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Research article - Peer-reviewed, 2023

Environmental consequences of pig production scenarios using biomass from rotational grass-clover leys as feed

Zira, Stanley; Salomon, Eva; Akerfeldt, Magdalena; Roos, Elin


Production of pork based on monoculture cereal-based cropping systems causes sub-stantial environmental pressures and feed-food competition. This study evaluated the environmental consequences of five different scenarios involving inclusion of rotational grass-clover leys and incorporation of grass-clover biomass in pig diets: (1) a conven-tional reference scenario without grass-clover biomass; (2) a conventional scenario with replacement of feed with grass-clover silage in a total mixed ration, i.e., with grass-clover biomass replacing other feed; (3) an organic scenario using grass-clover silage for enrichment purposes only; (4) an organic scenario using grass-clover silage for enrichment purposes and additional grass-clover leys for green manuring; and (5) an organic scenario using grass-clover silage and pasture to replace feed. The functional unit was 1 kg of pork slaughter weight and the system boundary was from cradle to farm gate. We used life cycle assessment, the introductory carbon balance method and human edible feed conversion efficiency to assess the performance of the pig production system. Introducing grass-clover biomass as a total mixed ration in conventional pig diets, reduced the climate impact (-17%), eutrophication (-7.1%), marine eutrophication (-15%), energy use (-13%), and feed-food competition (-20%) per kg of pork meat, while acidification (+2.7%) and land use (+1.5%) were slightly increased compared with the reference. The lower climate impact (without considering soil carbon change) was attributable to reduced fertilizer and diesel needs due to pre-crop effects. Overall, feeding grass-clover biomass decreased several environmental impact categories, feed-food competition and improved cereal-based cropping systems by the introduction of grass-clover leys.(c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (


Conventional; Organic; Silage; Enrichment; Grain replacement; Pork

Published in

Environmental technology & innovation
2023, volume: 30, article number: 103068

Authors' information

Swedish University of Agricultural Sciences, Department of Animal Breeding and Genetics
Salomon, Eva
RISE Research Institutes of Sweden
Swedish University of Agricultural Sciences, Department of Animal Nutrition and Management
Swedish University of Agricultural Sciences, Department of Energy and Technology

UKÄ Subject classification

Environmental Sciences related to Agriculture and Land-use
Animal and Dairy Science

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