How agroecological transition can jeopardize compliance with Protected Designation of Origin specifications: a living lab case study in Fourme de Montbrison cheese

Agroecological transition has recently emerged as a key strategy to help address changing climate and societal demands, but little is known about its effect on animal-derived products, including in Protected Designation of Origin (PDO) dairy products. A case in point is Fourme de Montbrison (FM) PDO cheese, a blue-type cheese from the French Massif Central, where an ongoing farm agroecological transition project (switching cows to a pasture-based diet and switching from Holstein to Montbéliarde breed) led to an increase in the rate of low fat in DM content nonconformities in the cheese. The aim of this research, co-conceived with stakeholders in a living-lab approach, was to identify the origin of the low fat in DM content issue and to test possible solutions to reduce the number of nonconformities. Through a series of meetings with stakeholders, we identified 2 possible problematic steps in the production process that may work together to reduce cheese fat in DM content: i) cheesemaking process at a processing level; ii) milk production at farm level. At processing level, we sampled 36 vat milks, the vat-milk whey after cheesemaking, and the ripened cheeses for chemical composition analysis. Milk fat and nitrogen composition were found to be the major determinants of fat in DM content in FM cheese. At farm level, we studied 2 groups of 10 farms: one group where milk-fat-to-protein-ratio (FPR) was frequently low (FPR-), and one where it was not (FPR+). Farming practices were recorded via a survey, and bulk milk and grazed herbage were sampled twice per farm for chemical composition analysis. Proportion of Holstein-breed cows and Montbéliarde-breed cows in the dairy herd were positively and negatively related to milk FPR, respectively. Herbage composition analysis suggested that FPR- farms applied a more intensive rotational grazing system, offering young-growth herbage that was highly digestible and rich in protein and water-soluble carbohydrate but low in physically effective NDF, resulting in lower milk fat content and FPR. Subsequent discussions with stakeholders identified 4 possible solutions: increase fiber content in the spring-season cow diet by i) supplementing hay at pasture using a mobile hay rack or ii) delaying the utilization of herbage until a later phenological stage; iii) introduce some Jersey-breed cows into the herd to increase milk fat content; or iv) slow the concentrate transit rate and fermentation by substituting corn cob silage with corn flour. Solution 'iv' was the only solution that stakeholders considered feasible. It was tested on 4 FPR- farms that were then compared against 4 equivalent farms that continued running their usual practices. Changing the type of concentrate has no effect on milk composition. The living-lab approach was found to effectively increase stakeholder participation and engagement, but the process of co-constructing experiments may lead to practices being tested that do not effectively solve the studied problem. Agroecological transition may induce long-term and often unexpected effects on product characteristics, which means that deeper research is warranted.