title: Income Disparities and the Global Distribution of Intensively Farmed Chicken and Pigs.
abstract: The rapid transformation of the livestock sector in recent decades brought concerns on its impact on greenhouse gas emissions, disruptions to nitrogen and phosphorous cycles and on land use change, particularly deforestation for production of feed crops. Animal and human health are increasingly interlinked through emerging infectious diseases, zoonoses, and antimicrobial resistance. In many developing countries, the rapidity of change has also had social impacts with increased risk of marginalisation of smallholder farmers. However, both the impacts and benefits of livestock farming often differ between extensive (backyard farming mostly for home-consumption) and intensive, commercial production systems (larger herd or flock size, higher investments in inputs, a tendency towards market-orientation). A density of 10,000 chickens per km2 has different environmental, epidemiological and societal implications if these birds are raised by 1,000 individual households or in a single industrial unit. Here, we introduce a novel relationship that links the national proportion of extensively raised animals to the gross domestic product (GDP) per capita (in purchasing power parity). This relationship is modelled and used together with the global distribution of rural population to disaggregate existing 10 km resolution global maps of chicken and pig distributions into extensive and intensive systems. Our results highlight countries and regions where extensive and intensive chicken and pig production systems are most important. We discuss the sources of uncertainties, the modelling assumptions and ways in which this approach could be developed to forecast future trajectories of intensification.
authors.affiliation: Biological Control and Spatial Ecology, Université Libre de Bruxelles, Brussels, Belgium; Fonds National de la Recherche Scientifique, Brussels, Belgium.
authors.forename: Marius
authors.initials: M
authors.lastname: Gilbert
authors.affiliation: Animal Production and Health Division (AGA), Food and Agriculture Organization of the United Nations (FAO), Rome, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Conchedda
authors.affiliation: Department of Ecology and Evolutionary Biology, Princeton University, Guyot Hall, Princeton, New Jersey, United States of America.
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Van Boeckel
authors.affiliation: Animal Production and Health Division (AGA), Food and Agriculture Organization of the United Nations (FAO), Rome, Italy.
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Cinardi
authors.affiliation: Biological Control and Spatial Ecology, Université Libre de Bruxelles, Brussels, Belgium; Fonds National de la Recherche Scientifique, Brussels, Belgium.
authors.forename: Catherine
authors.initials: C
authors.lastname: Linard
authors.affiliation: Biological Control and Spatial Ecology, Université Libre de Bruxelles, Brussels, Belgium.
authors.forename: Gaëlle
authors.initials: G
authors.lastname: Nicolas
authors.affiliation: Biological Control and Spatial Ecology, Université Libre de Bruxelles, Brussels, Belgium; Department of Livestock Development, Bangkok, Thailand.
authors.forename: Weerapong
authors.initials: W
authors.lastname: Thanapongtharm
authors.affiliation: Animal Production and Health Division (AGA), Food and Agriculture Organization of the United Nations (FAO), Rome, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: D'Aietti
authors.affiliation: Environmental Research Group Oxford, Department of Zoology, Oxford, United Kingdom.
authors.forename: William
authors.initials: W
authors.lastname: Wint
authors.affiliation: Emergency Center for the Control of Transboundary Animal Diseases (ECTAD), Food and Agriculture Organization of the United Nations (FAO), Hanoi, Vietnam.
authors.forename: Scott H
authors.initials: SH
authors.lastname: Newman
authors.affiliation: Livestock Systems and Environment (LSE), International Livestock Research Institute (ILRI), Nairobi, Kenya.
authors.forename: Timothy P
authors.initials: TP
authors.lastname: Robinson
mesh_terms: D000822:Animal Husbandry / Q000191:economics* / Q000379:methods; D000818:Animals; D002645:Chickens; D003906:Developing Countries; D004777:Environment; D006801:Humans; D007182:Income; D018803:Models, Economic; D012922:Social Change; D034421:Sus scrofa