Throughout this period, producers have sought less time-consuming and less difficult alternatives to these recommendations. Producers consider this thin layer as a small loss which can be sacrificed so as to avoid the labor of covering the bunker silo with plastic. This visible loss is only a portion of the loss which is occurring in the silo. When the blackened material is removed prior to feeding, it is referred to as visible waste.
Some covers allow precipitation to percolate into and through the silage.
That which percolates through the silage is called effluent. This effluent carries soluble organics, including organic acids, from the silage. These removed organics represent a dry matter loss. The reduction in organic acids causes the pH to rise. The higher pH makes the silage more easily decomposed by microbial activity.