CONTEXT: Many livestock diseases persist as endemic processes rather than as isolated outbreaks. These diseases affect herd dynamics, production, economic outcomes. In such settings, livestock systems evolve through interdependent interactions between population demography, disease transmission, and control interventions. However, most epidemiological-economic models are oriented toward episodic disease shocks and short-term containment, which limit their usefulness for policy analysis under persistent disease pressure. OBJECTIVE: This study develops and applies an epidemiological-economic modeling framework to assess the long-term impacts of endemic livestock diseases such as FMD on herd populations, production, and economic outcomes, as well as the cost-effectiveness of alternative disease control strategies. METHODS: A system dynamics-based herd dynamics model was linked with an endogenous compartmental disease transmission model to simulate two-way feedbacks between herd demography, endemic disease spread,and production outcomes over two decades. The framework captures births, natural and disease-induced mortality, productivity losses, and intervention effects under sustained disease pressure. Public-sector intervention costs were incorporated into a benefit-cost analysis to compare vaccination, quarantine, and combined vaccination-quarantine strategies. RESULTS AND CONCLUSIONS: Simulation results indicate that endemic disease can substantially affect herd growth, meat and milk production, and economic returns over time. In the absence of control, herd size is 24% lower by the end of the simulation period, while meat and milk production decline by approximately 20% and 18%, respectively, relative to the most effective control strategy (combined vaccination-quarantine). Although combined vaccination and quarantine reduce infections by more than 65% and generate the largest gains in population and production, lower-cost interventions such as quarantine alone produce higher benefit-cost ratios (46.34). The results show clear trade-offs between epidemiological effectiveness and economic efficiency that emerge in long-run, system-level analyses. SIGNIFICANCE: By modeling endemic disease dynamics alongside herd demography and economic outcomes, this study provides an epidemiological-economic analysis of livestock systems beyond outbreak-focused approaches. The framework is adaptable to other endemic livestock diseases, production systems, and country contexts where persistent disease pressure constrains productivity and where policy decisions require balancing long-term health outcomes with limited resources.

Livestock diseases such as Rift Valley Fever (RVF) present systemic threats to animal health, rural livelihoods, and national economies in endemic regions. However, conventional impact assessments often fail to capture the nonlinear feedbacks, time lags, and cross-sectoral interactions involved. This study develops a dynamic, multi-component system dynamics (SD) model to simulate the Epidemiological and Economic impacts of RVF outbreaks in Ijara County, Kenya, under alternative vaccination strategies. The model integrates biologically detailed Susceptible Exposed Infectious (SEI) dynamics for Aedes and Culex mosquito vectors, Susceptible Exposed Infectious Recovered (SEIR) livestock infection dynamics, herd demography, and end-market processes, incorporating demand-side shocks and behavioral feedback. Using a 10-year simulation with a daily time-step, parameterized with primary and secondary data, including El Niño associated rainfall patterns and producer survey results, the model reproduces key outbreak features consistent with historical RVF events and enables ex-ante comparison of policy responses. Findings indicate that the business-as-usual (BAU) strategy, involving delayed reactionary vaccination, yields only marginal improvements in herd recovery and producer income relative to no intervention. In contrast, annual preventive vaccination with sufficient coverage of susceptible animals prevents simulated outbreaks within the model horizon, while biannual and triennial strategies reduce outbreak severity but do not fully eliminate risk. Shortening the delay between outbreak onset and vaccination initiation substantially reduces livestock losses and improves income recovery trajectories. These results highlight the value of system dynamics modeling for evaluating intervention strategies under uncertainty. The model offers a decision-support tool for livestock health policy, demonstrating that proactive vaccination and rapid response outperform delayed, reactive approaches in both disease control and economic resilience in RVF-prone pastoral systems.

Significant progress has been made in cereal production in Bangladesh due to an agricultural policy environment that prioritizes the productivity of staple crops over fruit and vegetables (F&V). However, many smallholder farmers remain poorly connected to markets, which may lead to a limited supply response of F&V that can reduce opportunities for sufficient intake in neglected, consumer-facing, smaller retail markets. To address this issue, aggregation schemes have been conceived that collect and transport F&Vs on behalf of multiple farmers. Given the volume of horticultural produce produced and the reliance on developed transport infrastructure, aggregation schemes tend to supply wholesale and urban markets rather than underdeveloped rural and isolated markets. To this end, we investigated how a particular aggregation intervention ('Loop') could potentially improve the distribution of F&V to smaller markets whilst improving farmer benefits. We used an innovative system dynamics modeling approach based on Loop`s aggregation services in Jashore, Bangladesh, and to identify the potential trade-offs between consumer outcomes in retail markets and farmer benefits. We find that combining aggregation with a quota at the smaller market, transport subsidy, and current price growth does not result in trade-offs between consumer purchases and farmers`benefits. However, combining aggregation with current price growth can increase demand without losing farmers`benefits. The findings emphasize that standalone and multiple market-oriented interventions generate broader win-win benefits to promote inclusive food systems.

