The dry matter (DM) of the forage is instrumental in defining the treatment, harvest methodology and compaction.
When below 30% DM there is a significant likelihood of producing effluent, the wetter the forage, the greater the risk of effluent production. Effluent is an issue because it contains protein, energy in the form of sugar etc. This reduces the feed value of the forage, as well as being environmentally challenging because of its high acidity and oxygen demand and it also saturates the base of the bunker and creates an ideal environment for the growth of clostridia and other spoilage organisms. As such, you should always try to wilt to 30% DM if possible. As the DM of the forage increases then the amount of effluent that will be produced per ton of forage decreases. If not possible, then at harvest you should do everything practical to reduce effluent production such as:
- use sharp knives
- set for long chop length
- do not overcompact the silage at ensiling. Train wheel compactors should not be used under 30% DM
- if DM is below 25% – ensile in thicker than normal layers, but take care not to build the bunker/pile too high as ‘slippage’ of the silage can occur
- use a challenge-specific inoculant