Effect of Three Husbandry Systems on Environmental Impact of Organic Pigs

Gwendolyn Rudolph,Barbara Früh,Sandra Edwards,Matthias Meier,Davide Bochicchio,Werner Zollitsch,Jean Dourmad,Armelle Prunier,Christoph Winckler,Roland Brandhofer,Gillian Butler,Sabine Dippel,Stefan Hörtenhuber,Christine Leeb

doi:10.3390/su10103796

Abstract

This study examined the environmental impact of the three common organic pig husbandry systems, indoor (n = 24), partly outdoor (n = 30), and outdoor (n = 10), in eight European countries. Global warming (GWP), acidification (AP), and eutrophication potential (EP) was assessed per 1000 kg pig live weight on 64 farrow-to-finish pig production chains (cradle to farm gate). GWP, AP, and EP varied greatly, and the most important source was feed production, followed by housing. GWP did not differ between systems (p = 0.934), but AP in indoor systems and EP in outdoor systems were higher than in partly outdoor systems (p = 0.006 and p = 0.010, respectively). The higher AP in indoor systems can mainly be explained by NH3 arising from manure spreading, while PO4-eq arising from feed consumption and emissions on pasture accounted for the higher EP in outdoor systems. Associations of farm characteristics with (reduced) environmental impacts were mainly found for AP and EP, and included: (Increasing) farm size, numbers of piglets born and weaned per litter, (bought-in) mineral feed, and high-protein by-products, the latter probably connected to beneficial effects of appropriate dietary digestible lysine levels and feed conversion ratio. Increasing carcass weights and dietary cereal proportions were associated with higher environmental impacts. Overall, variation was mostly higher within than between systems, and measures to mitigate environmental impact were identified.

Highlights

Together with the general growth of organic farming in many European countries, organic pig farming has expanded in recent decades [1]
The analysis focuses on the environmental impact of three common organic pig husbandry systems, indoor (IN), partly outdoor (POUT), and outdoor (OUT), regarding their GWP, acidification potential (AP), and eutrophication potential (EP)
The ranking of the husbandry systems was not consistent regarding environmental impact; whereas the GWP was similar in all systems; POUT had less AP than IN, and less EP than OUT

Summary

Introduction

Together with the general growth of organic farming in many European countries, organic pig farming has expanded in recent decades [1]. Sustainability and its assessment, covering environmental, economic, and social aspects, have gained importance in recent years. The Sustainability Assessment of Food and Agriculture systems (SAFA) Guidelines [7] have been developed as an international reference document to allow for consistent analyses and assessments despite the complexity of sustainability. According to the SAFA guidelines, sustainability consists of four dimensions: Good governance, environmental integrity, economic resilience, and social well-being. In the dimension of environmental integrity, the following themes are addressed: Atmosphere, water, land, materials and energy, biodiversity, and animal welfare

Methods

Discussion

Conclusion