Towards sustainable livestock systems: Developing and applying methods for broad sustainability assessment of pig and cattle systems

Meat and milk are valuable foods from livestock that contribute to quality of life for humans but have negative environmental, social and economic impacts. Measuring such impacts in sustainability assessments requires methods with a broad and deep focus. The overall aim of this thesis was to further develop sustainability assessment methods to broadly evaluate livestock systems and to use these methods to increase knowledge on how future sustainable pig and cattle production systems can be developed. Social life cycle assessment (S-LCA), Life cycle sustainability assessment (LCSA) and the One Health framework were developed further and used to assess the impacts of the different livestock systems i.e. organic and conventional Swedish pig production, future pig production scenarios and three cattle systems (cropland based dairy, grassland based dairy and grassland based suckler beef production) in southern Europe. S-LCA, LCSA and the One Health framework sustainability methods can assess important sustainability aspects for pig and cattle production systems and identify important trade-offs. Organic pig production had lower social risk for negative social impacts for pigs and consumers than conventional pig production but higher environmental impacts per kg for eutrophication, acidification and fossil depletion. Grassland based suckler beef production was more resilient to economic losses due to changes in interest rates, input prices and output prices, produced more protein (in meat) than found in the feed and had higher profitability compared to the other cattle systems. However, grassland based beef production had higher eutrophication, acidification and fossil depletion compared to the dairy systems. Changing the breeding goal of pigs, changing the diet composition by including silage and having other protein sources than soybean, and using renewable energy sources in future pig production can further reduce negative impacts