Silage troubleshooting in grass silages

Grass silage with moulds

There are many potential reasons why grass silage may heat, be affected by mould or fail to ferment properly. The following pages support you in analysing vulnerabilities in silage management and help you identify potential causes and solutions.

Reheating/mould immediately underneath the film

Possible causes

  • Holes in the silage film, e.g. caused by birds or mice
  • Insufficiently strong silage film
  • No oxygen barrier
  • No sand bags as cross lines


Solutions

  • Use oxygen barrier
  • Use main silage plastic that is at least 150 µ thick
  • Use silage netting to protect against mechanical damages
  • Use sand bags as cross line on the silage face to prevent air from entering

Reheating/mould at the upper silo face

Possible causes

  • Inadequate compaction
  • Pick-up rate (chop length, deposited layers) and silo geometry (i.e. silo size) do not match
  • Incorrect removal technique and overfilling of silage clamps: loosened, rough silage face


Solutions

  • Improve compaction: Reduce the pick-up rate per unit of time if the silo surface is not yet large enough
  • Avoid “ripping” harvesting techniques

Reheating/mould about 20 cm below the surface

Possible causes

  • Excessively deep layers deposited at the top: This prevents deep compaction (max. 30 cm, depending on tyres)
  • Silage layer excessively contaminated with soil and dirt
  • The top layer is often unaffected as it cools and temperatures are therefore too low for moulds or yeasts to grow


Solutions

  • Max. 15 – 20 cm layer depth
  • Maximise deep compaction during rolling: maximise tyre pressure; avoid using dual tyres
  • Harvest clean Silage: avoid setting harvesters too low, increase cutting height

Reheating/mould in the middle of the silage

Possible causes

  • Excessively dry substrate layer: old, excessively wilted material
  • Excessively deep deposited layers
  • Insufficiently chopped material


Solutions

  • Max. 15 – 20 cm depth of deposited layers
  • Avoid introducing over-mature and/or excessively wilted material into the middle of your silage: instead ensile separately (round bales, square bales, separate silo) or deposit in thin layers at the very bottom of the silo

Reheating/mould randomly distributed

Possible causes

  • Insufficiently chopped or distributed over-mature substrate (in combination with inadequate compaction)
  • Inhomogeneous silo filling, presence of cavities, slip
  • Inadequate grassland management, e.g. harvest residue from the previous cut (rough-stalked meadow-grass)

Solutions

  • Chop over-mature material very short (2 cm)
  • Fill silos evenly: avoid “cavities” resulting from unloading large forage quantities
  • Prevent slip of harvesting vehicles on Silage by pulling up the compaction tractor
  • Avoid harvesting residue from the previous cut: remove rough-stalked meadow-grass with a harrow and discard

Reheating/mould around the edges

Possible causes

  • Incorrect filling of silage clamps (sloped outside edges): poor compaction along edges
  • Ingress of air or water, e.g. if no side wall or oxygen barrier is used


Solutions

  • Rolling right up to the silo wall
  • Use side wall and oxygen barrier

Silage smells of butyric acid

Possible causes

  • High contamination (crude ash) of harvested material due to attached soil or late fertilisation with liquid manure before the harvest
  • Extensive fertilisation: shortage of nitrate in plants as a natural inhibitor of clostridial growth during the ensiling process
  • Ensiled material too wet: fermentability coefficient too low


Solutions

  • Clean harvest, reduce soil contamination
  • Adjust fertilisation
  • Review silage additive used

Rotten, slimy layer on the surface

Possible causes

  • Holes in the silage film, e.g. caused by birds or mice
  • Long delay in covering silage
  • Pockets of air between the film and silage


Solutions

  • Cover the silage as soon as rolling has been completed
  • Use oxygen barrier
  • Use main silage plastic that is at least 150 µ thick
  • Use silage netting to protect against mechanical damage
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Silage tips for grass
Grassilo  Gut  Huelsenberg  Kaese  Haemmerling 2014
Correct silage management is the basis for high silage quality. Find useful tips on ensiling grass on these pages.