Utilization of enzymes have been reported to improve feedstuff quality for dairy cows. The objective of this study was to evaluate 2 corns, Flint (F) and Floury (D); 2 particle sizes, grinded Fine (Fi) or Coarse (Co); application of 3 enzyme combination, amylase (A), protease (P) and both (AP); during 3 times of ensiling (TP) at 1, 3, or 5 mo in a complete randomized design resulting in 36 treatments. Each of the 5 silos for each treatment (replicates) consisted of 1kg of corn at 35% moisture and were stored in vacuum sealed bags at environmental temperature. Enzymes used were 650 g/t of amylase and 200 g/t of protease or the combination of the 2. Corn weight, pH and temperature were measured at time of bag opening. Samples were analyzed for starch, crude protein (CP) and prolamin concentration. Statistical analysis was performed using the MIXED procedure in SAS. Corn F had higher (P < 0.001) CP (9.52 vs. 7.61%DM) and prolamin (9.70 vs. 8.3 2%DM) before ensiling than D. On TP5, F had increased prolamin concentration (7.95%DM, P = 0.003) than D (4.91%DM). Corn F had lower weigh variation (11.34 vs. 12.12 g, P < 0.0001), lower starch concentration (65.03 vs. 66.63%DM, P = 0.01) and lower NFC (P < 0.0001) than D. Particle size Co had lower DM (29.28 vs. 29.41%; P = 0.04), higher weigh variation (12.12 vs. 11.34 g, P = < 0.0001) and higher pH (4.07 vs. 3.98, P < 0.0001) than Fi. Enzymes P and AP had lower prolamin concentration for A (6.09%DM), P (4.62%DM) and AP (4.92%DM, P < 0.0001); for starch, A had lower concentration for A (64.40%DM), P (65.30%DM) and AP (67.80%DM, P = 0.0002). Enzyme A had lower NFC, for A (8.75%DM), P (8.86%DM) and AP (8.89%DM, P < 0.0001). Corn weight increased with time 1.73g in TP1, 11.4g inTP3 and 22.02g in TP5 (P < 0.0001). Corn CP decreased (P = 0.04) with time ensiled from TP1 to TP 3 by 0.35%DM. Prolamin concentration changed (P = 0.01) during time of ensiling, 5.19, 4.0 and 6.43%DM for TP1, TP3 and TP5, respectively. In conclusion, P seemed to have reduced the matrix starch protein. Small particle size, enzyme and time ensiled, made F better feed but not as good as D.