Among oxygen-limiting silo manufacturers, there is no uniform basis for measurement. Differences occur in volume measurement, due to the inclusion of varying amounts of the dome portion of the silo above the walls. Tonnage capacities vary due to the foregoing, plus the fact that various silage densities are used in the calculations.
One method of stating silo capacity for whole-plant silages, which eliminates some of the variation (particularly due to moisture content ) is in terms of dry matter (OM) capacity. Within certain limits it has been observed that a particular size of silo will hold a fairly constant amount of dry matter, regardless of the moisture content. Since the basis of ration formulation is dry matter, this method of stating silo capacities seems to be both practical and appropriate.