Knowing the quality of the silage on your farm is vital to ensure that maximum herd performance is achieved through forage.

The housed period is getting underway on many farms across the country, with the wet weather impacting on grazing conditions.

Harvesting of fodder was also a challenge on most farms this year, so it is important to have an understanding of the quality of the fodder within the pit.

For herds that are producing winter milk, knowing the quality of silage is vital. Without an understanding of fodder quality, it is impossible to know the concentrate feeding rates required.

While for spring-calving herds, knowing the quality of feed isn’t as important. However, for these herds, some high-quality forage will be needed, and it is always good to know just how good it is.


When getting your silage tested there are a number of areas to consider. A dry matter digestibility (DMD) test is a reliable and accurate test of a forage’s feeding value.

This result is used to estimate energy value, expected milk yields or liveweight gain, and required supplementation rates.

Young perennial ryegrass swards cut for silage after six weeks of growth should have a DMD percentage of 75-80%, while older, stemmy swards when cut would have a DMD percentage of 60-65%.

There are also other areas of the results which need to be considered, such as:

  • Dry matter (DM);
  • Crude protein;
  • Metabolisable energy (ME).


DM is the amount of silage material once water has been removed. Generally, the higher the figure the better, as this will increase intakes.

You should target a DM of 20% or higher; this will increase intakes in cows.

Crude protein

The crude protein percentage reflects the quality of the grass at harvest, with young, leafy grass having values of over 15% and stemmy grass having values of less than 10%.

Protein levels in silage made in early summer are usually higher than silage made in mid-summer.


ME is the usable energy of the silage. Young, leafy grass should have a high ME value, while hay would have a low ME value.

Winter diets

Without having an understanding of the quality of your silage, formulating a winter diet is almost impossible.

Working off last year’s diet is not advised as the quality of the forage is likely going to be different and there may be different nutritional requirements.

Farmers should aim to maximise the amount of milk produced from forage and thus reduce the amount of bought-in supplementation.

Knowing how much concentrates are required can only be achieved when you know the quality of the silage on your farm.

Winter milk is currently a low-margin game and feeding concentrates that are not required should be avoided.