The SusTradeOff project aims to develop cutting edge technologies to study these trade-offs in two production systems (sheep and poultry): SusTradeOff aims to understand how different dietary protein sources are allocated by animals of different genetic backgrounds between production and immune function and how this allocation is affected by stage of production, disease or vaccination. To achieve these aims, biological materials and proteomics technologies will first be developed to study these trade-offs at the individual animal level, which will facilitate the identification of protein sources and/or targeted protein supplementation to enhance or maintain immune function in the face of high production demands. Population studies in experimental and commercial lines will investigate trade-offs between resilience, immunocompetence and production, providing additional genotypes and phenotypes to select in balanced breeding programmes. Data integration and modelling will provide prediction models for trade-offs and decision making tools that will then be validated at the production level with breeding industry partners under commercial conditions using industry standard operational scenarios. By developing integrated animal health and production management strategies to improve competitiveness and sustainability of animal production, especially by delivering more efficient use of proteins, the SusTradeOff project maps to the 3 Research Areas of the call SusAn.