To monitor the trends in the environmental impact of the Dutch livestock farming industry a model was made which can be used to analyse the supply chain at various reference levels. Separate LCAs were drawn up for three stages in the supply chain. These can be combined at a later stage to construct a total LCA of the retail products. These stages in the supply chain are:
- Rearing of the young animal
- The production phase of the animal (meat, milk)
- The slaughter and cutting and boning phase (packed meat
Calculations of the environmental impact of by-products are based on substitution, such as replacing chemical fertiliser with manure and replacing energy carriers with products obtained from the processing of slaughter by-products. Figure 1 illustrates the results for pork.