Sustainability of Dutch dairy farming systems: a modelling approach

The transition towards more sustainable dairy farming systems is a central element on the Dutch agenda for the reconstruction of the livestock production sector. The concept of sustainability needs to be quantified to evaluate the effectiveness of a transition towards more sustainable farming systems and to quantify the sustainability of farming systems. Furthermore, the transition process can be supported with improved insight into the effects of management measures and farming systems on individual sustainability aspects and overall sustainability. The general objective of the research presented in this thesis was to quantify sustainability at farm level and to gain insight into the effects of management measures and farming systems on all aspects of sustainability in dairy farming using farm-level modelling. Stakeholders, i.e. primary producers, consumers, industrial producers, and policy makers, were consulted to quantify subjective elements of sustainability and experts were consulted to quantify objective elements of sustainability. Consultation of stakeholders and experts showed that economic and internal social sustainability can be approximated by one attribute. External social and ecological sustainability need multiple attributes to be described adequately. Indicators were used to measure the performance of attributes and were included in a dairy farm Linear Programming (LP)-model to determine how farm management measures and farming systems affect different sustainability aspects. Multi-Attribute Utility Theory (MAUT) was used to develop an overall sustainability function for Dutch dairy farming systems in which all attributes and aspects were weighted hierarchically by consulting stakeholders and experts. Especially consumers and primary producers attach considerably different weights to sustainability aspects. This limits the possibility for developing one overall sustainability function that satisfactorily includes preferences of all stakeholder groups. The overall sustainability function per stakeholder group was applied to four experimental dairy farms. Finally, the overall sustainability function per stakeholder group was included as objective function in the dairy farm LP-model resulting in a Weighted Linear Goal Programming (WLGP)-model. Analysis with the WLGP-model showed that conventional dairy farms have the potential to achieve similar sustainability scores in comparison with organic dairy farms (and vice versa).