Environmental impacts of medium-scale pig farming at technical and economic optimum production weight in Mexico

Medium-scale pig production systems, which make up 30 % of Mexico's pig farms, face two key obstacles impacting their economic and financial performance. The first is the absence of a sales plan based on pigs' weight, which negatively affects both profitability and resource management. The second obstacle is inadequate waste management, which hampers efforts to mitigate environmental impacts generated by pig farms. Based on this criterion, this study aims to determine technical and economic optimum levels of a medium-scale pig farm and evaluate its associated environmental impacts. Based on the last farm sale weight (116.3 kg - base scenario), technical and economic optimum levels were estimated using a production function, resulting in a technical optimum of 155 kg and an economic optimum of 127 kg. An environmental assessment of the pig fattening process was carried out following the principles of the Life Cycle Analysis methodological framework. Using a cradle-to-farm gate perspective, and establishing 1 kg of live-weight pig as the functional unit. The results indicated that production at maximum weight level (155 kg), increased environmental impacts by 60 % to 75 % compared to the base scenario. In contrast, at the maximum economic benefit level (127 kg), environmental impacts increased by 5 % to 10 %. Feed production represented the largest contribution (over 74 %) in six impact categories. The results provide valuable information for medium-scale pig farms to mitigate the environmental burdens associated with the optimal production weight and to direct efforts towards achieving future economic and environmental efficiency.