Silage feed-out rate: how many metres per week?

Once you open the pit, the silage face is exposed to air every day. If you move through the feed too slowly, it warms up and heating and mould get a chance. A steady feed-out rate is one of the simplest ways to keep your silage in good condition, even if your pit is actually too high or too wide for your herd.

What is the feed-out rate?

The feed-out rate is how fast you move through your silage pit: the number of metres you take off the silage face each week. A pit you have just opened gets oxygen at the face. The longer the same layer of feed is exposed to air, the more time yeasts, moulds and bacteria have to get to work.

Why does the feed-out rate matter for your silage?

• Less heating: the shorter the silage is exposed to air, the less time the feed has to warm up. More about this in preventing silage heating.
• Fewer moulds and harmful bacteria: the feed is exposed to oxygen, water and warmth for a shorter time. See also the causes of mould in silage.
• Better intake: fresh feed is more palatable, so your cows eat better.
• Higher feed value: with fewer moulds and bacteria, more feed value stays in your silage. What a heating silage face costs you, you can work out in calculating silage losses.

How many metres per week should you feed out?

We recommend a feed-out rate of at least 1.5 metres a week in winter and at least 2 metres a week in summer. In summer it is warmer, so the silage warms up faster and bacteria and moulds grow faster. That is why you move through the pit faster then.

This applies to grass and maize. Maize silage is known to be prone to heating. So with maize silage, make sure you reach at least this rate, and go a bit faster in summer.

With Silage Safe you can easily open a 2-metre section when feeding out. That fits this feed-out rate well. Wiljan Ten Hove from Kamperveen: "Within a few seconds you have a few metres of the pit open." See how the system works on our product information page.

What else should you take into account?

• The season: in warm weather the silage warms up faster and bacteria and moulds grow faster.
• Compaction: if the silage is less well compacted, oxygen gets further in behind the face.
• Location: if the silage face is in the sun, it warms up faster.
• Wind: once you are halfway through the pit, the walled pit can act like a wind tunnel. This lets more air into the feed.
• The silage face: an even, smooth face lets in less air and water than a ragged one.
• Rubbish in the feed: with every section, check there is no wire or other waste in the silage. That is how you prevent hardware disease.

How do you work out your feed-out rate?

Your feed-out rate depends on how much feed you use and how large the silage face is. The face is the width of the pit times the height of the silage.

1. Work out how much feed you take out of this pit per week, in cubic metres (m³).
2. Work out the area of the face: width x height of the silage, in m².
3. Divide the first figure by the second. The result is the number of metres per week.

An example: you take 30 m³ a week out of a pit that is 8 metres wide with silage 2.5 metres high. The face is 8 x 2.5 = 20 m². Your feed-out rate is then 30 ÷ 20 = 1.5 metres per week. Enough for winter, too little for summer.

Do you only know how many kilos you feed per day? Then you also need to know how much a cubic metre of your silage weighs. That differs per pit and per crop. As a guide, we work with fresh weight, so the feed as you take it out of the pit: 600 kg per m³ for grass and 740 kg per m³ for maize. So use your daily feed in kilos of fresh weight too, not dry matter. In our brochure we use 230 kg per m³, but that is dry matter. You can't mix those two figures.

What if your pit is too high or too wide?

The larger the silage face, the slower you move through the pit with the same amount of feed. A high or wide pit with a small herd will then not reach 1.5 or 2 metres a week. This is what you can do:

• Fill the pit lower or narrower. Match the height and width of the silage to how much you feed per week. You decide this at ensiling.
• Take it into account when building or adapting a silage pit. Work out in advance which width suits your herd.
• Have more than one pit? In summer, feed from the pit with the smallest face. That makes it easier to reach 2 metres a week. A pit with a large face suits the winter better, when 1.5 metres is enough.
• Pay extra attention to the other points. Good compaction, a tight face and an airtight cover on the rest of the pit make a low feed-out rate less risky.

Would you like to look at your own pit and feed-out rate together with us? Get in touch.