ADAPT-HERD - Management strategies to improve herd resilience and efficiency by harnessing the adaptive capacities of small ruminants

There is increasing recognition of the value of livestock farming in less favoured rural areas, not only for their contribution to rural economy and social structures but also for their environmental role in closing elementary cycles, e.g. stimulating carbon capture in permanent pastures, etc. (Bernués et al., 2011; Bénagabou et al., 2017). In this context small ruminant systems in the Mediterranean area have a key role to play that depends upon finding a durable balance between system resilience and efficiency. This balance will differ according to the local environments, and is likely to change as the impacts of climate change are fully felt. So far, improving efficiency has been generally achieved by increasing production level, leading to a dilution effect of fixed production costs. However, this strategy can easily lead to resilience erosion. There are few studies that quantify this potential trade-off between efficiency and resilience, and almost all considered integrated (or mixed) crop-livestock systems and focused on diversification of activities within the farm (Kahiluoto and Kaseva, 2016; Gil et al., 2017). ADAPT-HERD will go beyond the state-of-the art in exploring the relationship between R&E in livestock systems, by simulating a wide range of herd management situations, under various climate scenarios. Animal adaptive capacities are a key leverage point to improve R&E at the herd level (Dumont et al., 2014). This explains the focus of on-going projects on the selection of this composite trait and its implementation in breeding programs. The main issue with adaptive capacity lies in its complexity: i) this highly polygenic trait combining a large number of underlying mechanisms and ii) this trait is sensitive to the dynamic interplay between environment and time. Despite recent advances in characterizing the genetic determinants of adaptive capacities (Ha et al., 2017), the underlying physiological components remain largely unknown. ADAPT-HERD will improve our understanding of adaptive capacities by experiments that combine divergently selected lines and nutritional manipulations. Systemic modelling has been shown to be an indispensable tool for achieving a quantitative understanding of how components interact within complex systems (at molecular level see Marchadier et al., 2011; at herd level, see Tichit et al., 2009). ADAPT-HERD builds on a highly innovative systemic model in the domain of understanding trade-offs in livestock (Puillet et al., 2016) and will substantially advance the state-of-the-art by deploying this within a herd-level model. A small number of herd-level models of small ruminant production exist (Guimaraes et al., 2009; Puillet et al., 2010; Douhard et al., 2014) but to date none of these have the capacity to both model trade-offs and to include the accumulated effects (through life) of environmental perturbations on herd-level performance and resilience. This will be a key function of the proposed ADAPT-HERD prediction tool.

The overriding concept behind ADAPT-HERD is that improving R&E at herd level will contribute to improve R&E at the farm level and therefore will be a key element of adaptation of small ruminant systems to climate change. Given the complex balance of mechanisms giving rise to efficiency and resilience, there is no single solution that fits all and that will maximize both efficiency and resilience in a range of situations. The challenge is to find strategies that are good enough in terms of efficiency, to ensure sufficient income for farmers, and also good enough in terms of resilience, to ensure farm sustainability. In other words, the challenge is not to find an optimal strategy for R&E, but to explore how management strategies impact the relationship between R&E. Simulation tools, allowing “what if” scenarios to be evaluated would be extremely useful to assess the R&E costs and benefits of different management strategies under current condition, and also under future changing conditions. Small ruminants are recognized for having strong biological mechanisms to deal with constraining and fluctuating environmental conditions, particularly with respect to feeding resources (Silanikove, 2000; Atti et al., 2004). Our approach considers that such adaptive capacities can be fully integrated within management strategies to improve R&E at the herd level by: - Using different reproduction practices to manage the temporal distribution of herd size and herd make-up (proportions of young and adult animals) that provides the best match between feed supply (itself varying in time depending on quantity and quality dynamics of the local resources such as grasslands, rangelands, crops, by-products) and overall herd demand (depending on the sum at any given time of individual requirements) - Managing groups of animals in the herd based on their types of adaptive capacities and thereby targeting interventions to face resource shortage (e.g. extra feed distribution) to groups with the greatest potential to respond, reducing the total cost of intervention - Managing herd demography and adapting animal numbers to feed resource with locally-tailored replacement and culling practices that consider not only market conditions but also the continued viability of the herd In our approach, we emphasize the need to combine information from both the animal and the herd levels in order to harness adaptive capacities with herd management strategies. At the animal level, we will capture a comprehensive view of adaptive capacities by combining a fine-grained experimental approach, evaluating mechanisms and trade-offs at the biological function level, with a field phenotyping approach evaluating the responses of locally adapted breeds to their real conditions of feed availability. Information will be combined within a modelling framework based on energy acquisition and allocation. The theoretical basis for describing life-history strategies in terms of energy allocation is well established in evolutionary biology and has been shown to apply to a wide range of species (e.g. Stearns 1992, Reznick et al. 2000, Roff et al., 2002). This framework has been imported in livestock sciences (van der Waaij, 2004) where it offers several advantages: it is generic enough to represent different breeds in various contexts (and therefore be the basis for a common shared architecture); it provides an explicit representation of resource allocation trade-offs among biological functions (e.g. reproduction and survival) and lifetime trajectories, from birth to herd exit. At the herd level, individual variability in the herd will be simulated by using a cluster of individual animal models within the herd model (individual-based approach). This biological variability will be combined with operations on the herd, representing farmer’s practices, and with feed resource dynamics, representing the local constraints.

ADAPT-HERD will improve the ability of Mediterranean sheep and goat systems to adapt to climate change by providing herd management solutions based on animal adaptive capacities. The project will deliver locally tailored practical solutions for herd management to optimise production and resilience of the herd to minimize farmer risk in the face of constraining and changing environmental conditions. These solutions will be specifically oriented toward: - Early-life nutritional strategies to safeguard adult adaptive capacity - Reproduction management as a way to match temporal distribution of feed supply and herd demand - Tailored group-feeding based on type of animals to face acute challenge (feed shortage) - Management of herd demography (replacement and culling) to adjust feed demand in anticipation of critical periods