CONTEXT: Peste des petits ruminants (PPR) remains a persistent challenge for small ruminant production in Senegal, leading to economic losses for livestock keepers. Gender dynamics and socio-cultural factors influence production decisions at the household level. Despite its relevance, economic impact models of PPR have not incorporated gender dynamics. OBJECTIVE: This paper seeks to redress this gap by disaggregating the farm-level impacts of PPR based on the gender of the household head and implementers of routine and management activities in small ruminant production at the household level. METHODS: To quantify the gendered economic impacts of PPR, a system dynamics model was developed with four modules: integrated production -epidemiology, economics and profitability, disease control, and marketing. The model was parameterised based on survey data from 747 households in 49 agro-pastoral and pastoral villages in Senegal and augmented by secondary data. The model was validated (structurally and behaviourally) and simulated for 30 years with a weekly timestep. A set of disease scenarios were run for ten different farm household typologies based on the gender of the household head and household members who perform production management activities (like purchasing, selling, gifting, and vaccinating animals) and routine activities (like feeding, cleaning pens, and caring for sick animals). RESULTS AND CONCLUSIONS: Model results estimated annual reductions in farm profitability of 51% to 61% with a hypothetical 25% incidence rate of PPR, corresponding to an average of $1051 to $1246 USD lost per household per year. In the two most impacted household typologies, management activities were performed by either men only or women only, and in the three least impacted household typologies, management activities were shared by men and women. The least impacted household typology with the highest gross margins without PPR ($2429 USD per year) and the lowest percentage of loss (51%) was female -headed households with men and women doing management tasks and primarily women or girls doing routine activities. SIGNIFICANCES: Households with both women and men engaged in management activities were less impacted by PPR, highlighting the crucial role of women ' s agency in management decisions taken in small ruminant production at the farm level. The findings further provide the empirical grounding for considering gender dynamics in interventions to control PPR and other livestock diseases in small ruminant production systems.

A complex set of factors affect the production and sale of livestock in Somaliland, including feed supply, diseases, and demand, among others. This study constructs a system dynamics (SD) model to simulate the impacts of baseline dynamics and alternative value chain interventions to address inherent constraints. Findings indicate that Somaliland incurs high economic losses due to occasional animal export bans associated with Rift valley fever (RVF) outbreaks (up to 12% of GDP) and lack of pasture during droughts, given the lack of effort by producers to balance their flock sizes with stocking capacity. Under the baseline conditions, prospects for growth of the small ruminants' sector are poor as the stocking rate is centered and stagnated at about 2.54 million TLUs, and a decline is projected in the long run. In contrast, the adoption of optimization of animal herd sizes in order to balance feed demand with supply could (ceteris-paribus) enhance productivity, boosting exports and domestic supply of slaughter animals and also lead to improved rangeland conditions, ultimately reversing the projected long-run erosion of stocking capacity.

Standard tools that can quantitatively track the impacts of higher global demand for animal-sourced food to their local environmental effects in developing countries are largely missing. This paper presents a novel integrated assessment framework that links a model of the global agricultural and food system, a landscape-level environmental impact assessment model, and an ecosystem services simulation model. For Tanzania, this integrated assessment showed that a projected increase in the demand and production of foods of livestock origin with optimistic economic growth between 2010 and 2030 leads to an improvement in food security. However, resulting transitions in land use impact negatively on the future provisioning of ecosystem services, increasing phosphorus, nitrogen, and sediment in runoff and reducing water quality in areas downstream of the agricultural expansion. Losses in ecosystem services are lowest when diversified farming practices are adopted in areas of agricultural land expansion. The role of land management in the environmental impacts of expanded livestock production is highlighted, as is the need for a new generation of analytical tools to inform policy recommendations.

