Carbon footprint of milk produced at Italian buffalo farms

Abstract

The carbon footprint (CF) of milk produced in six Italian Mediterranean Buffalo farms was estimated through a simplified Life Cycle Assessment. Functional unit was 1kg of fat and protein corrected milk (FPCM).The farms were characterized by high levels of inputs, as purchased feeds, chemical fertilizers and fossil fuels. Average cultivated area was 53.2ha; the forage system was based mainly on maize silage, immediately followed by Italian ryegrass and/or whole cereal silage. Average herd size was 360 and the average FPCM per lactating buffalo was 3563kg/year with an average milk fat and protein percentage of 8.24 and 4.57 respectively. The CF assessment was from cradle to farm gate. The greenhouse gases (GHG) that were taken into account were CH4 from enteric fermentations, CH4 from manure in the stable and in the tank; N2O from nitrification and denitrification processes in the manure before application into the soil and N2O produced after organic and synthetic fertilizer application; direct emissions of CO2 from the fossil fuels combustion within the farms and indirect emissions of CO2 deriving from production of electricity, off-farm feeds, synthetic fertilizers and other minor inputs. Carbon footprint of 1kg of FPCM was 3.75kg CO2eq. Main sources of GHG are enteric CH4 (45%) and indirect CO2eq (25%). Besides enteric CH4, the farm activity that gives the highest contribution to milk CF is on-farm feed production, with 34% on total greenhouse gas emissions (TGE). Carbon footprint with economic allocation (CFea) was estimated by considering the live-weight of males calves and culled cows: its value was 3.60kg CO2eq. If the economic value of the increase of the herd size is considered in the assessment, CFea decreases to 3.45 or 3.27kg CO2eq with an increase of 10% or 20% of the number of mature buffalos.