Browsing by Author "Kyriazakis, Ilias"
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Item Open Access Comparing the environmental impacts of alternative protein crops in poultry diets: The consequences of uncertainty(Elsevier Science B.V., Amsterdam., 2013-10-31T00:00:00Z) Leinonen, Ilkka; Williams, Adrian G.; Waller, Anthony H.; Kyriazakis, IliasThe statistical significance of the effects of including different protein sources in poultry diets on the environmental impacts Global Warming Potential (GWP), Eutrophication Potential (EP) and Acidification Potential (AP) of typical UK broiler meat and egg production systems was quantified using the Life Cycle Assessment (LCA) method combined with an uncertainty analysis. The broiler and layer diets compared in the study were either standard soya-based, or alternative diets based on European-grown protein crops, including field beans, field peas, sunflower meal and whole rapeseed. Different methods for accounting for land use change (LUC) in feed crop production were applied, including (1) a weighted average of "new" and "mature" agricultural land used for soya production ("best estimate" scenario), (2) assuming no LUC in the production of soya used in these diets ("sustainable soya" scenario) and (3) including indirect LUC for all arable crop production ("top-down" scenario). Monte Carlo simulations were used to quantify uncertainties in predicted impacts and to perform statistical comparisons between the effects of different diet compositions. The results showed that when included at relatively high levels in the diets (10-30% by mass), peas, beans and rapeseed could slightly reduce the simulated mean value of GWP (up to 12%) of broiler meat and egg production. However, when uncertainties in the data were taken into account, these reductions were not statistically significant. Furthermore, the reduction in GWP strongly depended on the method of LUC accounting applied in the analysis. With the "sustainable soya" and "top-down" scenarios, only small, non-significant differences between the different diets were found. In the case of EP, only small non-significant changes could be achieved with the alternative protein sources. For AP, a significant reduction of more than 20% could be achieved if the crude protein content of the broiler diet was reduced by using peas in combination with pure amino acids. This study demonstrates the importance of a holistic approach, coupled with Monte Carlo uncertainty analysis, to evaluate the environmental impacts of livestock systems. It takes into account the environmental burdens related, for example, to feed production and transport and differences in emissions from housing and the end use of the manure. Furthermore, due to the systematic uncertainty analysis, the statistical significance of the effects of different feeding scenarios can now be evaluated.Item Open Access Hotspots and bottlenecks for the enhancement of the environmental sustainability of pig systems, with emphasis on European pig systems(Springer Nature, 2023-11-16) Pexas, Georgios; Kyriazakis, IliasAlthough pig systems start from a favourable baseline of environmental impact compared to other livestock systems, there is still scope to reduce their emissions and further mitigate associated impacts, especially in relation to nitrogen and phosphorous emissions. Key environmental impact hotspots of pig production systems are activities associated with feed production and manure management, as well as direct emissions (such as methane) from the animals and energy use. A major contributor to the environmental impacts associated with pig feed is the inclusion of soya in pig diets, especially since European pig systems rely heavily on soya imported from areas of the globe where crop production is associated with significant impacts of land use change, deforestation, carbon emissions, and loss of biodiversity. The “finishing” pig production stage contributes most to these environmental impacts, due to the amount of feed consumed, the efficiency with which feed is utilised, and the amount of manure produced during this stage. By definition therefore, any substantial improvements pig system environmental impact would arise from changes in feed production and manure management. In this paper, we consider potential solutions towards system environmental sustainability at these pig system components, as well as the bottlenecks that inhibit their effective implementation at the desired pace and magnitude. Examples include the quest for alternative protein sources to soya, the limits (perceived or real) to the genetic improvement of pigs, and the implementation of alternative manure management strategies, such as production of biogas through anaerobic digestion. The review identifies and discusses areas that future efforts can focus on, to further advance understanding around the potential sustainability benefits of modifications at various pig system components, and key sustainability trade-offs across the environment—economy—society pillars associated with synergistic and antagonistic effects when joint implementation of multiple solutions is considered. In this way, the review opens a discussion to facilitate the development of holistic decision support tools for pig farm management that account for interactions between the “feed * animal * manure” system components and trade-offs between sustainability priorities (e.g., environmental vs economic performance of pig system; welfare improvements vs environmental impacts).