Early pre-silage season preparation pays dividends

Lallemand Animal Nutrition’s forage technical support, Lientjie Colahan, answers common questions about how to get ready for a successful silage season in 2026.

Q. Why hold an early-season review?

A. I’d recommend having a meeting early in the year with the contractor – or the farm team if silage is made in-house – alongside your nutritionist and farm consultant.

This needs to be an open, honest chat so that you can talk about what worked well last year and what didn’t.

If there were issues, such as clamp slippage or problems with sheeting, discuss why they may have happened and what changes are needed for this year.

For example, if density was an issue, consider adding another tractor for packing or using a compaction machine on the clamp. If soil contamination was a problem, assess whether it came from molehills or the cutting height and discuss ways to prevent it from happening again.

Even the best-laid plans may need to adapt depending on the weather and the type of spring, but an early meeting offers a valuable opportunity to address past challenges and improve this year’s silage-making process.

Lientjie Colahan, forage technical support at Lallemand (Image: web)

Q. What is needed for the silage pit ahead of cutting?

A. In advance of cutting, ensure the clamp is clean – ideally, pressure wash if possible.

While a clamp will never be sterile, removing old, composted material will help lower the yeast and fungal load, improving the efficiency of the silage-making process.

Check for and complete any necessary repairs. If a panel is damaged or new side sheets are needed, get them sorted to ensure the clamp is ready to fill when cutting starts.

Clear out effluent channels to ensure they meet the required standards and regulations.

Order sheeting and oxygen barrier film. Don’t just repeat last year’s order – think about whether there is enough sheeting for the recommended 1-1.5m overlay at the top and sides, or if more is needed.

Q. Why should you carry out pre-cut grass testing?

A. Pre-cut grass testing gives an indication of the quality of the grass you’re going into, and what the risk factors are for that crop.

It can be used to make sure the grass has used up the nitrogen applied, and to make sure the sugar levels are high enough to guarantee a good fermentation.

Test the grass two weeks before expected first cutting date, and again three to four days before cutting. For further cuts, test a few days before expected cutting date.

When getting a sample, walk in a ‘zig-zag’ or ‘w’ pattern across the field, cutting the grass at the height the mower will be cutting it for silage, and make sure there’s no contamination.

Optimal chop length depends on the type of grass (Image: web)

Q. Why consider using an inoculant?

A. Using a silage inoculant helps make sure the right bacteria dominate the fermentation process – namely lactic acid bacteria (LAB).

The faster the fermentation happens, the better it preserves dry matter, palatability, and nutrients until feed out.

Relying solely on naturally occurring LAB in the crop can be risky, as fermentation will be slower and less efficient, increasing the risk of moulds and spoilage yeasts.

Investing in a crop and condition-specific inoculant, such as Lallemand’s Magniva range, helps maintain feed value and maximises the return from forage stocks.

Q. What should you consider when choosing an inoculant?

A. With various inoculant options available, consider which is best suited for the challenges faced ensiling and at feed out.

A very wet silage will present very different challenges to a dry one, so choosing a crop and condition-specific inoculant will make sure the bacteria combination is the right match.

Using an inoculant that contains both homofermentative and heterofermentative bacteria, and enzymes helps to lock in silage nutrients and maintain them during feed out.

Using an inoculant that only contains homofermentative bacteria misses out on the antifungal compounds produced by the heterofermentative bacteria, which help combat spoilage when the clamp is opened.

Consider an inoculant that has added enzymes which help break down fibre, improving silage digestibility, and promote the activity of ‘good’ microbes for faster, more efficient fermentation and a lower spoilage risk.

Using a silage inoculant helps make sure the right bacteria dominate the fermentation process (Image: web)

Q. What to consider at cutting and clamp-filling?

A. Don’t cut the grass too low because there will be slower regrowth and there isn’t much feed value in the very bottom of the plant. It also helps avoid soil contamination, which can cause spoilage in the clamp.

Aim for a cut height of 6-8cm; if the fields look white after you’ve mowed them then you know you’ve gone too low. Leave a green tinge, so plants start growing again quicker.

The optimal chop length depends on the type of grass – wet grass needs a longer chop length, but dry grass needs a shorter chop of below 2cm. This will make it easier to roll and compact.

For multiple cuts in the same clamp, make sure the grass is spread out across the whole clamp in layers like a lasagne. This means the cows will get a good mix of everything that’s there when feeding from the top to the bottom of the clamp in a day.

When compacting, roll the crop all the time. As a rough rule of thumb the machines compacting need to weigh 25% of the weight of the forage coming in per hour – so 25 tonnes if you’re harvesting 100 tonnes of grass an hour.

Q. Why should you use an oxygen barrier film?

A. Using a good quality oxygen barrier silage film rather than a more conventional cling film or polyethylene film will drastically reduce the likelihood of oxygen getting to the silage to fuel the spoilage process.

A true oxygen barrier film will only let in a small amount of oxygen, which is measured as the volume of air that passes through a set area of plastic.

For example, a high oxygen barrier film, such as Lallemand’s OxyBlock, lets in less than 1cm3/m2/24 hours, while a conventional black and white polyethylene film lets in more than 300cm3/m2/24 hours. This increases to more than 1000 cm3/m2/24 hours for a conventional cling film wrap.