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Key references for the conservation of fermented forages

Solution name: Key references for the conservation of fermented forages

Aim: to produce and store quality fodders (grass and maize) through fermentation.


This solution identifies key points to know for producing quality silage and haylage:

– Silage quality partly depends on the silo. It must be cleaned before harvest and checked if waterproof.

  •  Forage must be harvested at an early stage of development. For Gramineae: at the end of the stem elongation (silage) or at the beginning of heading stage (haylage). For legumes, when they reach a 60 cm height during growth (silage) or at the very beginning of the budding stage (haylage).
  • For grass silage, the percentage of dry matters (MS) must be between 25% and 30%. Silage harvested this way shows the best ratio between “nutritional value/intake/good conservation”. It is best to dry over a day between the cutting and harvest. Maize is best cut when vitreous, with 30% of DM. For haylage, the ideal DM rate stands between 50% and 60%.
  • During harvest, a high-cutting height has a positive impact on the nutritional value, but there is less forage collected. For grass silage and haylage, the cutting height must change depending on the risk of contamination by soil.  For grasslands in good condition, we recommend a cutting at 7 cm. For maize, we recommend cutting at 25 cm (best trade-off between yield and quality).
  • A fine cut helps make compressing, conservation, and intake better. Long grass blades stimulate rumination, but they can cause mould growth.  Recommendations = Grass: 1.5 cm (+0.5 cm); maize: 0.5 to 1.5 cm depending on the DM. For maize, we recommend using a corn cracker if the DM rate exceeds 35%.

  • Start the harvest late morning to maximise the fodders’ rate of soluble sugars, and to stimulate the acidification of the silage, which makes storage easier.

  • For haylage, we recommend avoiding tossing the grass too much and to carefully calibrate the tools to prevent contamination by soil.

  • You can use preservatives to ensure the fodders’ good conservation while improving the fermentation process and preventing unwanted fermentation. Preservatives reduce overheating and post-fermentation when cutting the silage and limit DM-rich silage being wasted.

  • Good compression of silos plays an important role in ensuring the good conservation of silage. Compress the fodder to remove the air in it and create successive layers measuring 10 to 30 cm. The silo must be sealed as soon as possible using new equipment of good quality to ensure air- and watertightness.

  • For haylage, we recommend using large and good quality plastic. You should double the layers if the cut contains sharp blades (ex.: alfalfa with thick stems). We recommend organising the workload as best as possible to minimise handling, and to use the right bale grab when doing so. For storage, place the bales on their flat side, away from hedges to protect them from birds and rodents.

  • Regularly check the bales for holes or rips. If any, act quickly: It is important to not use those bails too soon. You should wait for 4 to 6 weeks before opening them.

    A flat surface of penetration on the silage prevents mould from appearing. During winter, cut 20 cm of silage per day, and 40 cm during summer. When cutting the silo, we recommend using a sharp bucket rather than a grab. Mild temperatures in spring can have a negative impact on the preservation of an opened silage.

Topic: Nutrition

Production:  Dairy / Meat

Animal Category: Adult / Lamb / Replacement

Issue:Conserve forage production (hay, silage…)

Level of Solution: Practical

Country: France






How to implement it

Consider as many of these elements as possible. It is important to be very familiar with the harvesting equipment, the state of the grassland (presence of rodents), harvested plants (whether they are rich in soluble sugars or not). Weather also plays an important role in the success of the harvesting process. Harvesting methods should therefore be adapted to weather conditions, especially the preservatives. Every single operation must be carefully carried out during the silos’ conception and the harvest. The bales’ size as well as the silos must meet the herd’s needs (silo face).

Expected benefits

Production and storage of good quality silage and haylage. Production and optimisation of the fodders’ nutritional value, a shorter drying time, and a shorter period of exposure to the sun, which can reduce the need for concentrates. Harvest when it is not possible to make hay, during the spring or in early autumn. Optimisation of the grasslands’ production (quality/quantity ratio) while increasing the number of production cycles and reducing their length. Reduction of fodders storage facilities’ size.

Prerequisites and/or limits

Successful fodder harvest and production depends greatly on the weather. Weather windows are often short and do not allow harvest or other operations to be carried out at the right moment.  Pests (voles) and bearing capacity of soil can contaminate the fodders with soil during harvest. Butyric acid spores, which are hidden in the soil have a negative impact on the fodders’ preservation: they cause strong smells, mould, and cause the bale to overheat, thus lowering the nutritional value of the silage. This results in less energy, less proteins, lower intake and, therefore, and a lower production level of the animal. Sheep are sensitive to the ingestion of low-quality silage or haylage, as they can develop serious health problems such as listeriosis.

Information Source / Useful links

Récolte et conservation de l’herbe – comment ça marche ? Avril 2011, Arvalis – Institut du végétal.

Guide Technique Ensilage – valoriser et sécuriser votre fourrage. Edition 2003 – Lallemand.

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