Quality of silage and silage effluent as influenced by storage of effluent in tower silos

Abstract

Silage effluent, normally considered a potential environmental pollutant, can be successfully fed to livestock, but must be stored from the time of drainage prior to feeding. In this study, effluent from ensiled direct‐cut grass was retained in closed‐drainage tower silos, such that silage and effluent were stored together but the effluent was released prior to the silage being fed. Silage quality was good, similar to that from a silo with normal open drainage. The quality of silage effluent from the closed‐drainage silo tended to be better than that of effluent stored in a separate tank. Decreased compaction of the ensilage mass, due to collection of effluent in the silo, led to a 13% reduction in the silo's crop capacity and 10% in its silage capacity, but no reduction in its total feed dry matter (DM) capacity (silage plus effluent). The total storage volume, however, was better utilized for feed DM when silage and effluent were stored together in the silo than when stored separately in silo plus tank. However, owing to problems caused by effluent leakage via trapdoors and small holes in the silo wall, the use of silos with open drainage and storage of effluent in separate tanks is recommended.

Key words:

• digestibility
• direct‐cut grass
• ensiling losses
• fermentation
• silo capacity
• storage volume