High dry matter maize silage - harvest do’s and don’ts

For those farmers looking out over the vast brown savannahs that used to be green and pleasant, this years maize crop is a beacon of hope. Hope that the livestock won’t be staring into empty troughs this winter as the maize fills in some of the shortage of grass forage.

2022 has been a very strange year - for farmers in particular. Much of the UK has been affected by a severe drought whilst most of these isles have enjoyed warmer temperatures and higher sunlight levels than a “ normal” summer. This has produced a different maize crop than many of us might have been anticipating. In the drier areas the crop has suffered from the drought stress reducing yields, whilst in the North Western areas crops are looking better than ever. In every case, the expected dry matters are higher than we might be used to.

To make the most of what is available, you need to plan the harvest very carefully. So what are the potential pitfalls for this years maize harvest? In summary it’s a list of do’s and don’ts, and in particular a list of don’ts!

Don’t             

-       Cut too early

-       Chop too long

-       Skimp on compaction

-       Overlook the power of a good inoculant

The cost of cutting too early

The temptation to cut early is a strong one. You’re possibly staring at the gap in the forage stocks where that grass should be, and are thinking that the maize should be filling that space. Whilst the crop is lush and green the temptation is to take the maximum volume. If you wait the leaves begin to die, the stem hardens off and the volume reduces and there is less silage material to fill the hungry tummies. So why shouldn’t you cut the crop early?

Krone Big X cutting high dry matter maize silage

Well mostly it’s down to preserving nutrient levels. As the crop matures (or dies off) the nutrients in the leaves and stem are transferred to the cob; so they are not lost. Cut too early and you increase the risk of effluent run off. This is a pollution risk but more importantly effluent is full of feed value, leaching out of your silage and lost to the livestock. To maximise the feed value and fill the bellies, you would be better to cut later and incorporate some straw into the ration to fill the space. As an aside, the hot dry conditions have made straw a “cheap” fill belly this year, well at the moment anyway, so maybe secure a straw supply whilst prices are affordable. 

Choosing a chop length

Chop length in a high dry matter silage is super important. The higher the dry matter the shorter you need to chop it and the more value it will be to your cattle. It’s tempting to choose a longer chop length – to give the cattle something to chew on, but not in a higher dry matter crop. The problem with high dry matter silage is in the clamp and it’s one you may never see. Higher dry matters are more difficult to compact and consolidate, and this makes the silage face more permeable to oxygen. High dry matter maize silage is at high risk of aerobic losses.

Aerobic losses in the silage face can be a much as 40% of the total feed value, losses that you won’t see and losses that you can ill afford in a year of forage shortage. Choosing the correct chop length together with good compaction and consolidation will reduce the aerobic permeability of the silage & reduce losses. In addition to these measure you should also consider using a good silage inoculant.

How can an inoculant help in high dry matter maize silage?

Many farmers are aware that a good silage inoculant can help you make better silage, but what exactly is it doing and how can it help in high dry matter maize silage?

Firstly it’s important to exclude the perception that inoculants are only used when you’re making silage in poor conditions. Inoculants can only preserve the feed value in the crop, making the most of what you have. That’s exactly what we need to do when making a high-risk maize silage in a year of forage shortages. It’s vital to choose an inoculant that can rapidly turn sugars into lactic acid, reducing the crop pH, creating conditions where other undesirable micro-organisms can no longer prosper.

And that’s the key to preserving the silage – this speed of fermentation. The longer it takes to “make” silage, the more of these aerobic microbes will be establishing populations. These populations will be rendered inactive as the pH drops but they will spark back into life as soon as the silage is uncovered and oxygen is reintroduced.

So in order to redress the balance, we’ve had the Don’ts, so lets summarise the Do’s

 Do

-       Do harvest when the crop is properly mature with dry matters in the 28%-35% range

-       Do choose an appropriate chop length, between 20mm for 28% DM and 10mm for 35% DM

-       Do consolidate and compact carefully, and use a compactor if available

-       Do use a suitable silage inoculate to preserve the feed value of maize

-       Do consider adding straw into the ration of feed stocks are short and secure your supply before prices rise

 If you want to discuss how to make better maize silage or want to discuss any of the other aspects of silage making covered in this series – contact Jeremy Nash at Jeremy@silageconsultant.co.uk

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