Different life cycle assessment methods and causes of variation in estimates of global warming in chicken and pork production systems: A critical systematic review

• Published in: Livestock science Vol. 276; p. 105320
• Main Authors: Silva, Jéssica Pereira, Giehl, Carlo Juliantro, Cardinal, Kátia Maria, Andretta, Ines, Ribeiro, Andréa Machado Leal
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-10-2023
• Subjects: Equivalent carbon dioxide; Greenhouse effect gases; Intensive productions; Equivalent carbon dioxide; Intensive productions; Greenhouse effect gases
• ISSN: 1871-1413; 1878-0490
• DOI: 10.1016/j.livsci.2023.105320

•Life cycle assessment allows identifying fundamental points that can be modified to improve environmental performance within broiler and pig production chains.•Feed production for pigs and chickens is considered the main contributor to the impact of GWP in LCA studies.•There is great variability of the results found in the literature, for this it is necessary a greater unification of the methodological choices.•The management of waste from production is another important point that is little explored in LCA studies.•In general, the most cited strategies to reduce the environmental impact are through the formulation of diets and feeding strategies.
Life cycle assessment (LCA) has been widely used in recent years in swine and chicken production systems. This methodology aims to analyze the environmental aspects and measure the environmental impact of a product throughout its life cycle. Thus, this review will evaluate the application of life cycle assessment (LCA) in the Chicken and swine production system. to identify differences in LCA and explore the causes of variations between current works, main methodological differences in studies of the life cycle of swine and chickens, and explore the different values found in the literature in relation to greenhouse gas emissions for the same functional unit (FU). In swine and chicken production, values from 1.40 to 5.78 kgCO2-eq and 1.05 to 9.35 kgCO2-eq, per kg live weight, are observed, respectively. This variability occurs as a result of, some authors perform the calculation for only one production phase (for example, only the finishing phase without considering the sows that generated the piglets to be slaughtered); others carry out an evaluation of only one productive phase (piglets from 7 to 35 days of age). There are studies considering the addition of several factors, such as animal feed, water, housing and transport. Choices such as defining boundaries (“from cradle to farm gate” or “from cradle to slaughter”), animal density, consideration of Land Use Change (LUC) and whether irrigation is used in grain production for animal feed often alter outcomes. The greatest impact of both production systems is associated with food - when LUC is added to the calculation, the impact is even more pronounced. The consideration of the LUC in soy production, especially in Brazil, is a recurring debate among the studies evaluated, about whether or not to include the deforestation factor; In conclusion, it is necessary to make the assessment as complete as possible, and the main objective of future studies should be to increase transparency regarding the criteria used in the LCAs.