EDITORIAL article Front. Vet. Sci., 23 May 2023Sec. Veterinary Epidemiology and Economics Volume 10 - 2023 | https://doi.org/10.3389/fvets.2023.1208023

PurposeAgricultural aggregation schemes provide numerous farmer-facing benefits, including reduced transportation costs and improved access to higher-demand urban markets. However, whether aggregation schemes also have positive food security dimensions for consumers dependent on peri-urban and local markets in developing country contexts is currently unknown. This paper aims to narrow this knowledge gap by exploring the actors, governance structures and physical infrastructures of the horticultural value chain of Bihar, India, to identify barriers to using aggregation to improve the distribution of fruits and vegetables to more local market environments.Design/methodology/approachThis study uses mixed methods. Quantitative analysis of market transaction data explores the development of aggregation supply pathways over space and time. In turn, semi-structured interviews with value chain actors uncover the interactions and decision-making processes with implications for equitable fruit and vegetable delivery.FindingsWhilst aggregation successfully generates multiple producer-facing benefits, the supply pathways tend to cluster around urban export-oriented hubs, owing to the presence of high-capacity traders, large consumer bases and traditional power dynamics. Various barriers across the wider enabling environment must be overcome to unlock the potential for aggregation to increase local fruit and vegetable delivery, including informal governance structures, cold storage gaps and underdeveloped transport infrastructures.Originality/valueTo the best of the authors’ knowledge, this study is the first critical analysis of horticultural aggregation through a consumer-sensitive lens. The policy-relevant lessons are pertinent to the equitable and sustainable development of horticultural systems both in Bihar and in similar low- and middle-income settings.

Animal-source foods (ASF) are an important source of nutrients in many developing countries. However, there is limited information on the demand for ASF and the factors influencing their consumption. This study assessed spatial and temporal patterns of ASF consumption in Tanzania using data from a nationally representative household survey. Price and expenditure elasticities of ASF demand were estimated by applying a censored Quadratic Almost Ideal Demand System (QUAIDS) model. Results showed a 30% increase in weekly household expenditure on ASF from USD 3.02 in 2008 to USD 3.94 in 2014. The likelihood of a household purchasing ASF was 4.5 percentage points higher in urban compared to rural areas. With the exception of dried fish, the expenditure elasticity of ASF demand was positive and statistically significant. Expenditure and own-price elasticities were largest for chicken and lowest for dried fish. The responsiveness of ASF demand to own-price changes was higher in rural than urban areas in all cases. The findings imply that public policies that either raise household incomes or lower ASF prices have the potential to increase the consumption of ASF and consequently improve food and nutrition security in Tanzania. [EconLit Citations: C33, D12, Q18].

African Swine Fever (ASF) causes high mortality and often results in strict culling policies for affected pigs and international market restrictions. It took more than 25 years for swine inventories in Haiti and the Dominican Republic to recover from an ASF outbreak that took place from 1978 to 1984. The 2021 outbreaks in the Dominican Republic and Haiti pose threats to animal health, livestock markets, and producer livelihoods. A partial equilibrium Haitian pig sector model (HPM-2021) was developed to assess the economic impacts of a 2021 Haitian ASF outbreak of a similar size to the 1980s outbreak. The dynamic model examines ASF impacts from 2021 to 2024, through 100 iterations of stochastic supply shocks, and three specific demand shocks. Recovery alternatives are assessed through 2030, and outbreaks and recovery outcomes are compared to a baseline reflecting 2019 trends. The analysis includes economic effects on national pork and maize in Haiti, the Dominican Republic, the rest of the Caribbean, and the rest of the world. Findings demonstrate higher vulnerabilities of the traditional sector to ASF-related disruptions. The inflated prices generated by pork production shortfalls are an opportunity to accelerate income growth for remaining traditional pig producers. When there is no consumer avoidance, the production losses caused by ASF generate high prices and contribute to a minimum of 49% increase in traditional sector revenue, and a minimum of 2.22% revenue growth in the commercial sector from the 2019 base year. Nevertheless, the potential for consumer avoidance of pork cause prices to decrease and offset those gains by as much as 90% in the traditional sector and 44% in the commercial sector. Smaller commercial sector impacts derive from different elasticities. ASF-induced high prices also lead to increased consumer expenditure losses by up to 200% over the outbreak period. Nevertheless, consumer expenditures tend to recover instantaneously with ASF eradication. Due to persisting demand shocks, producers will earn up to 0.3% lower than baseline levels income from 2027 to 2030. Few models evaluate the economic impacts of health response policies in less developed countries like Haiti. HPM-2021 results highlight ASF impacts on prices, which can benefit certain producers and disincentivize on-farm disease reporting. Slow recovery and consumer avoidance of pork are detrimental to long-term swine industry survival, producer livelihoods, and the overall rural economy.

