Abstract An experiment evaluated forage value of crested wheat grass (CWG) harvested from Western Nebraska over a 2-year period (2019-2020). Two large pastures, comprised of 95% CWG, were divided into 13 paddocks (34.4 ha, 3 paddocks and 42.5 ha, 10 paddocks). Within each pasture, 2 paddocks were assigned at random for sampling. Forage samples were collected twice each month from 2 random locations within assigned paddocks by hand clipping forage within a 0.25m2 quadrant at ground level. For each year, samples were composited by pasture and month. Samples from 2019 (n = 10) were harvested in May, June, July, August, and September while 2020 samples (n = 8) were harvested in May, June, July, and August due to drought conditions. Local precipitation from May 1st to September 30th was 552.7 mm for 2019 and 150.1 mm for 2020 with a 10-yr average precipitation of 350.0 mm. Cattle were stocked at 4.2 hectares per steer using a rotational grazing system. Samples were freeze dried and ground to a 1mm particle size to evaluate in-vitro dry matter disappearance (IVDMD, % of DM), and in-vitro organic matter disappearance (IVOMD, % of OM). Orthogonal contrasts were used to analyze changes in forage quality over time with month and pasture as fixed effects (glimmix procedure of SAS). Forage quality quadratically decreased over the growing season in 2019 (IVDMD, P = 0.02 and IVOMD, P < 0.01). In May, 2019 CWG averaged 54.0% IVDMD and 60.4% IVOMD and decreased to 37.0% IVDMD and 43.3% IVOMD by September 30th. No significant differences in IVDMD (P = 0.57) or IVOMD (P = 0.53) between months were detected for samples collected in 2020 averaging 43.1% IVDMD and 46.8% IVOMD. When precipitation is not limiting CWG, forage quality is greatest early in the growing season and decreases as it matures.