Carbon footprint of milk from Holstein and Jersey cows fed low or high forage diet with alfalfa silage or corn silage as the main forage source

Our objective was to determine the cradle-to-farmgate carbon footprint of fat-and-protein corrected milk (FPCM) for four diets fed two breeds using measured enteric methane and greenhouse gas emissions during manure storage after field application. The were formulated as 2 × factorial with forage neutral detergent fiber at levels (19 24% diet dry matter referred low high diets, respectively) from sources (70:30 or 30:70 ratio alfalfa silage corn silage). Measured incorporated in a modeled Wisconsin dairy farm herd consisting 118 lactating cows (primiparous), 22 cows, 119 heifers. Emissions allocated between meat biophysical allocation, sensitivity analysis performed impact alternative allocation methods. Overall, 1.43 kg CO2-e/kg FPCM 1.50 1.60 economic no (100% milk), respectively. Forage source did not influence results. However, forage-fed had 10% greater than (1.49 vs. 1.35 FPCM). Assuming similar structure, Holsteins 4.4% Jerseys (1.47 1.41 Accounting differences fertility replacement rate increased difference 10%. Under our study conditions, due fermentation minimal but became substantial when combining effects cow (enteric CH4) (CH4 N2O) emissions. These exacerbated even further accounted associated on-farm feed production purchased (CO2 N2O). This highlights need an integrated approach assess dietary manipulations on footprint.