Sustainability assessment of egg production as affected by genotype and rearing system

Commercial egg production relies almost exclusively on the use of selected hen hybrids, which show higher productive efficiency than local chicken breeds. Crossbreeding with more productive genotypes could be a valuable strategy to improve local breeds utilization. To determine the effects of this strategy, the Life Cycle Assessment (LCA) methodology was applied for evaluating the influence of the laying hen genotype (case study #1) and the rearing system (case study #2) on the environmental impacts associated with table egg production. In case study #1, five genotypes were evaluated, i.e., two Italian local breeds (Bionda Piemontese and Robusta Maculata), their crossbreeds with a dual-purpose genotype (Sasso) and a commercial hybrid (Lohmann brown). In case study #2, enriched cage and free-range systems were compared. The impacts were evaluated applying the CML-IA baseline and the ReCiPe 2016 midpoint (H) methods considering productive performance and farm energy consumption data. In both case studies, the analysis was conducted throughout the laying period, with the functional unit defined as 1 kg of eggs. As for the genotype, the commercial hybrid showed the lowest emission values and the purebreds the highest ones (+20/76% compared to the hybrid), while crossbreeds showed lower emissions than the corresponding local breed (-7/-25%) due to the performance improvements. In case study #2, minimal differences in terms of environmental impact were detected, although some parameters showed slightly different values according to the rearing system. In both case studies, the main sources of environmental impacts were feed (>35%) and manure (>10%).