The objective of this study was to evaluate the effect of supplementing calcium salts of linseed oil (AG-Ca; rich in linolenic acid (18:3 (n-3)) on the ovarian dynamics in dairy cows. In a 10-week assay, 38 primiparous and multiparous Holstein dairy cows (with 55 ± 18.1 DIM, 594 ± 96.8 kg of BW, 2.71 ± 0.4 of BCS, 2 ± 1.4 lactation number and milk production of 38 ± 9.4 kg/d) were used in a complete randomized block design. Cows were assigned to one of 2 treatments (O3: AG-Ca supplementation (0.85 kg/d AG-Ca) or CON: no fat) and were blocked by DIM, number of lactations, BW, milk production and corpus luteum presence. Isoenergetic diets were formulated to meet requirements of a Holstein dairy cow of 650 kg BW with 40 DIM, producing 40.0 kg/d of milk with 3.6% fat (NRC, 2001). A timed artificial insemination (TAI) at 80 DIM preceded by a PreSynch (14/12) + OvSynch protocol was implemented for the first service and ovarian dynamics were studied during the OvSynch and TAI. A portable ultrasound Aquila Pro (Pie medical) B mode in real time, with lineal transducer of 8 MHz, was used to determine the presence and sizes of ovarian structures (follicles (FOL) and corpora lutea (CL)), and the gynecological condition. Supplementation does not change milk production and energy status of the cows (Iorio, 2018). After PreSynch, 72.22% of cows of O3 and 75% of CON, presented CL. Linseed oil supplementation had neither effect on the emergence of a new follicular wave (O3: 2.22 ± 1.20 d vs. CON: 2.78 ± 1.79 d; P = 0.217) nor the size of preovulatory follicles (O3: 16.66 mm vs. CON: 16.27 mm; P = 0.707). Conversely, linseed oil supplementation had effect on the volume of the main CL 6 d after TAI (O3: 17.60 mm vs. CON: 13.67 mm; P = 0.0218). Data were analyzed using the MIXED of SAS with significance declared at P ≤ 0.05. These results probably highlight the importance of linseed oil supplementation on FOL and CL development, which may lead to better pregnancy indexes.