Environmental and socioeconomic benefits of a division of labour between lowland and mountain farms in milk production systems

Swiss mountains and lowlands feature different climatic and topographic conditions for agricultural production. Thus, farmers developed a collaborative dairy production scheme, where they take advantage of the specific environment of the two regions. In this contract rearing system, the young stock is reared on a mountain farm and the more intensive milk production is performed in the lowlands. This system is an example for the principle of comparative advantage, where each region focuses on the activity where it has the lowest opportunity costs. We hypothesised that the same principle can also be applied in an environmental context, to reduce the environmental impacts of agricultural production. Based on the life cycle assessments of average dairy farms, we could show that the absolute environmental impact was higher on mountain farms for both, the production of one heifer for restocking and the production of one kg milk. However, they had a comparative environmental advantage for rearing, as the young stock was better suitable for their local conditions than the dairy cows. Therefore, milk produced in collaboration between lowland and mountain farms had an up to 4.5% lower non-renewable energy demand and used up to 30.9% less potassium and up to 5.2% less phosphorus resources compared to non-collaborative production. Further consequences of collaboration were a reduced workload and income on mountain farms, and a potentially increased income on lowland farms. We conclude that the principle of comparative environmental advantage is appropriate as a screening method to identify suitable production systems for less favoured regions. However, the total effects of a possible division of labour among regions need to be assessed in a more holistic way where possible side-effects on other aspects are considered as well.