Animal welfare in a circular food system

Current intensive livestock farming is criticised for its high dependency on external inputs (e.g. concentrates) and association with sustainability issues, such as environmental pollution and animal welfare. A circular food system is envisaged as an alternative for the future. It entails that land is primarily used to produce plant biomass for human consumption and foodleftovers not suitable for human consumption are used as animal feed. Feeding food-leftovers to livestock contributes to a reduction of natural resource use such as land, water and fossil phosphorus, and to closing of nutrient cycles. The consequences of feeding food-leftovers for animal welfare, however, are unclear. We evaluated potential consequences for animal welfare of feeding food-leftovers to livestock by a literature review. Identified aspects related to provision of feed in livestock important for animal welfare include: (anti-)nutritional value, ingredient composition, physical form and structure, sensory characteristics, access to feed and timing of feed, dietary variation, and biological, physical and chemical hazards. The relation between those aspects and animal welfare is many-sided and complex in the way that various aspects of feed concurrently affect various aspects of animal welfare (i.e. physiologically, behaviourally and mentally). Food-leftovers can arise throughout the food production chain: in primary production, processing and packaging, retail and distribution and household consumption. They vary in characteristics, such as products from plant or animal origin, nutritional value, water and fibre content, and contamination risks. Animal welfare consequences of feeding foodleftovers were found to be largely similar to current feeding practices, but several knowledge gaps and challenges still need to be tackled. The envisaged transition to a circular food systems is a unique opportunity to simultaneously improve animal welfare substantially. This requires robust animals that can digest feed based on food-leftovers, skilled farmers and farming systems designed in line with the animals’ species-specific needs.