title: Impacts of feeding less food-competing feedstuffs to livestock on global food system sustainability.
abstract: Increasing efficiency in livestock production and reducing the share of animal products in human consumption are two strategies to curb the adverse environmental impacts of the livestock sector. Here, we explore the room for sustainable livestock production by modelling the impacts and constraints of a third strategy in which livestock feed components that compete with direct human food crop production are reduced. Thus, in the outmost scenario, animals are fed only from grassland and by-products from food production. We show that this strategy could provide sufficient food (equal amounts of human-digestible energy and a similar protein/calorie ratio as in the reference scenario for 2050) and reduce environmental impacts compared with the reference scenario (in the most extreme case of zero human-edible concentrate feed: greenhouse gas emissions -18%; arable land occupation -26%, N-surplus -46%; P-surplus -40%; non-renewable energy use -36%, pesticide use intensity -22%, freshwater use -21%, soil erosion potential -12%). These results occur despite the fact that environmental efficiency of livestock production is reduced compared with the reference scenario, which is the consequence of the grassland-based feed for ruminants and the less optimal feeding rations based on by-products for non-ruminants. This apparent contradiction results from considerable reductions of animal products in human diets (protein intake per capita from livestock products reduced by 71%). We show that such a strategy focusing on feed components which do not compete with direct human food consumption offers a viable complement to strategies focusing on increased efficiency in production or reduced shares of animal products in consumption.
authors.affiliation: Research Institute of Organic Agriculture (FiBL), Ackerstrasse 113, 5070 Frick, Switzerland christian.schader@fibl.org.
authors.forename: Christian
authors.identifier: http://orcid.org/0000-0002-4910-4375
authors.initials: C
authors.lastname: Schader
authors.affiliation: Research Institute of Organic Agriculture (FiBL), Ackerstrasse 113, 5070 Frick, Switzerland Institute of Environmental Decisions, ETH Zürich, Universitätstrasse 22, 8092 Zürich, Switzerland.
authors.forename: Adrian
authors.identifier: http://orcid.org/0000-0001-7232-9399
authors.initials: A
authors.lastname: Muller
authors.affiliation: Food and Agriculture Organization of the United Nations (FAO), Viale Terme di Caracalla, 00150 Rome, Italy.
authors.forename: Nadia El-Hage
authors.identifier: http://orcid.org/0000-0001-6421-1462
authors.initials: Nel-H
authors.lastname: Scialabba
authors.affiliation: Research Institute of Organic Agriculture (FiBL), Ackerstrasse 113, 5070 Frick, Switzerland.
authors.forename: Judith
authors.initials: J
authors.lastname: Hecht
authors.affiliation: Research Institute of Organic Agriculture (FiBL), Ackerstrasse 113, 5070 Frick, Switzerland.
authors.forename: Anne
authors.initials: A
authors.lastname: Isensee
authors.affiliation: Institute of Social Ecology Vienna (SEC), Alpen-Adria University Klagenfurt-Vienna-Graz, Schottenfeldgasse 29, 1070 Vienna, Austria.
authors.forename: Karl-Heinz
authors.identifier: http://orcid.org/0000-0002-8335-4159
authors.initials: KH
authors.lastname: Erb
authors.affiliation: Scottish Food Security Alliance-Crops and Institute of Biological and Environmental Sciences, University of Aberdeen, 23 St Machar Drive, Aberdeen AB24 3UU, UK.
authors.forename: Pete
authors.initials: P
authors.lastname: Smith
authors.affiliation: Food and Agriculture Organization of the United Nations (FAO), Viale Terme di Caracalla, 00150 Rome, Italy.
authors.forename: Harinder P S
authors.initials: HP
authors.lastname: Makkar
authors.affiliation: Research Institute of Organic Agriculture (FiBL), Ackerstrasse 113, 5070 Frick, Switzerland Bovicare GmbH, Hermannswerder Haus 14, 14473 Potsdam, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Klocke
authors.affiliation: Research Institute of Organic Agriculture (FiBL), Ackerstrasse 113, 5070 Frick, Switzerland.
authors.forename: Florian
authors.initials: F
authors.lastname: Leiber
authors.affiliation: Institute of Environmental Decisions, ETH Zürich, Universitätstrasse 22, 8092 Zürich, Switzerland.
authors.forename: Patrizia
authors.identifier: http://orcid.org/0000-0002-3784-1124
authors.initials: P
authors.lastname: Schwegler
authors.affiliation: Research Institute of Organic Agriculture (FiBL), Ackerstrasse 113, 5070 Frick, Switzerland.
authors.forename: Matthias
authors.initials: M
authors.lastname: Stolze
authors.affiliation: Research Institute of Organic Agriculture (FiBL), Ackerstrasse 113, 5070 Frick, Switzerland.
authors.forename: Urs
authors.initials: U
authors.lastname: Niggli
mesh_terms: D000821:Animal Feed; D000822:Animal Husbandry; D000818:Animals; D006801:Humans; D058751:Livestock; D008954:Models, Biological
keywords: consistency; food security; food system; livestock; sufficiency; sustainable intensification