We tested (1) a shortened version of Ovsynch (OVS: GnRH1–7 d-PGF_2α-24 h- PGF_2α-32 h-GnRH2–16 h-AI) that excluded GnRH1 for resynchronization in cows bearing a corpus luteum (CL)at non-pregnancy diagnosis (NPD); (2) the value of including progesterone (P4) + OVS in absence of a CL compared with presence of a CL + OVS; and (3) the accuracy of detecting a functional CL by transrectal ultrasonography. Lactating Holsteins (n = 1,589) in 3 herds were enrolled in 3 treatments at NPD (32 ± 3 d after AI). Cows bearing a visually detected CL were assigned randomly to OVS or Short Synch (SS; PGF_2α-24 h-PGF_2α-32 h-GnRH2–16 h-AI), whereas cows with no CL were assigned to OVS + CIDR insert (CIDR). Blood collected at NPD (d 0) determined accuracy of treatment assignment based on P4 (functional CL cut point >1 ng/mL). In 1 herd, ovaries of 108 SS cows were scanned at d 0, 2 d after PGF_2α, and 6 d after AI and on d 0, 7, 9, and 16 in OVS (n = 97) and CIDR (n = 68) cows to determine follicle diameter and ovulation risk. Treatment contrasts were made: OVS vs. CIDR and OVS vs SS. Ovulation risk after GnRH1 was greater (P = 0.04) for CIDR (40.3%) than OVS (27.1%) cows. Dominant follicle diameter before PGF_2α was greater (P = 0.05) for SS than OVS cows and P4 was less (P < 0.01) in CIDR compared with OVS cows. No differences were detected for luteolysis after PGF_2α (>96.6%) and ovulation risk after GnRH2 was 94.2, 91.7, and 85.2% for SS, OVS, and CIDR, respectively. Accuracy of treatment assignment was 59.6, 79.5, and 82.4% for CIDR, OVS, and SS cows, respectively. Technicians were more (P < 0.01) accurate in detecting a functional than non-functional CL. Pregnancy per AI (P/AI) in all cows was greater (P = 0.03) when P4 was ≥1 ng/mL at d 0. With herd as a random effect, P/AI was greater (P = 0.02) for OVS than SS but did not differ from CIDR at 32 d (29.6% [n = 644], 21.5% [n = 676], and 25.9% [n = 269]), respectively. When cows within treatment were retrospectively categorized based on P4 cut point, P/AI did not differ among treatments (30.2% [OVS; n = 511], 27.4% [SS; n = 562], and 25.3% [CIDR; n = 164]). Short synch is a viable option when CL status can be accurately detected.