Date: 18th September 2026
Risk of poor fermentation from late-season silage cuts
Malvern, United Kingdom – As many farmers look to take a late-season silage cut to bolster forage stocks, Lientjie Colahan, forage technical support at Lallemand Animal Nutrition, offers advice on how to maximise yields and avoid spoilage. “Many farmers missed a cut earlier in the year due to the very dry weather conditions, and will be looking to get a late cut in towards the end of September or up to mid-October. “With concerns over forage shortfalls this winter and potentially into next spring, farmers are trying to build up their forage stocks.”
However, when taking a late-season cut, farmers are more likely to face a challenging fermentation, she warns. “Harvesting the crop in cooler, wet conditions often seen in autumn will increase the risk of bringing soil into the clamp, and therefore spoilage microorganisms, as well as moisture, which dilutes the lactic acid that drives pH down. “This mix of factors predisposes silage to inefficient fermentation, with knock on impacts for rumen health and performance,” Mrs Colahan explains. Using an inoculant will be particularly important this year to mitigate these risks, she adds. “It’s important to choose an inoculant containing acidifying lactic acid bacteria to drive fermentation as this is the primary challenge, but antifungal lactic acid bacteria and enzymes are still key components to ensure a stable, highly digestible feed source. “An inoculant such as Magniva Platinum Grass Wet contains a high proportion of acidifying bacteria to drive fermentation, while also containing antifungal bacteria that help inhibit fungal growth and reduce feed-out spoilage. “This is important as the key challenge when silage has been harvested in wet conditions is the initial fermentation, with potentially more soil contamination present in the crop. “An inoculant specifically designed for these conditions ensures that fermentation happens as quickly and efficiently as possible, reducing the risk of spoilage and maximising the available crop in a year when forage shortfalls are likely across the UK,” she says. When taking a later cut of silage, she also recommends a mowing height of 10cm, especially in wet conditions as this leaves the most contaminated part of the plant in the field, minimising the spoilage microorganisms brought into the clamp. “While farmers will want to maximise dry matter from the field, cutting too low will increase dry matter losses by bringing more soil and spoilage bacteria into the clamp. This can negatively impact fermentation, meaning any dry matter gained by reducing mowing height will be lost due to dry matter losses from a poor fermentation.”
When making silage during wet conditions, it is also worth increasing the chop length slightly and trying to layer the clamp like a sandwich or lasagne, she adds.
“If silage is harvested in wet conditions, layering the crop as evenly as possible is important for consolidation and to reduce the risk of the clamp slipping when silage is being fed out.
“If space allows, late cut silage should also be put in a separate clamp or pile, as the nutritional quality will be very different and this will allow you to feed it selectively,” she concludes.
Source: industry press release.