Minimising impurities in forage

When harvesting forage, it is important to minimise impurities in the feed. Impurities not only have a negative effect on feed quality, but also on milk and meat production and therefore a farm’s profitability.  

In practice, one of the main problems is soil particles in the forage. This can compromise good storage properties. In addition, it can also negatively affect the nutritional feed value, so it is less easily digested by the cows. Particularly in periods of wet weather, baling the grass properly can be a huge challenge. Not only the grass, but also the ground has a low traffic bearing capacity and can be severely affected. This is because sunlight and air cannot penetrate down to the soil. A heavy crop of flattened grass must also be cut short, which brings a high risk of trapping soil particles in the harvested forage. 

Impurities in forage cause lower milk and meat production 

Soil contamination in forage can be considered as external ash content as it adds no nutritional value for the livestock. Higher ash content may also lead to reduced efficiencies in milk and meat production and therefore reduced overall economic efficiencies. It can also lead to quality losses during storage and increases the risk of heating in the bale, which would then have to be compensated for by adding extra concentrates into the ration. The forage can become less palatable for the livestock  so their overall intake may reduce. 

The economic impact of forage contamination can be considerable. For example; forage that contains 4% of soil impurities represents an energy loss equivalent to approximately €48 per hectare. Therefore the decrease in the cow’s energy intake due to impurities is equivalent to €27 per cow per year.

Adjust machinery to prevent impurities in forage

Several factors are important when mowing, tedding and raking grass. First, ensure that damage caused by field operations is avoided. Mowers, tedders and rakes must be levelled on a flat surface. The working height must be determined and set in the field. Do not cut too short, but maintain a cutting height of 7 centimetres, so that later during harvesting, the baler will not need to be adjusted too low to pick up the grass.