Silage Loss & Count the Dry Matter You Keep

The tool first finds the dry matter going in: fresh weight × dry-matter percent. It then applies the loss: dry matter retained = DM in × (1 − loss%), and dry matter lost = DM in × loss%. The silage coming out as fresh tonnes is the retained dry matter scaled back up by the silage dry-matter percent. Every figure follows directly from those balances.

Ensiling is a controlled fermentation, and fermentation burns sugars to make the acids that preserve the crop, releasing carbon dioxide and heat — that is real dry matter gone. On top of that, effluent can carry away soluble nutrients, and any air left in the clamp lets spoilage organisms eat more. So some dry-matter loss is unavoidable; the goal is to keep it small.

Well-made silage in a sealed clamp or bale often loses around 10–15% of its dry matter from field to feed-out. Poorly compacted, slowly sealed or badly fed-out silage can lose 20–30% or more. The figure you enter should reflect your system; the tool then shows the tonnes of feed that loss actually costs you.

Slow filling and sealing, loose compaction that traps air, ensiling too wet (which increases effluent) or too dry (which prevents good packing), warm weather, and a slow feed-out face that re-heats. Each of these lets more dry matter be respired away or spoiled. Reducing them is the cheapest way to put more feed in front of stock.

Dry matter is what is left after all the water is driven off — the actual feed substance. Fresh forage is mostly water, so two clamps of equal fresh weight can hold very different feed if their dry-matter percent differs. Losses are measured on a dry-matter basis precisely because that is what feeds the animal, not the water.

To convert retained dry matter back into silage tonnes, yes — the silage out depends on the dry-matter percent of the conserved feed, which is usually close to the crop you put in. If you only want the dry-matter figures you can read those directly; the silage-out tonnes is the extra step that turns dry matter back into a clamp weight.

Yes — grass, maize, wholecrop and legume silages all follow the same dry-matter balance. Only the numbers change: maize ensiles at a higher dry matter and often lower loss, while wet grass can lose more to effluent. Enter the values for your crop and the calculation holds.

Fill and seal fast, compact hard in thin layers, ensile at the right dry matter, use an effective film or inoculant, and feed out across a tight, fast-moving face. Each step cuts the dry matter that ferments away or spoils, so the retained tonnes the tool reports go up.

They are solid planning figures from your inputs. Actual loss depends on the season, the harvest and how the clamp is managed, so treat the result as a working estimate. Weigh loads and sample dry matter where you can, and use the tool to compare scenarios and set realistic feed budgets.