Willow silvopastoral systems: a strategy to reduce methane emissions and maintain cattle performance

Authors: THOMPSON, JOSH - Queens University - United Kingdom; STERGIADIS, SOKRATIS - University Of Reading; CARBALLO-CRISTOBAL, OMAR - Agri-Food And Biosciences Institute; Zeller, Wayne; YAN, TIANHAI - Agri-Food And Biosciences Institute; LIVELY, FRANCIS - Agri-Food And Biosciences Institute; GILLILAND, JOHN - Queens University - United Kingdom; PURUSOTTAM, RUDRA - Queens University - United Kingdom; HUWS, SHARON - Queens University - United Kingdom; THEODORIDOU, KATERINA - Queens University - United Kingdom

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/12/2025
Publication Date: 6/2/2025
Citation: Thompson, J., Stergiadis, S., Carballo-Cristobal, O., Zeller, W.E., Yan, T., Lively, F., Gilliland, J., Purusottam, R. ., Huws, S., Theodoridou, K. 2025. Willow silvopastoral systems: a strategy to reduce methane emissions and maintain cattle performance. Scientific Reports. https://doi.org/10.1038/s41598-025-02289-0.
DOI: https://doi.org/10.1038/s41598-025-02289-0

Interpretive Summary: Silvopastoralism uses trees and shrubs to feed ruminants integrated alongside pasture. Willow (Salix sp.) is a common tree used in agroforestry for biofuel production. Willow leaves and branches contain condensed tannins (CTs) which can reduce enteric methane emissions and improve animal performance. Their effects on ruminant nutrition vary widely depending on both their chemical structure and concentration. This research study aimed to evaluate, for the first time, the potential of grazing willow in a silvopastoral system. The specific objectives were: a) assess the inclusion and structural composition of CTs in willow, and b) quantify CTs' effect on methane emissions and animal performance. Twenty steers were used in a two different grazing options, one grazing on willow silvopastoral systems (WFG) and the other on a perennial ryegrass grazing (PRG) platform. The steers grazing on WFG exhibited no differences in forage and total dry matter intakes compared to those in the PRG platform. The overall inclusion of CTs in the WFG treatment was 5.65% on a dry matter basis. No differences between treatments were observed in metabolizable energy or nitrogen intake. A 27% reduction in methane production was observed for WFG relative to PRG. Daily liveweight gain of steers on WFG was 31% lower than PRG, resulting in no difference in methane intensity, the amount of methane emitted per kilogram of milk or beef produced, between WFG and PRG. Despite willow's well-recognized role in livestock production systems across several countries and its promising contributions toward net-zero carbon goals—whether integrated within silvopastoral systems or utilized as tree fodder—this study is the first to concurrently evaluate its impact on both animal performance and methane emissions within a grazing context. This research study underscores the potential to combine agroforestry and rotational grazing platforms to reduce above-ground carbon emissions and increase below-ground carbon sequestration. These results highlight for the first time willow’s potential as a sustainable solution for reducing greenhouse gas emissions within ruminant systems, marking a key step in advancing climate-smart agricultural practices.

Technical Abstract: Silvopastoralism uses trees and shrubs to feed ruminants integrated alongside pasture. Willow (Salix sp.) is a common tree used in agroforestry for biofuel production. Willow leaves and branches contain condensed tannins (CTs) which can reduce enteric methane emissions and improve animal performance. Their effects on ruminant nutrition vary widely depending on both their chemical structure and concentration. This research study aimed to evaluate, for the first time, the potential of grazing willow in a silvopastoral system. The specific objectives were: a) assess the inclusion and structural composition of CTs in willow, and b) quantify CTs' effect on methane emissions and animal performance. Twenty steers were used in a two-treatment (grazing swards) by two period Latin square design study. The steers grazing on willow silvopastoral systems (WFG) exhibited no differences in forage (P=0.100) and total dry matter intakes (P=0.0591) compared to those in the perennial ryegrass grazing (PRG) platform. The overall inclusion of CTs in the WFG treatment was 5.65% on a dry matter basis, translating to an average daily CT intake of 617 g/d. The compositional analysis of purified CTs from willow showed a mean degree of polymerisation of 10.6, and a ratio of procyanidin/prodelphinidin of 28.9/71.2 while the ratio of cis/trans was found to be 23.4/76.7. No differences between treatments were observed in metabolizable energy (P=0.0728) or nitrogen (P=0.844) intake. However, neutral detergent fibre intake was 28% lower (P<0.001) for WFG compared to PRG. A 27% reduction in methane production was observed for WFG relative to PRG (P<0.001; 173 vs 273 g/d). Daily liveweight gain of steers on WFG was 31% lower than PRG (P<0.01; 0.72 vs 1.04 kg/d), resulting in no difference in methane intensity between WFG and PRG (P=0.555; 296 vs 269 g/kg). Willow plays a vital role in livestock production systems worldwide. This study is the first one to provide evidence of the significant potential for advancing net-zero carbon initiatives. To optimize animal performance, it is essential to establish appropriate inclusion rates of CTs with promising structural composition. This would be the appropriate approach to support both enhancement of animal production efficiency and environmental sustainability.