The potential of willow (Salix sp), a tannin-rich tree to reduce the environmental impact from ruminants and improve productivity

Willow leaves, abundant across Europe, offers high protein and moderate energy levels, making it a useful feed source. The research aimed to evaluate the inclusion of willow leaves to potentially mitigate environmental impacts and enhance productivity in ruminant systems.</p><p>Key objectives included determining effective inclusion levels for reducing methane and ammonia, assessing palatability, evaluating digestion and nutrient efficiency, and testing willow’s viability in silvopastoral systems.</p><p>In vitro studies showed that 100% willow inclusion reduced methane and ammonia by 64% without affecting digestibility.

In vivo trials with ewe hoggets' revealed no methane reduction at 20% inclusion, though fermentation patterns and microbial populations shifted. Beagle willow, with higher tannin content, reduced nitrogen digestibility but redirected nitrogen excretion from urine to faeces, potentially lowering ammonia emissions.</p><p>A grazing trial with beef steers showed a 27% methane reduction on a willow diet compared to grass, with no adverse effects on intake or energy use.