This document is part of a series of short papers on “The Future of X”, produced as part of foresight-related research supported by the CGIAR Research Program on Policies, Institutions, and Markets, and edited by Keith Wiebe (IFPRI) and Steven Prager (Alliance of Bioversity and CIAT). These short papers are intended to provide a focused, forward-looking perspective on key issues to support discussion on food, land, and water systems transformation. We thank two anonymous reviewers for their comments on an earlier draft.This is an accepted version presented as a pre-print. It is currently undergoing final revision, editing, and production. A final version will be made available at http://foresight.cgiar.org.

Peste des petits ruminants (PPR) is a devastating livestock disease that predominantly affects small ruminants (sheep and goats), with morbidity and mortality up to 90%, and it significantly affect men and women whose livelihood depend on livestock. In this study, we highlight key findings from an assessment of the potential economy-wide impacts of PPR in Ethiopia and Burkina Faso. A pair of social accounting matrices (SAMs) of both countries were deployed and analysed through multiplier effects. A multiplier captures how a one monetary unit change in a sector may affect that sector and the overall economic activity in terms of gross domestic product (GDP), sectoral GDP, employment and household income. Our analysis considered a 5% shock in the value of small ruminant (SR) output to simulate the hypothetical outbreak whose prospective impacts are presented below. Key results • In Ethiopia, the hypothetical 5% shock in the value of SR would reduce GDP at factor cost (before taxes) by 0.34%, or USD326 million, considering its 2019 GDP. Nearly 220,000 jobs (or -0.5% of total employment) would also be lost, with losses concentrated in the SR sector and some crop production sectors like sorghum, barley and maize. The value of lost downstream sectors outputs would range from -0.01% for public administration to -0.32% for other non-agricultural industries. • In Burkina Faso, the same hypothetical shock would reduce GDP at factor cost by 0.62% (i.e. over USD98 million) considering the GDP in 2019. It would further cause a contraction in the value of SR by 5% while reducing maize and rice production value by over 0.5% and 0.65% for the other cereals. About 0.39% of all jobs (i.e. about 22,000 jobs would be lost) with losses concentrated in the SR sector and across various crop production sectors, including maize (0.49%), rice (0.51%) and other cereals (0.59%). September 2021 ILRI RESEARCH BRIEF 102

Rising per capita consumption, economic growth, and urbanisation, particularly in developing countries, have been driving an increased global demand for food. These changing socio-economic trends, which have greatly influenced changes in dietary patterns globally and, more specifically, have increased consumption of livestock products in developing countries, are expected to endure and to place new pressures on livestock-sector infrastructure and the delivery of veterinary services. This paper summarises current trade in meat and presents plausible projections for the future. It highlights the impact of animal disease on trade and considers the effect of ongoing disease outbreaks, particularly the outbreaks of African swine fever and COVID-19, on current and future trade dynamics. The authors analysed published statistics on the demand for, and international trade in, livestock products at national and regional levels and made projections of the same up to 2050, generated from an integrated model of the global agricultural and food system. The resulting analyses identified patterns of trade consistent with growing populations, increasing incomes and changing diets in developing countries. The analyses also pointed to slow expansion of livestock production, and the impacts of countries' disease status on livestock trade. For most of the livestock products analysed, economic model projections indicate increased consolidation of production and exports among a few countries. Marked increases in the trade in livestock products suggest a changing role for Veterinary Services in facilitating trade and extension in the years to come.

Objective: This paper examines the ex-ante impacts of on-farm diversification and forward integration strategies on agricultural value chain resilience, with an empirical focus on Ghana's cocoa value chain. Method: System dynamics modelling was used to explore five scenarios involving variable-input on-farm diversification pursued by cocoa farmers in Ghana and the simultaneous adoption of forward integration stra-tegies by Ghana and Cote d'Ivoire. Results and Conclusions: An adaptive strategy involving the simultaneous pursuit of variable-input on-farm diversification and a cooperative forward integration strategy by both Ghana and Cote d'Ivoire was found to result in the highest level of resilience. Under such an adaptive strategy, in-country processors will be the most impacted when the level of safety stocks are below 25% of the average stock level during the period of losses in raw material production. Significance: The findings suggest that a policy direction that supports on-farm diversification and in-country processing enhances the aggregate resilience of the cocoa value chain, irrespective of the forward integration strategy adopted by Cote d'Ivoire.

Small-scale pig farming is highly important to the economic and social status of households in Timor-Leste. The presence of an African Swine Fever (ASF) outbreak in Timor-Leste was confirmed in 2019, a major concern given that around 70% of agricultural households practice pig farming. This research used a virtual spatial group model building process to construct a concept model to better understand the main feedback loops that determine the socio-economic and livelihood impacts of the ASF outbreak. After discussing the interaction of reinforcing and balancing feedback loops in the concept model, potential leverage points for intervention are suggested that could reduce the impacts of ASF within socio-economic spheres. These include building trust between small-scale farmers and veterinary technicians, strengthening government veterinary services, and the provision of credit conditional on biosecurity investments to help restock the industry. This conceptual model serves as a starting point for further research and the future development of a quantitative system dynamics (SD) model which would allow ex-ante scenario-testing of various policy and technical mitigation strategies of ASF outbreaks in Timor-Leste and beyond. Lessons learned from the blended offline/online approach to training and workshop facilitation are also explored in the paper.

