Estimated reading time: 6 minutes

Losses

Producing silage of excellent quality is a demanding task at every stage: from cultivation to use in feeding. A key factor is ensuring and maintaining oxygen-free storage conditions. This is one of the main challenges and can cause the greatest losses in dry matter (DM), nutritional quality, and feed hygiene. These losses are unavoidable but can be reduced. In the field, losses range between 1 and 5% of DM; during conservation and storage between 4 and 100% (rendering it unusable as feed); and during feeding between 1 and 7% of DM. These losses often go unnoticed or are considered “normal.” However, they can be positively influenced through good silage management. This includes an appropriate chop length, the use of silage additives, proper compaction, rapid filling and covering of the silo, suitable silage films, and proper feed-out techniques.

But how do these losses affect the farm’s profitability?

Losses in figures

The potential to minimize losses is significant—not only in terms of dry matter volume, but also in terms of nutritional value and palatability of the produced silage. Undesirable fermentation, caused by microorganisms that develop in the presence of oxygen and at a pH above 4.2, leads to enormous losses, even to the point where the feed becomes unusable. Valuable nutrients are converted into CO₂, H₂O, alcohol, heat, and odor compounds that negatively affect daily forage intake. As a result, milk production also declines.

Fermentation losses have the greatest impact on both the nutritional and economic value of silage. With good fermentation, average DM losses are around 8%.
If they increase to, for example, 12%, the energy content in maize silage drops by 0.2 MJ NEL/kg. This seemingly small reduction results, per hectare, in 590 kg less DM and 6,653 MJ less net energy for lactation (NEL) than was originally stored in the silo (45 t fresh matter/ha, 33% DM).

Economic impact on milk production

Good silage management pays off, as the following calculation shows: If DM losses during fermentation increase from 8% to 12%, then, per hectare of maize, 6,653 MJ NEL and 304 kg crude protein (CP) are missing. This energy must be compensated with concentrate feed. A 20-IV dairy concentrate costs about 5 cents per MJ. The energy contained in silage with 6.8 MJ NEL costs around 3 cents per MJ NEL based on standard contribution margin calculations. This means that energy worth about €200 is lost during ensiling, and an additional €333 must be spent to compensate with concentrate feed.

The economic losses affect not only nutrient values but also the amount of milk produced from forage. With a feed ration of 40% grass and 60% maize at 6.8 MJ NEL (with 8% losses) and an intake of 14 kg DM per day, a cow can produce 17.5 kg of milk. With 12% losses, the same feed—now with 0.2 MJ NEL less in the maize silage—only supports 17 kg of milk. If the declining quality also reduces DM intake to, for example, 13.5 kg, milk production from forage drops further to 16 kg.

Higher benefits

In addition to the potential for more milk from forage, the efficiency of land use also increases. Assuming an area of 50 hectares at 33% DM, reducing DM losses by just 4% yields the same amount of usable silage from only 48 hectares. This is the difference between average and high-quality silage—with a major impact on both finances and the environment.

Improvements in analysis results

Alongside DM losses, changes can also be observed in certain analytical values. Differences have been found from storage through to after opening the silo, especially in systems without cross barriers and with films lacking an oxygen barrier. The constant presence of oxygen initially leads to explosive growth of yeasts and molds. Later, putrefactive bacteria develop. These microorganisms break down so much sugar and lactic acid that the relative proportions of analytical parameters such as aNDFom, starch, and crude ash increase.

An example: initially, maize silage (1,000 g DM) contains 40% aNDFom (400 g) and 36% starch (360 g). Assuming a 5% DM loss due to air exposure, the remaining amount is 950 g DM. The aNDFom content increases to 42%, and starch to 38%.

Optimization brings success

The goal is to preserve the nutrients delivered from the field under the cover or to convert them into valuable end products. All efforts toward excellent silage management pay off. In particular, fast and effective fermentation and secure storage lead to significant positive effects—both financially and ecologically.