Livestock farmers facing issues such as silage heating, clamp slippage or mycotoxin contamination are being urged to re-evaluate their silage-making methods.
That’s the advice from Freya Webber, technical business manager for Volac in Scotland and Northern England, who says these three problems are consistently raised by farmers. Here, she outlines practical steps to address each one.
1. Silage heating
Often associated with maize or wholecrop cereal silage, heating is increasingly seen in grass silage too, Freya notes.
“Usually it is due to a combination of grass being ensiled too mature and too dry, which contributes to inadequate consolidation,” she explains.
“Allowing yeasts and moulds to grow in the clamp in the presence of air. It is also not helped if a silage additive is used that does not tackle yeasts and moulds.”
Once heating sets in, the energy value of the silage drops significantly.
Freya’s tips to prevent heating:
Harvest early, before the grass becomes too stemmy.
Monitor dry matter (DM) levels during wilting, aiming for 28–32% DM.
If over-wilted, chop the grass shorter to improve compaction.
Use an appropriate additive – preferably one that combats yeasts and moulds.
She recommends dual-action additives like Ecocool, which both enhance fermentation and control microbial activity. Trials show it can keep grass silage cool for over 15 days once exposed to air.
2. Clamp slippage
Clamp slippage – where the lower sections of the clamp collapse – is an increasing issue, Freya says, with several potential causes:
Grass that’s too wet, lush, or leafy
Incorrect chop length
Poor or uneven consolidation
Over-filled or wide clamps
“Lusher, younger grass will have more tender cells, which are more easily ruptured under pressure. So if the crop is lush and below 30%DM, it’s especially important not to over-fill them – for example, don’t fill them much more than 3m high,” she explains.
To reduce the risk of slippage:
Improve wilting using techniques like tedding to raise %DM.
Adjust chop length to better bind the silage – wetter grass typically needs a longer chop.
Avoid overfilling: Keep clamp height to around 3m for lush grass under 30% DM.
Divide wide clamps into narrower sections if possible.
Ensure even consolidation from top to bottom.
Freya adds a word of caution: “Care should always be taken around silage clamps, but especially if the silage is moving as the timing of a slip can’t be predicted.”
3. Mycotoxin contamination
Moulds growing in poorly managed silage can produce mycotoxins, which can lead to a wide range of health problems in livestock.
“Taking steps to minimise mould growth – such as fully removing air from the clamp with effective consolidation and avoiding slippage – will help to reduce the risk,” says Freya.
She notes that Ecocool has proven effective in maize silage at preventing both visible mould and the build-up of key mycotoxins after exposure to air.
If mycotoxins are suspected:
Consult a vet
Test the silage using services like Mycocheck, which screen for a variety of mycotoxins.
Where contamination is confirmed, consider applying a mycotoxin binder such as Ultrasorb to reduce risks in the final feed.
Whether it's heating, slippage, or hidden toxins, silage problems can have a significant impact on livestock performance and farm productivity. Revisiting basic silage principles and making informed adjustments can make all the difference.
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