heifers (n = 28， 14-16 mo) were given PGF2α im to induce luteolysis and ovulation. On Day 5 (Day 0 = ovulation)， a new follicular wave was induced by ultrasound-guided follicular ablation. Heifers were treated on Day 10 (4 days after wave emergence) with 100 μg GnRH im (n = 9)， 2 mL saline im (n = 7)， 1 mg Kisspeptin-10 im (Kp im， n = 6) or 1 mg Kisspeptin-10 iv (Kp iv; n = 6). Blood samples were collected at -60， -15， 0， 5， 15min (0 min = time of injection) and every 15 min thereafter until 3 h. Transrectal ovarian ultrasonography was performed at 12 h intervals from Day 10-14. In Experiment 2， non-lactating beef cows on Day 5 were treated with 100 μg GnRH im (n = 9)， saline im (n = 5)， 10 mg of Kisspeptin-10 iv (Kp 10 mg; n = 5) or 15 mg of Kisspeptin-10 iv (Kp 15 mg; n = 5). Blood samples were collected at -15， 0， 15， 30， 60， 120， 180 min and twice daily ovarian ultrasonography was done from Day 5-10. In Expt 1， plasma LH concentrations increased for 1 h following Kp iv administration. The peak concentration occurred at 15 min and was higher in the Kp iv group than in the Kp im group (P = 0.01). The LH peak was 3.5-folds higher in the GnRH group than the Kp iv group (P < 0.0001). In Expt 2， GnRH induced higher (P < 0.001) plasma LH concentrations for all time-points than other groups. Kp 15 mg at peak (15min)， 30 and 60 min induced higher (P < 0.0001) plasma LH concentrations than Kp 10 mg and saline. Kisspeptin-treated animals did not ovulate in either experiment while GnRH induced ovulation (n = 5/9 in Expt 1; 9/9 in Expt 2). The diameter of the dominant follicle was greater (P = 0.02) at 12-48 h after kisspeptin treatment (Kp groups combined) than the Saline group in Expt 2. In conclusion， Kisspeptin-10 increased plasma LH concentrations and follicle size， and although plasma LH concentrations were higher after iv than im administration， but at the doses used， Kisspeptin-10 did not induce ovulation during the luteal phase in cattle.