Processed hardwood sawdust may help stretch cattle and sheep rations during a severe forage shortage, but researchers caution that it should be regarded as complementary roughage rather than a replacement for silage, hay, or straw.
Scientists at the Norwegian University of Life Sciences tested birch sawdust in laboratory fermentation work, rumen-cannulated cows, and sheep.
They also ran a small pilot involving six Norwegian Red dairy cows fed aspen sawdust.
Strictly, sawdust was studied as a roughage substitute, not a 'feed additive'.
Fresh, untreated birch had little feeding value.
Just 3% of its dry matter had degraded after 96 hours in the rumen, while nearly 90% remained undegraded after 288 hours.
Steam explosion, using heat and pressure to open the wood-fibre structure, changed the picture.
Steam-exploded birch achieved organic matter digestibility of about 50% in sheep, compared with roughly 29% for untreated wheat straw and 78% for grass silage.
Its estimated net-energy value was around 4MJ/kg dry matter, against 1.9MJ for straw and 6.7MJ for silage.
In the six-cow pilot, untreated aspen eventually supplied about 27% of total dry-matter intake while some silage remained in the ration.
Cows adapted within seven to 12 days and no apparent health problems were recorded, although average milk yield slipped from 23.9kg to 21.9kg a day.
However, that trial was not standardised or statistically analysed.
It cannot establish the effect on production, health, or safety over a full feeding period.
The idea is relevant to Scotland, where dry seasons have already prompted warnings over lower forage stocks and costly straw however the main qualification is species.
Sitka spruce accounts for 43% of Scotland’s forestry area, whereas the Norwegian experiments centred on the hardwoods birch and aspen.
The paper says hardwoods are generally more digestible than softwoods, so its results cannot simply be transferred to typical Scottish spruce residues.
Nor is this a licence to use workshop sweepings.
Sawdust from preservative-treated wood is prohibited in animal feed, and any material would need a known source and treatment history.
Scottish livestock farms must also comply with feed hygiene, registration, and record-keeping rules.
The conclusion is cautious: clean, species-defined, and professionally processed sawdust could eventually act as an emergency ration extender, provided sufficient conventional long forage remains.
Ordinary raw sawdust is largely low-energy ballast and should not enter a ration without specialist nutritional and feed-safety advice.
The report was by Seid Ali Yimam, Egil Prestløkken, Lars Martin Hval and Alemayehu Kidane and published earlier in 2026.
Share