The Market Intervention for Nutritional Improvement (MINI) project aims to understand the barriers and trade-offs associated with increasing the delivery of fruits and vegetables (F&V) to smaller, often less lucrative markets in Bihar, India and Jessore, Bangladesh. As a first step in our project research, we conducted a rapid food value chain analysis (RFVCA) in Bihar to: (i) identify key value chain actors, interlinkages and functions distributing F&V between farm and fork, (ii) conceptualise the flows of F&V, including barriers to equitable F&V distribution, and (iii) scope opportunities to adapt aggregation towards the needs of consumers in semi-rural/rural markets.

In recent decades there has been a sustained and substantial shift in human diets across the globe towards including more livestock-derived foods. Continuing debates scrutinize how these dietary shifts affect human health, the natural environment, and livelihoods. However, amidst these debates there remain unanswered questions about how demand for livestock-derived foods may evolve over the upcoming decades for a range of scenarios for key drivers of change including human population, income, and consumer preferences. Future trends in human population and income in our scenarios were sourced from three of the shared socioeconomic pathways. We used scenario-based modeling to show that average protein demand for red meat (beef, sheep, goats, and pork), poultry, dairy milk, and eggs across the globe would increase by 14% per person and 38% in total between the year 2020 and the year 2050 if trends in income and population continue along a mid-range trajectory. The fastest per person rates of increase were 49% in South Asia and 55% in sub-Saharan Africa. We show that per person demand for red meat in high-income countries would decline by 2.8% if income elasticities of demand (a partial proxy for consumer preferences, based on the responsiveness of demand to income changes) in high-income countries decline by 100% by 2050 under a mid-range trajectory for per person income growth, compared to their current trajectory. Prices are an important driver of demand, and our results demonstrate that the result of a decline in red meat demand in high-income countries is strongly related to rising red meat prices, as projected by our scenario-based modeling. If the decline in the income elasticity of demand occurred in all countries rather than only in high-income countries, then per person red meat demand in high-income countries would actually increase in 2050 by 8.9% because the income elasticity-driven decline in global demand reduces prices, and the effect of lower prices outweighs the effect of a decline in the income elasticity of demand. Our results demonstrate the importance of interactions between income, prices, and the income elasticity of demand in projecting future demand for livestock-derived foods. We complement the existing literature on food systems and global change by providing quantitative evidence about the possible space for the future demand of livestock-derived foods, which has important implications for human health and the natural environment.

The need for food systems to generate sustainable and equitable benefits for all is a global imperative. However, whilst ample evidence exists linking smallholder farmer coordination and aggregation (i.e. the collective transport and marketing of produce on behalf of multiple farmers) to improved market participation and farmer incomes, the extent to which interventions that aim to improve farmer market engagement may co-develop equitable consumer benefits remains uncertain. This challenge is pertinent to the horticultural systems of South Asia, where the increasing purchasing power of urban consumers, lengthening urban catchments, underdeveloped rural infrastructures and inadequate local demands combine to undermine the delivery of fresh fruits and vegetables to smaller, often rural or semi-rural markets serving nutritionally insecure populations. To this end, we investigate the potential for aggregation to be developed to increase fruit and vegetable delivery to these neglected smaller markets, whilst simultaneously improving farmer returns. Using an innovative system dynamics modelling approach based on an aggregation scheme in Bihar, India, we identify potential trade-offs between outcomes relating to farmers and consumers in smaller local markets. We find that changes to aggregation alone (i.e. scaling-up participation; subsidising small market transportation; mandating quotas for smaller markets) are unable to achieve significant improvements in smaller market delivery without risking reduced farmer participation in aggregation. Contrastingly, combining aggregation with the introduction of market-based cold storage and measures that boost demand improves fruit and vegetable availability significantly in smaller markets, whilst avoiding farmer-facing trade-offs. Critically, our study emphasises the benefits that may be attained from combining multiple nutrition-sensitive market interventions, and stresses the need for policies that narrow the fruit and vegetable cold storage deficits that exist away from more lucrative markets in developing countries. The future pathways and policy options discovered work towards making win-win futures for farmers and disadvantaged consumers a reality.