Parameters affecting the carbon footprint of milk at the farm gate

The latest assessment report (2014) of the Intergovernmental Panel on Climate Change (IPCC) identified anthropogenic green- house gas (GHG) emissions at the highest levels ever achieved and estimates the emissions from the livestock sector at 7.1 giga- tons of CO2 eq per year, 14.5 % of the total global anthropogenic GHG emissions. To address the issue at the Italian milk sector, a survey on 61 dairy farms located in the Po Valley was carried out. The contribution of raw milk to GHG emission has been estimated with the Life Cycle Assessment (LCA) a methodology that under- pins sustainable development in food production. The aim of the research was to perform the carbon footprint (CF) of milk pro- duction at the farm gate (cradle-to-farm-gate) without consider- ing the transport, processing and distribution of milk. Primary data were collected for one year and the CF calculation was per- formed according to the IPCC guidelines. The functional unit used to report GHG emissions was 1 kg of carbon dioxide equiv- alents (CO2-eq) per kg of FPCM at the farm gate. Meat was considered as a co-product. The environmental impacts were grouped into five main categories: purchased feeds, produced feeds, farm consumption, enteric fermentation, livestock manure. SimaPro© v8.0.5 and SPSS were used as modelling and statistical software, respectively. Dairy farms were classified according to the herd size and type and source of feeds being used in animal feeding. Expanding and restricting herds were not considered as this could bias the total CO2 eq allocation either to meat or milk. Thus, 52 out the original 61 farms were considered in the LCA analysis. Results showed that of the 1.187 kg CO2 eq per kg of Fat-Protein Corrected Milk (FPCM), 43.3 % were due to enteric fermentation, 29.1% to feed purchased, 14.6% to manure (9.5, 3.0, 2.1 % for CH4, N2O direct emission and N2O indirect emission, respectively), 8.2% to feed production (2.7, 1.4, 4 % for CO2 from fertilisers, CO2 from diesel, N2O from fertilisers, respectively), 4.5% other purchase (3.1, 0.08, 1.3 % for CO2 from electricity, CO2 from other energies and other CO2, respectively). The CO2 eq per kg of FPCM was similar to the emissions esti- mates in European and North American farms (about 1.3 kg of CO2 eq/kg of FPCM).