The aim of this study was to analyze the relational social structure of the cheese factories based on an agribusiness territory of Mexico through social network analysis (SNA) in order to understand how different types of agroindustries coexist and endure. Participant observation and semi-structured interviews were carried out in 17 cheese agribusinesses located in the area of San José de Gracia, Michoacán (Mexico), in order to get insight into the family, inter-company, commercial and technical ties they have built. The SNA showed that in the community there is a meso-system where different cheese companies that produce either natural, imitation or both cheeses converge and coexist. These agroindustries make up a complex social structure composed of 1717 actors, comprising a dispersed network with low connectivity (density ˂0.5%) due to the commercial nature of the relationships (95.9%). Simultaneously, an underlying network with a higher density (1.73%) was also evident, enriched by kinship and friendship ties that create cooperation and trust among the parties through 136 reciprocal tangible and intangible exchanges. Despite the differences and asymmetries of cheese agribusinesses in this community, the social structure they form behaves like a ‘local neighborhood’ where everyone knows everyone, and everyone coexists, competes and shares with one another, allowing them to be sustainable in the marketplace. This study provides important lessons for institutions that promote competitiveness and local development, because it shows that in order to achieve sustainability of agroindustrial companies, it is important to recognize and promote long-term social structures based on trust, friendship and reciprocity.

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Palabras clave: metano, desechos orgánicos, producción de gas, bioenergía, residuos vegetales RESUMEN La creciente demanda de alimentos en áreas urbanas genera cada vez mayor cantidad de desperdicios orgánicos, incluyendo residuos vegetales. El manejo de estos residuos vegetales causa emisiones de gases efecto invernadero (GEI) por su recolección, transporte, y depósito en vertederos. Para identificar su potencial de GEI, en un mercado de alimentos se recolectaron residuos de hojas de lechuga (LS), de col (BOV), de coliflor (BOB), de maíz (HZM), de espinaca (SO) y de nopal (OF), se fermentaron in vitro usando líquido ruminal como inóculo y se compararon con heno de avena (AS), heno de alfalfa (AH) y ensilado de maíz (EZM), forrajes utilizados con frecuencia en la alimentación de rumiantes. Las variables fueron degradación in vitro de la materia seca (DIVMS), pH, cinética de producción de gas y concentración de metano (CH4). La fermentación se realizó durante 96 h a 39 ºC y las muestras de gas para medir la concentración de CH4 se tomaron a 9, 12, 24, 34 y 48 h de incubación. La DIVMS de LS, BOV, BOB, HZM y OF fue 12.8 % mayor a AS, AH y EZM. Entre las 9 y 12 h de incubación la emisión de CH4 a partir de BOV, BOB and HZM fue 44.8 % superior a los tres forrajes. La principal conclusión es que estos residuos vegetales son degradados adecuadamente por los microorganismos ruminales y, por lo tanto, se pueden usar para la producción de biogás en áreas urbanas para disminuir su depósito en vertederos.Key words: methane, organic wastes, gas production, bioenergy, vegetable residues ABSTRACTThe growing demand for food in urban areas generates an increasing amount of organic wastes, including vegetable residues. The management of these wastes can lead to greenhouse gases emissions (GHG) through its process, including collection, transportation, Rev. Int.

The objective of this study was to identify the technological level used by dairy farmers in the northeastern region of Michoacán, Mexico, through a characterisation of small-scale dairy production units, as well as to learn about the socioeconomic conditions that have enabled them to survive in the current context. A semi-structured interview was applied to 114 production units, chosen by stratified random sampling. The interview included technological, production and socioeconomic aspects. Twenty-eight variables were initially explored and 12 were used for multivariate analysis, which included Principal Component Analysis, Hierarchical Cluster Analysis and K-means Cluster. The characterisation carried out showed that the production units that predominate in northeastern Michoacán have survived with a low technological level, having as strengths the diversification of their activities and the use of family labour. On the contrary, production units with a high technological level and high productivity are few and less diversified. This shows the need to generate differentiated public policies for each cluster, aimed at strengthening the aspects that have allowed them to survive and guaranteeing a market for their production, before promoting the use of technologies.

The dual-purpose bovine system represents 98.4% of the bovine livestock of Veracruz, the main cattle-producing state of Mexico. This system supplies calves to meat companies, a sector in which Veracruz has been the national leader in the last decade. The objective of the present study was to analyze the effect of the altitudinal zonation of farms on livestock technology and productivity in a microbasin of the Gulf of Mexico where small farms predominate. Structured interviews were applied to producers located in three altitudinal zones (at average altitudes of 50, 140, and 450 m, respectively, for lower, middle, and upper zones). Sample size was 135 farms having similar land surface (within a range of 15-22 ha). The results indicated multiple differences among farms located in the three zones. Farms in the middle and lower zones presented higher productive indicators than those in the upper zone. Differences in herd structure and management resulted in important differences in productivity, income, and profits in milk and calf production. We concluded from this study that altitudinal zonation in Veracruz had a clear effect on the differentiation of small farms, which are representative of dual-purpose cattle. The upper zone performs cattle activity under conditions with greater disadvantages in the analyzed region.