Our objective was to evaluate treatments to increase fertility of timed-AI (TAI) services of lactating dairy cows without a corpus luteum (CL) at the time of the PGF injection of Resynch initiated 32 ± 3 d after AI (RD32; GnRH-7d-PGF-56h-GnRH-16h-TAI). In Exp1, blood collection and ovarian ultrasound was conducted (n = 555) at the PGF of RD32 to define a cutoff value for CL size that allows creating groups of cows with low and high fertility after TAI. P/AI were analyzed by logistical regression using PROC GLIMMIX of SAS. Based on P/AI, the CL size selected was 15 mm [CL ≥ 15 mm = 33.2%; (165/497) vs. NoCL or CL < 15 mm = 10.3% (6/58); P < 0.01]. In Exp2, cows without a CL or a CL < 15 mm (NoCL) were randomly assigned to (1) Ovsynch plus progesterone (P4) [OvP4; GnRH (G1) and CIDR-7d-PGF and CIDR removal-56h-GnRH-16h-TAI; n = 212] or (2) presynchronization with GnRH (PreG) 7 d before Ovsynch [PreGOv; GnRH-7d-GnRH(G1)-7d-PGF(P)-56h-GnRH-16h-TAI; n = 192]. Cows with a CL > 15mm (CLPG) at PGF of RD32 (n = 1,797) completed RD32 to receive TAI. Binary data were analyzed by logistical regression using PROC GLIMMIX whereas quantitative data were analyzed by ANOVA using PROC MIXED of SAS. At 39 d after AI, overall P/AI were similar (P = 0.13) for cows in OvP4 (34.4%), PreGOv (35.9%), and CLPG (31.1%). Cows inseminated in estrus had similar (P = 0.32) P/AI [41.4% (n = 29) OvP4, 24.4% (n = 41) PreGOv, and 34.1% (n = 173) CLPG] but P/AI tended (P = 0.06) to differ for TAI cows (33.3% OvP4, 39.1% PreGOv, and 30.8% CLPG). Pregnancy losses were similar (P = 0.29) for cows in OvP4 (2.9%), PreGOv (8.7%), and CLPG (11.6%). Ovulatory response to PreG was 86.0%. At G1, cows with a CL (86.6 vs. 16.4%; P < 0.01), cows with P4 > 1ng/mL (82.8 vs. 31.8%; P < 0.01), P4 concentrations (3.7 vs. 1.1 ng/mL; P < 0.01), and cows with a follicle > 10 mm (94.9 vs. 80.9%; P < 0.01) was greater in PreGOv than OvP4 group. Ovulatory response to G1 was 71.9 vs 58.3% for OvP4 and PreGOv (P = 0.03). At the PGF before TAI, more cows had a CL in PreGOv than OvP4 (92.1 vs. 77%; P < 0.01), cows with P4 > 1 ng/mL was similar (79.1 vs. 82.7%; P = 0.50), but P4 concentrations were greater in PreGOv than in OvP4 (4.1 vs. 2.6 ng/mL;P < 0.01). We conclude that presynchronization with GnRH 7 d before Ovsynch or Ovsynch plus P4 are 2 feasible alternatives to increase P/AI of cows without a CL at the PGF injection of RD32. Supported by New York Farm Viability Institute project AOR12–012.