Improving silage quality: 6 steps from field to pit

Your cows eat what you put in the pit all year round. You can't control the weather, but from the soil to the cover there is a lot you can control yourself. With these 6 steps you get more quality out of your grass and maize.

Why is silage quality so important?

About three quarters of a dairy cow's ration is forage. On the farms of Koeien & Kansen, a network run by Wageningen University & Research (WUR), this was grass silage, fresh grass and maize together in 2023; concentrates and dairy by-products made up 23%. Every step that improves quality shows up in what your cows eat and in your bulk tank. For an overview of the whole process, see the guide making and preserving silage.

How do you improve your silage quality? 6 steps

1. Fertilise for good soil

Quality starts with the soil. With enough organic matter in the soil, grass grows better. Fertilising feeds the land and gives a high grass yield of good quality. If your land suffers from drought, see what you can do in drought on grassland.

2. Keep a good sward

A good sward is free of weeds, has good grass varieties and produces grass that is high in sugar. More sugar means more energy and better digestion for your cows. In the pit, the good bacteria can then grow better, which helps prevent heating and mould. Why sugar matters so much is explained in grass sugar content.

How to work on your sward:

• Harrow in spring. This removes the poor grasses.
• Let strong grass varieties fill the open patches: they get plenty of light there.
• Overseed in autumn.

3. Set the cutting height correctly

If you cut your grass too short, you may get a good yield, but the next cut suffers. You cut away the growing points and the grass grows back more slowly. The growing points are at about 5 cm, so cut above that. We recommend a stubble of 6 to 7 cm (WUR gives 5 to 6 cm). Cutting higher also helps keep soil out of the feed.

4. Ensile in layers for a consistent ration

A stable ration is good for your cows. One way to get it is to ensile in layers in the same pit. You put the second cut on top of the first, the third on top of that, and so on. The first cut is usually the most palatable. When feeding out, you cut through all the layers, so your cows are eating some first cut all year round. That way you feed a consistent ration.

5. Compact carefully

A walled silage pit is a good way to limit heating: the feed is enclosed between the walls. But the rolling has to be done well. Many farmers and contractors give it too little attention.

• Roll evenly, especially at the edges.
• Spread thin layers. A thick layer is stiff and hard to compact. Air stays in and heating gets a chance.

More tips are in silage compaction tips. For maize, you will find specific tips in improving maize silage quality.

6. Cover tightly

Covering is the last step to hold on to your quality. The edges and the top layer are the weak spots of a silage pit. That is where the risk of heating and mould is highest. Roll the silage evenly, finish the top smooth and slightly rounded so no water stays on it (WUR), and make sure the cover is tight along the sides too. With Silage Safe you make the silage rounded, so the covers pull the plastic tight over the whole pit and water runs off through the drainage. How to do this step by step is explained in covering a silage pit. See how Silage Safe tensions the covers towards each other on our product information page. "When it comes out from under there, it's just better silage," says Sybren Nauta from Itens about his silage under Silage Safe.

What does a silage analysis tell you?

A forage or silage analysis shows you in black and white how your silage has turned out. It gives you the dry matter, the feed value and the pH, among other things. Two figures from Eurofins Agro tell you a lot about your ensiling work:

• Preservation index: runs from 0 to 100, the target is above 80. Silage that is poorly preserved can't be improved afterwards. But the index does help you decide which silage to feed to which animals.
• Sensitivity to heating: between 35 and 50 the silage is sensitive to heating, above 50 very sensitive. Then it helps to put more weight on the cover and raise the feed-out rate.

That way, every cut teaches you what to do differently next time.