Harvest management

When you turn pasture into silage, you always lose some weight (drymatter) and some quality.

Silage losses start when pasture is cut. Sugars and protein in the pasture are broken down by enzymes and bacteria. Losses decrease quality as well as quantity because it is the most highly digestible components of pasture which are broken down first5.

The amount of drymatter lost during the ensiling process, and where the loss occurs, will depend on the drymatter of the pasture you ensile and the quality of your harvest management.

Typical losses are shown in Table 2.

Table 2: Typical pasture silage drymatter losses5
 Drymatter % at ensiling  Drymatter loss (%) in:    
  Field     Fermentation Effluent Heating
20% 2% 8-10% 3% 0% 14%
30% 5% 6% 1%  1% 13%
40% 10% 5% 0% 3% 18%
50% 15% 7% 0% 5% 27%

Field losses occur as sugars are lost from cut grass through respiration. When pasture is drier more is likely to be lost as it is broken up or blown away. Leaving pasture in the field to dry for longer also increases the risk of rain damage.

To minimise silage losses:

  • Harvest after 1 - 2 days of sunny weather to ensure good sugar levels in the pasture.
  • Minimise wilting time by cutting silage in the morning of a sunny day.
  • Avoid wilting for more than 24 hours.
  • Make sure that dirt is not harvested or carried into stacks on the wheels of compaction vehicles.
  • Use a quality silage inoculant

5DairyNZ farmfact 1-44. Losses when making pasture silage.