OXYGEN INFILTRATION FROM HORIZONTAL SILO UNLOADING PRACTICES

Three bunker silos (two corn, one alfalfa) were unloaded with both a s kid-steer loader and a silo unloader which milled the face. Gas, tempe rature, and core samples were taken from each silo at four heights (50 cm from floor and top, two intermediate locations) and four depths fr om the face (12.5, 25, 50, 100 cm). Oxygen levels in the gas samples w ere 1.1 to 2.2 percentage units on a volume basis higher on the skid-s teer side, resulting from the increased surface area (8, 10, and 26% f or the two corn and one alfalfa silos, respectively) and porosity of t he silage at the face (4, 29, and 92%, respectively) caused by this un loading scheme. Aerobic microbial counts were low in all three silos. However, yeasts and acetic acid bacteria were higher in the skid-steer core samples. In the alfalfa silo and the corn silo sampled in summer , total fermentation products were 22 and 7 g/kg DM lower in the skid- steer core samples, respectively, suggesting somewhat higher aerobic l osses with this unloading method. Overall, differences in the characte ristics of the silages removed by the two unloaders in this study were small.