availability,  high  flexibility).  Increasing  requirements  of the market regarding food quality, safety and traceability will limit small-scale farmer participation in certain value chains. Further, access to market may be limited by inad­equate infrastructure, such road systems and refrigerated transport and storage.
      Successes in value chain development have been achieved through an extensive consultation processes (Bernet et al., 2005) that generate group innovations based on well-led and well-structured participatory processes. These processes stimulate interest, trust and collaboration among members of the chain. The costs and benefits of such approaches will have to be carefully assessed to determine where investment is justified; e.g., investments for upgrading the market chain could be high compared with potential benefits for niche products with limited market volume.

6.2 Improve Productivity and Sustainability of Livestock Systems

On-farm options
Mixed systems. Mixed crop-livestock systems can contrib­utes to sustainable farming (Steinfeld et al., 1997). Improv­ing the performance of mixed crop-livestock production systems and promoting livestock production, particularly on small-scale farms can be attained by providing access to affordable inputs for small-scale livestock keepers. Along with inputs, adequate knowledge and technologies for on-farm nutrient cycling, on-farm production of feed and fod­der, and the use of crop residues and crop by-products, can also provide benefits to small-scale producers.
      Intensifying the livestock component in these systems increases the availability of farmyard manure, leading to increased  fodder  production  and  increased crop  yields. More research is needed on the storage and application of farmyard manure, the conservation of cultivated fodder and crop residues, and the use of crop by-products as animal feed.
      Livestock keeping can improve health and nutrition in many small households and generate additional income and employment (ILRI, 2006), even when households have limited resources such as land, labor and capital (PPLPI, 2001; Bachmann, 2004). Output per farm may be small, but the combined effect of many small-scale enterprises can be large, e.g., small-scale dairy in India (Kurup, 2000), pig­gery in Vietnam (FAO, 2006) and backyard poultry in Af­rica (Guye, 2000).

Extensive systems. There is little scope for extensive live­stock production systems to further extend the area pres­ently being grazed without environmentally unsustainable deforestation (Steinfeld et al., 2006). In some areas even pasture land is decreasing as it is converted into cropland, often resulting in land use conflicts  (ECAPAPA, 2005). Where pasture areas with open access remain more or less stable, productivity of land and ultimately of livestock is threatened due to overstocking and overgrazing.
       Livestock productivity can be increased through the im­provement of pasture and rangeland resources and better animal health. Better animal health may require improved access to veterinary services, such as the establishment of sys-

tems of community based animal health workers (Leonard et al., 2003). Feeding conserved fodder and feeds (primarily crop by-products) may help overcome seasonal shortages, while planting fodder trees, more systematic rotational graz­ing and fencing may improve grazing areas. Tree planting may gain further importance when linked to carbon trade programs. Fencing, on the other hand, may not be socially or culturally acceptable, in particular in areas with communal grazing land (IFAD, 2002). Land use strategies that include participatory approaches are more effective at avoiding con­flicts (ECAPAPA, 2005).
      Biological complexity and diversity are necessary for survival in traditional pastoral communities (Ellis and Swift, 1988). Long term conservative strategies often work best in traditional systems. The introduction of new breeding techniques (e.g., sexing of sperm straw) might cause a rapid increase in the number of cattle, but may also lead to the disappearance of local breeds and a reduction in the genetic diversity of rustic breeds of cattle, which are well adapted to extreme environments.
      The overall potential of pastoral grazing systems is high (Hesse and MacGregor, 2006); the primary issue is the en­vironmental sustainability of these systems (Steinfeld et al., 2006). Hence options to improve productivity must focus more on the application of management than the technology (ILRI, 2006).

Intensive systems. Increasingly, intensive livestock produc­tion trade is associated with a fear of contamination of air and water resources (de Haan et al., 1997; FAO, 2006). Fu­ture systems will need to consider human health aspects as well as the whole livestock food value chain (fodder and animal feed production, processing and marketing of prod­ucts, etc). Since cross-regional functions such as assembly, transport, processing and distribution can cause other ex­ternalities, they must be assessed as part of an integrated system. Intensive systems are prone to disease and animals can spread zoonotic diseases like tuberculosis or bird flu that can affect humans (LEAD, 2000).
      Improvements in intensive livestock production systems include locating units away from highly populated areas, and using management practices and technologies that mini­mize water, soil and air contamination.

6.3 Breeding Options for Improved Environmental and Social Sustainability

6.3.1 Crop breeding
Climate change coupled with population growth will pro­duce unprecedented stress on food security. Abiotic stresses such as drought and salinity may reduce yields worldwide by up to 50% (Jauhar, 2006). Increasing demand cannot always be met by increasing the land devoted to agriculture (Kumar, 2006), however, it may be possible to improve plant pro­ductivity. Traits that are the focus of abiotic stress resistance include optimized adaptation of temperature-dependent en­zymes (to higher or lower temperatures), altering day-length regulation of flower and fruit development, optimization of photosynthesis including circumventing inherent limitations in C3 and C4 pathways in plants (Wenzel, 2006).