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Minimising silage losses

Minimalising Silage Losses

Approximately 38.6 million tonnes of grass silage were made in 2008 in the UK.

The idea behind the production of silage is to render the forage preserved for future use with minimal loss of nutritive value and minimal spoilage.



Nutrient loss is an inevitable consequence of the ensiling process. This can vary greatly depending on harvesting, clamping and feeding. The average dry matter losses in grass silage are typically 25%, but can range from 10 to 70%. These losses are reflected in the compensatory concentrate feed required and can be up to £60 a tonne.

Minimising Harvesting Losses:

  • Mow in the afternoon when the sugar levels are at their highest and moisture levels are at their lowest in the grass 


  • Cut at the correct time with regards to crop maturity and weather conditions
  • Mow at a height of 5cm, then spread the grass evenly and rapidly – within an hour to ensure optimum DM content
  • Adjust the chop length according to grass DM %:
    • 1.5 – 2cm for 28-35%
    • 2 – 2.5cm for 20-28%
    • >2cm for <20%
  • Ensure rapid wilting (no more than 24 hours)


Minimising Clamp Losses:

To shorten the first stage of fermentation (aerobic) to allow anaerobic preservation to occur:

  • Fill, consolidate and seal the clamp ASAP
  • Thoroughly roll the clamp and ensure full consolidation before the next load is added 
  • Cover with a double layer of sheeting:
    • Thin flexible layer in contact with the crop
    • Thick protective layer on top
  • Weigh down the sheeting to remove as much air as possible but avoid using tyres!!
  • Leave the clamp undisturbed for at least 3 weeks
  • Allow adequate and appropriate drainage of effluent from the clamp


Minimising Feeding Losses 

  • When the clamp is opened, secondary aerobic fermentation occurs and may reduce the dry matter content by more than 10%:


    • Remove the silage evenly, with clean cuts from across the clamp face – a shear grab is ideal
    • Remove the entire silage face in fewer than 5 days
    • Feed cattle from clean bunker/troughs – remove any dirty/mouldy/uneaten silage