Sustainable goat production: modelling optimal performance in extensive systems

Abstract

Context Strategies for achieving greater ruminant livestock productivity are essential to meet the food demands of growing populations, but sustainable changes are difficult to identify given the inherent complexity of such systems. Systems models can address this issue by allowing the impact of potential changes to be explored. Aims To develop a holistic systems model for goat production in an extensive Mediterranean environment which could allow changes in key management factors influencing the system to be investigated. Methods Initially, a conceptual comprehensive stock-and-flow model of a representative Mediterranean goat production system was constructed. This was used to identify informative indicators that would represent the overall technical and economic performance of the system. Sub-models were then assembled to build the full systems model. The model was parameterised with data collected over 3 years for goat holdings in northern Morocco. Scenario analysis techniques are used to explore the strategies that optimise performance under climate and feed price challenges. Key results Meat production is particularly important during periods of drought when increased meat yields can counteract the expected reduction in milk yields, to protect human food security, prevent excessive rangeland degradation and preserve natural nutritional resources. Feed price shocks during drought can have significant negative impacts on the system and zero feed input is shown to be a more sustainable strategy than reliance on high price feed during drought. Any alternative feed sources need to have a high forage component to reduce grazing periods significantly and promote rangeland preservation. Implications A diverse management strategy with a mixed meat and dairy semi-intensive production is more stable than specialised dairy systems and allows goat production and financial viability of intensification to be maintained under climatic stress; maintaining meat production was necessary to optimise performance. Conclusions The model allows improved insight into management strategies which could optimise animal husbandry performance in goat subsistence systems. However, the work also demonstrates the difficulty of constructing a truly holistic model since, to be practical, such constructs must necessarily be bounded; parameter selection and the limits to the boundaries imposed are inevitably critical.