The contribution of crop-livestock systems to the rural economy of the Mediterranean basin is huge and exceeds direct food production. In southern Europe, these systems are essential for producing animal products (e.g. typical cheeses) with high added value that safeguard local economies, while protecting the agricultural environment and the rural landscape in various respects (limitation of soil erosion and hydrogeological risk; maintenance and improvement of fertility, structure and water-holding capacity of the soil; efficient nutrient cycling, etc.: Peeters, 2009; Turner et al., 2011). In the west-Asian and north-African (WANA) region, small farmers adopt crop-livestock systems because of the crucial importance of animal rearing as a buffer against economic shocks or crop failures and the opportunities that they offer for spreading labour and re-utilizing farm resources (Delgado et al., 1999; FAO, 2010). Also high-protein annual feed crops, which are particularly important for semi-intensive or intensive animal rearing (e.g. poultry productions), have a positive environmental impact (Carrouée et al., 2003) and can be pivotal for cost- and energy-efficient cropping systems (e.g. in Australian dry areas: Turner et al., 2011).

The countries on the southern rim of the Mediterranean basin are characterized by an increasing demand for livestock and poultry products that is caused by the growing population and the high nutritional value of these products (Delgado et al., 1999; FAO, 2010). For example, Maghrebian countries (Algeria, Morocco, Tunisia) featured a mean production increase of 218% for cattle milk and 91% for chicken meat over the period 1994-2009 (http://faostat.fao.org). The inability of local forage and feed production to keep pace with the increasing demand is leading to alarming levels of feed import (FAO, 2010). For example, the average amount of imported soybean cake in Maghrebian countries increased by 302% over the period 1994-2008 (http://faostat.fao.org). Fodder production in the WANA region is largely based on permanent grasslands and, besides being insufficient, is progressively declining because of overgrazing and the consequent desertification (FAO, 2010). Concentrate feed, which could increase the production of livestock (especially when providing a limiting nutrient factor such as protein: Dixon and Stockdale, 1999) and alleviate indirectly the overgrazing, is mostly limited to poultry productions because of its high costs and wide price variation in international markets.

Also European countries feature a remarkable insufficiency of concentrate feed, especially for high-protein feedstuff, whose alarming level has recently been acknowledged by a resolution of the EU parliament (INI/2010/2111 of March 8, 2011). For example, soybean cake is currently the first imported agricultural commodity in France and the second in Italy (http://faostat.fao.org).