In prior research, using a combination inoculant containing homofermentative lactic acid bacteria and fibrolytic enzymes we showed an improvement in rumen DM degradation, lactic acid production and rate of pH decline, for alfalfa using small scale setting. The objective of the present study was to test the effectiveness of the inoculant on the quality of ensiled mixed cool season grasses (orchard, oat, mountain brome and Italian rye grasses) in a farm scale setting. Grasses were harvested and the windrows randomly assigned to either the control (Con) or inoculant (Trt). The Con was treated with water only and Trt was treated with an equal amount of water plus the inoculant. Control was baled, and wrapped first, followed by Trt. On d 86, 88, 90, 92, 94, 3 bales from each group were removed, weighed, core samples taken and composite samples prepared for analysis. Composite samples were analyzed for pH, lactic acid, DM, and NDF. Statistical analysis was conducted using a T-Test, on SAS v. 9.4. Initial DM did differ between Con and Trt (P = 0.03; 52.3 vs. 58.4 ± 1.9%) possibly related to temperature change (start 16°C, finish 32°C) during baling. Initial pH was not different between Con and Trt. Initial NDF was not different between groups (P = 0.15; 60.02 vs. 58.29 ± 0.72%). Final pH was not different between Con and Trt, either (P = 0.45; 5.24 vs. 5.36 ± 0.12). DM loss was numerically greater for Con, but not significant, either on kg/bale basis (P = 0.39; 91.7 v. 85.9 ± 12.5kg) or as a percent/bale basis (P = 0.32; 24.9 vs. 20.9 ± 3.0%). Lactic acid production was not different between groups (P = 0.14; 40.89 vs. 75.24 ± 19.88 µmol/g DM). There was, however, a significant difference in final NDF between Con and Trt (P = 0.04, 55.25 vs. 57.84 ± 0.81%). Whereas Trt showed greater NDF, Con had numerically greater DM loss, possibly indicating that Con lost more soluble nutrients during ensiling. Furthermore, final pH for both Con and Trt were above desired pH of 4.00–4.20, which could indicate that fermentation was in part inhibited by the high initial DM.