This study was designed to evaluate whether commonly used gonadorelin products that are commercially available in the United States have comparable ovulation and pregnancy per AI (P/AI) results in synchronized lactating dairy cows. A total of 1411 lactating Holstein cows receiving the Double-Ovsynch (DOV) protocol with the addition of a second PGF_2α (d 25) treatment (d 1: GnRH, d 7: PGF_2α, d 10: GnRH, d 17: GnRH, d 24: PGF_2α, d 25: PGF_2α, d 26-p.m.: GnRH, d 27: AI 16 h after last GnRH) for first postpartum AI were randomized to receive one of the following GnRH products throughout the Double-Ovsynch protocol: (1) Cystorelin (CYS, gonadorelin diacetate, n = 484); (2) Factrel (FAC, gonadorelin hydrochloride, n = 482); or (3) Fertagyl (FER, gonadorelin diacetate, n = 515). On d 17 and d 24 of DOV, a subgroup of cows (n = 487) were examined by ultrasound to identify whether ovulation had occurred following the 3rd GnRH injection in the DOV protocol (G17). Circulating progesterone concentration was also measured on G17 of DOV (presumably d 7 of the estrous cycle) in a subset of cows (n = 487) to evaluate the impact of circulating P4 on ovulatory responses. Statistical analyses were performed with the procedure Glimmix and Logistic of the SAS software (9.4 version). Proportion of cows ovulating at G17 tended (P = 0.07) to differ among GnRH salts (gonadorelin hydrochloride = 61.5% vs gonadorelin diacetate = 72.7%) but was similar across GnRH products (FER = 74.1% vs FAC = 61.5% vs CYS = 72.2%). In a further analysis, the logistic regression model indicated that predicted ovulation response to FAC was consistently lower than the other 2 GnRH products regardless of circulating P4 levels, although greater circulating P4 had a similar detrimental effect on ovulation across all GnRH products. Results on P/AI at 60 d differed across GnRH salts (P = 0.02) as well as commercial products (P = 0.04), in which P/AI was similar between FER (47.8%^b) and CYS (49.8%^b), but both were greater than FAC (42.0%^a). In conclusion, fertility following Double-Ovsynch was significantly lower for the hydrochloride-based GnRH product likely due to poorer ovulatory responses throughout the synchronization protocol.