Improving uterine environment and ovarian function may lead to improved reproductive efficiency in dairy cattle. The objective of this study was to observe the effects of Saccharomyces cerevisiae fermentation products (SCFP) on ovarian dynamics and uterine environment. Multiparous Holstein cows (n = 101) were supplemented from 30 d before calving to 65DIM. Treatments were CON (control: no supplement; n = 32), XPC (14 g/d Diamond V Original XPC; n = 23), NTL (19g/d NutriTek; n = 21), and NTH (38 g/d NutriTek; n = 24). Ultrasound (US) was performed in the reproductive tract of cows daily from 7 DIM until the dominant follicle reached 16 mm in diameter. The total follicular growth was measured from 1st US until aspiration and the follicle size at aspiration. The US continued biweekly until 65DIM. Uterine fluid was harvested at 30 DIM via Foley catheter that was inserted into the uterine body and 20 mL of saline was flushed into the uterus and extracted. Specific gravity and protein content values were obtained via refractometer. Swabs of the endometrium were obtained at 15 and 30DIM, streaked onto slides, stained, and scanned using whole image scanning. Polymorphonuclear neutrophils (PMN) were counted and a percentage was calculated. Statistical analysis was performed using the MIXED procedure of SAS. Contrast statements were CON vs XPC, CON vs NTL, and CON vs NTH. No differences (P > 0.15) were observed for total follicular growth and follicular size at aspiration. Follicles from cows fed CON (20.09 ± 1.2 mm) were smaller (P = 0.01) at 65 DIM than cows fed NTL (24.87 ± 1.4 mm), and tended to be larger than cows fed XPC (17.04 ± 1.4 mm; P = 0.11), and NTH (17.08 ± 1.4 mm; P = 0.11). Cows fed CON (0.25 ± 0.08 g/dL) had higher (P = 0.05) uterine protein content than cows fed XPC (0.022 ± 0.1 g/dL). Statistical differences were not observed for lavage specific gravity (P > 0.89). Cows fed CON (19.3 ± 3.4%) had lower (P = 0.05) PMN than cows fed NTL (30.1 ± 4.4%) and XPC (30.76 ± 4.3%, P = 0.04). Supplementation of SCFP increased follicular size at 65 DIM and the PMN content in the uterus, possibly leading to better reproduction and immunity.