Introduction

Areas of agricultural intensification and changing climatic conditions have been identified as ‘hotspots’ for disease activity, due to shifts in disease distribution and increased contact rates between humans, wildlife, and livestock and the costs associated with those risks (Jones et al., Reference Jones, Patel, Levy, Storeygard, Balk, Gittleman and Daszak2008). In the past decade, researchers have studied the response of disease vectors, animal hosts, and pathogens to climate change (Heffernan et al., Reference Heffernan, Salman and York2012). Increase in extreme rainfall is speeding the transport and transmission of water-borne pathogens (Patz et al., Reference Patz, Graczyk, Geller and Vittor2000). Climate change appears to be exacerbating existing diseases such as zoonotic tuberculosis (Mycobacterium bovis) (Clifford et al., Reference Clifford, Kazwala, Coppollilo and Mazet2008). Increase in the unpredictability and severity of rainfall patterns and temperature extremes are limiting resource availability, thereby narrowing the window of management options available for modulating disease impacts.

While we have an understanding of the health risks and economic costs of infectious and endemic disease events, we have only just begun to identify the possible public health benefits of sustainable landscapes and the potential health savings accrued from disease avoidance (MEA, 2003). To date, few studies have attempted to quantify the health benefits attributable to sustainable agro-ecosystems, especially in regard to livestock systems in regions impacted by climate change such as East and West Africa and South Asia.

Therefore, in the following article, I will discuss the role and impact of sustainable livestock production on public health. Two production systems frame the analysis: pastoralism versus intensive, small-holder systems. Sustainability in this context refers to the ‘maintenance of the quantity, as well as the quality of agricultural produce (in this case livestock) over very long periods of time without fatigue’ (Kesavan and Swaminathan, Reference Kesavan and Swaminathan2008). Therefore, a sustainable livestock system steadily provides livestock products without compromising the health of the agro-ecosystem. A system is unsustainable if low productivity perpetuates poverty, and the animals and people are chronically malnourished and in poor health. Health and wellbeing are fundamental to sustainability because they contribute to resilience, allowing livestock holders to be less vulnerable to socioeconomic and climatic shocks.

Increasing population pressures, changes in land tenure, and increasing climate variability are presently challenging the health and integrity of agro-ecosystems (Daszak et al., Reference Daszak, Cunningham and Hyatt2001). Human perturbations are shifting host–pathogen dynamics, reminding us that health outcomes are interconnected. If the health of one community is compromised, other communities are likely to be affected, spreading infectious disease. Pastoralism can amplify some disease risks through increased contact among wildlife, livestock, and humans. While effective range management may minimize health risks by mitigating climate change impacts and providing ecosystem services. For smallholder systems, disease risk can be high while effective management has the potential to increase economic growth in tandem with improved health outcomes.

Across both systems, there is a livelihood spectrum i.e. pastoralists who rely solely on rain-fed rangelands to those communities who are largely sedentary. Equally, smallholder intensive systems range from subsistence to semi-commercial operations. Livelihood transition across these spectrums is not only a socioeconomic transformation but also signals different human interactions within the agro-system. Understanding these transitions is critical because some of the most important impacts on human health may occur during the transition between livelihood states. For example, researchers have linked expansion of agriculture and changes in agricultural practices to Nipah virus emergence in Malaysia (Lam and Chua, Reference Lam and Chua2002).

Because of the increasing uncertainty related to socioeconomic and climatic conditions, pastoralism in some semi-arid regions may no longer be viable or sustainable. The increasing intensity and frequency of extreme weather events (EWEs) affects the quality and quantity of available forage, which in turn affects the mobility patterns of pastoralists (Boko and Niang, Reference Boko, Niang, Parry, Canziani, Palutikof, Van Der Linden and Hanson2007). In semi-arid regions of East and West Africa, the ecological patches that have provided respite from long periods of drought are now scarce and crowded with livestock, thus increasing disease transmission rates (Mazet et al., Reference Mazet, Clifford, Coppolillo, Deolalikar, Erickson and Kazwala2009).

However, pastoralists face limited options for adapting their management strategies to weather extremes (Little, Reference Little2012). One option is to change mobility patterns, but these shifts may move pastoralists farther away from markets and into conflict over limited resources. Another option is to change the type of livestock (e.g. from large to small ruminants). A third option is to restrict animals to residential areas with zero-grazing and some form of nutrient-rich feed. Nevertheless, across all of these options there is scope for sustainable production over the longer-term, as defined above. Pastoralism helps preserve ecosystem services while taking advantage of limited resources by converting grass to animal protein and milk in semi-arable regions (Gill et al., Reference Gill, Smith and Wilkinson2010). Using this as a starting point, development activities must recognize and support sustainability issues across the spectrum of both traditional and transitional livelihood activities.

Farmers in smallholder intensive systems face a range of other challenges. As the demand for meat continues to grow in South Asia and Africa and access to communal sources of water and forage shrinks, intensification of small-scale livestock systems in peri-urban areas is expected to expand (FAO, 2010). In South East Asia, smallholder transition to livestock intensification has been transformative, increasing economic opportunities while also introducing new disease risks and increasing demand on limited resources (Rushton et al., Reference Rushton, Viscarra, Taylor, Hoffmann and Schwabenbauer2010).

The inherent challenges involved in the intensification of smallholder mixed crop-livestock systems have led to advocacy for sustainable intensification from an ecosystem services perspective, delivering more animal-source, nutritious food per unit of input resource while not further degrading the ecosystem services that are necessary for sustaining human health and wellbeing (FAO, 2010; Smith, Reference Smith2012). Options for sustainable intensification focus on improving efficiency in use of resources such as water and feed (Wirsenius et al., Reference Wirsenius, Azar and Berndes2010). While the focus has been primarily on efficiencies, the health benefits in terms of nutritious foods and other determinants of health have yet to be fully explored.

Calculating the health benefits and health savings is important for communicating the services that a sustainable agro-ecosystem can provide. For example, some studies have shown that mobile pastoralists achieve better nutritional outcomes for their families because of higher quality milk and meat production when livestock have access to lands that are not as intensively used (Fratkin et al., Reference Fratkin, Roth and Nathan2004; Pedersen and Benjaminsen, Reference Pedersen and Benjaminsen2008). However, for the information to be actionable, it is important to identify the key points along the livestock livelihood spectrum where agro-ecosystem capacity could be strengthened to provide sustainable return in terms of health and economic gain. This knowledge is especially important to the least well-off livestock holders who may benefit from assistance as they transition from one livelihood state to another in an effort to adapt to changing socioeconomic and climatic conditions. It is also helpful to compare differences in health benefits and health savings among different livelihood options for livestock holders.