Modelling short- and long-term resilience and efficiency of cattle production in Europe
Efficiency is a long-standing objective of dairy cattle production systems. However, the expected impact of external stressors such as climate change means resilience may now be an increasingly important production goal. Resilience characterises the ability of a system to moderate perturbations at any level, including the animal level, for example, where individual cows may be adapted to reduce heat-stress impacts on their production and functioning. Yet, there is uncertainty about the degree to which these goals are antagonistic, so this thesis aims to evaluate how objectives of resilience trade-off against efficiency objectives in the context of future agricultural production challenges, and to advance understanding of the value of resilience to dairy cattle production systems in Europe. These aims are achieved through inter-disciplinary approaches, and three important contributions to the literature are made. The first contribution, Chapter 2, is a state-of-play assessment of the application of stated preference approaches to understand stakeholder values in the field of agricultural breeding. This research draws on an innovative ranking tool to quantify how genetic traits are valued differently in reviewed studies depending on the system being evaluated. The review provides a knowledgebase of existing applications and highlights knowledge-gaps and key considerations for future applications, such as the accurate representation of heterogeneous values and motivations of the respondents. This systematic review lays the foundation for Chapter 3, where a novel application of a stated preference approach was used to ask stakeholders in European dairy systems how the value of genetic improvements to dairy cattle depend on whether the production goal is resilience or efficiency. Here, substantial differences in the value of some production, functional and novel traits between scenarios (resilience or efficiency goal) are presented. In addition to this, associations between socio-demographic characteristics of respondents and the relative values of genetic traits are discussed. Next, in Chapter 4, a stochastic, dynamic, multi-trait, individual-based model was developed that simulates a herd of individuals from conception to leaving the herd (due to sale, death or culling). With this daily time-step model, we mimic the biological performance and management of a specialist Scottish dairy herd under genetic selection and in several scenarios of future climate. Individuals are influenced by genetic and environmental variation, and performance data is used to calculate financial and environmental consequences. Results are presented in Chapter 5, which describes climate change impacts on dairy production, even for temperate regions such as southwest Scotland. Importantly, evidence is presented to demonstrate that failure to account for weather effects in similar – increasingly popular – models will cause the misrepresentation of performance metrics due to both short-term extremes and long-term incremental change.