The objective of Study 1 was to determine the effect of drying method on nutrient composition in corn silage (CS). There were 49 CS selected and split into 4 fractions. Two fractions were dried in an HVLT80 oven (O) developed by Cumberland Valley Analytical Services and the other 2 were dried in a microwave (M). Fractions were ground to 1mm and analyzed via NIR for ADICP, NDF, and starch. There were no differences between O and M in DM (P = 0.79), aNDFom (P = 0.87), and starch (P = 0.11). The ADICP was lower for O vs. M (0.43 vs. 0.79%DM, respectively, P < 0.0001), suggesting M causes heat damage. The objective of Study 2 was to determine the effects of drying method on particle size and in situ washout. Three corn silages were split into 2 fractions (O and M), and ground to 4mm. There were no differences between O and M for DM (P = 0.37), aNDFom (P = 0.69), or starch (P = 0.81). Mean particle size (MPS) was measured by shaking for 10 min in a Ro-Tap and 0.5 g was weighed into 5 × 5 cm Dacron bags with a pore size of 50 ± 10 µm in quadruplicate. Dacron bags were soaked in warm water for 10 min, rinsed in cold water, and washed in a washing machine. They were dried overnight at 55°C, weighed, then residues remaining was measured. Although the proportion of particles that passed through the 53-µm screen was not different between O and M (1.36 vs. 0.95%, P = 0.49), the MPS was smaller for O vs. M (459 vs. 533µm, respectively, P = 0.006). The DM washout was higher for O vs. M (46.1 vs. 27.4%, respectively, P < 0.001), and so was starch washout (62.8 vs. 39.7%DM, respectively, P = 0.01). Microwave drying corn silage resulted in heat damage and increased particle size, perhaps by gelatinizing starch granules, making it an unsuitable drying method. Both oven and microwave drying samples result in high washout of DM and starch for in situ. More research is necessary to evaluate laboratory methods for starch digestion.