Milk production was estimated to contribute with 3-4% of the anthropogenic 11 GHG emissions. However, several differences can be found in the carbon footprint 12 associated to raw milk depending on several factors, such as the geographical area, 13 species of cow and production system. In this work, a global overview of works 14 published on CF of raw cow milk is provided. Additionally, two different dairy systems 15 (semi-confinement and pasture-based) have been analysed by Life Cycle Assessment 16 (LCA) in order to determine the effect on the CF of milk produced. High quality 17 inventory data was obtained directly from these facilities and the main factors involved 18 in milk production were included (co-products, livestock food, water, electricity, diesel, 19 cleaning elements, transport, manure and purines management, gas emissions to air…). 20 In accordance with reviewed literature, it was found that the carbon footprint of milk 21 was basically determined by the cattle feeding and cow gas emissions. The values of 22 milk CF found in the systems under study were within the range for cow milk 23 production worldwide (0.9-4.7 kgCO2eq/kgFPCM). Specifically, in the semi-confinement 24 and the pasture-based dairy farms 1.22 and 0.99 kgCO2eq per kgFPCM were obtained, 25 2respectively. The environmental benefits obtained with the pasture grazing system are 26 mainly due to the less use of purchased fodder but also to the allocation between milk 27 and meat that resulted to be a determinant methodological issue in CF calculation.
28Finally, data of the evaluated dairy systems have been employed to analyse the 29 influence of raw milk production on cheese manufacturing. With this aim, CF of a 30 small-scale cheese factory has also been obtained. The main subsystems involved were included (raw materials, water, electricity, energy, cleaning products, packaging 32 materials, transport, wastes and gas emissions) were included in the inventory of the 33 cheese factory. CF values were 16.6 and 14.7 kgCO2eq per kg of cheese for milk 34 produced in semi-confinement and pasture-based systems, respectively. The production 35 of raw milk meant more than 60% of CO2eq emissions associated to cheese, so the 36 primary production is the principal hot-spot to reduce the GHG emissions derived from 37 cheese making.
