Animals convert unconsumed human biomass into valuable products (e.g. milk, meat, eggs, manure), thereby helping to transform our current food system into a circular one.
Animals as converters of non-consumed biomass
By converting biomass that humans cannot or do not want to eat into animal-source food and manure, farm animals recycle nutrients that otherwise would have been lost in a food system. Initial estimates indicate that up to one third (9-23 g) of the daily protein need (~50-60 g) of an average global citizen can be met through the intake of animal-sourced food produced by farm animals fed solely on residual streams, i.e. without using arable land for animal feed production.
The potential of animals in a circular food system
How much animal-source food can be derived from (aquatic and terrestrial) farm animals fed solely with residual streams, depends on their capacity and efficiency to use biomass. Ruminants, for example, have the capacity to use grassland biomass, in contrast to pigs, poultry and farmed fish. And, while some (breeds of) animals are highly productive when fed high quality feed, they might be unable to cope with residual streams. Using the CiFoS model, we aim to assess the potential of farms animals to increase the efficiency of our food system, while minimizing the systems’ impact on planetary boundaries. In order to do so, we need to investigate the availability of residual streams in a given food system, and which animals should receive these to make the best use of it.