Caracterización y valorización de la ganadería pastoral de pequeños rumiantes de razas autóctonas a través del análisis de su sostenibilidad y la calidad de sus productos

Résumé

Given the current global crisis, it is essential to promote sustainable development in all areas, including agriculture and livestock production. Extensive livestock farming linked to the territory, in particular small ruminant grazing systems based on autochthonous breeds, plays a central role in the management and conservation of High Conservation Value Areas (HCVA). In addition, this activity is extremely important from a social perspective, because it contributes to the creation of employment, and, at the same time, it has a sociocultural impact, maintains the aesthetics of the landscape and supports tourism. Furthermore, different studies have shown that both milk and meat obtained from grazing systems have optimal quality for consumer health. However, these systems are in risk of disappearing due to the lack of profitability of the activity and the limited generational replacement. Therefore, the aim of this Doctoral Thesis is to generate knowledge about the management of these systems, their profitability, the quality of their products and their environmental impact, as well as to propose improvements that guarantee their conservation, taking as an example the Payoya goat systems at Andalusia and the Mallorquina sheep systems at Balearic Islands. Two studies were conducted with Payoya goat grazing farms: a previous study with 8 farms from June to October 2010, which was extended with a second study with 16 farms during 2011. In both, technical and economic information was collected monthly, especially regarding their feeding management, while milk samples were collected from the tank for quality analysis. In Mallorca, a third study was carried out with seven Mallorquina sheep grazing farms from which technical and economic information was collected monthly during 2015 and, from October to December of the same year, a total of 50 male lambs were selected for quality analysis of carcass and meat. Among the different results obtained in the analysis conducted with grazing goat farms, we highlight how the optimization of grazing resources entails a reduction in dependence on external inputs and production costs, which allows farms to achieve a satisfactory level of productivity and profitability. Mallorquina sheep farms are not very specialized and they are very heterogeneous between them; they show great differences in feeding management and marketing. Although, in these farms, the feeding self-sufficiency is high, the lack of profitability jeopardizes their continuity. Regarding environmental analysis, we can conclude that, to reduce the carbon footprint in grazing dairy goat farms, it is important to reach an adequate level of milk production and minimize use of external inputs. Even so, this indicator should be studied in a broader context, and other functional units, such as hectares used, should be considered. The contribution of pastoral systems to soil carbon sequestration should also be considered. Regarding quality of obtained products, we can highlight that higher grazing level improve functional quality due to favourable variations in the levels of some desirable healthy FA (lower PUFA content, higher content of some n-3 FA and lower n-6 total, most optimal ratio n-6/n-3) and α-tocopherol. In addition, important differences were found according to the season of the year, being possible to discriminate milk samples based on it, which could be used by the sector as a traceability tool and to differentiate the product in the market. On the other hand, Mallorquina lambs show good carcass quality and nutritional quality. No large differences were found between commercial weights. However, differences due to feeding management were found, obtaining a more favourable lipid profile (lower content in PUFA and higher in SFA, higher content in CLA and n-3 FA and more optimal ratio n-6/n-3) in lambs of pastoral systems without concentrate supply (milk and pasture), which is the traditional management. Taking into account both key aspects of these systems (sustainability and benefits), a series strategies are proposed aimed at maintaining an adequate level of feeling selfsufficiency, improving farm profitability and promoting and valuing the ecosystem services of this type of livestock. To preserve this system it is necessary to conduct further research aimed at identifying their social and environmental benefits.