The first goal of this work was the description of a model addressed to quantify the carbon footprint in Spanish autochthonous dairy sheep farms (Manchega group), foreign dairy sheep farms (foreigners group: Lacaune and Assaf breeds), and Spanish autochthonous dairy goat farms (Florida group). The second objective was to analyze the GHG emission mitigation potential of 17 different livestock farming practices that were implemented by 36 different livestock farms, in terms of CO2e per hectare (ha), CO2e per livestock unit (LU), and CO2e per liter of fat- and protein-corrected milk (FPCM). The study showed the following results: 1.655 kg CO2e per ha, 6.397 kg CO2e per LU, and 3.78 kg CO2e per liter of FPCM in the Manchega group; 12.634 kg CO2e per ha, 7.810 CO2e kg per LU, and 2.77 kg CO2e per liter of FPCM in the Foreigners group and 1.198 kg CO2e per ha, 6.507 kg CO2e per LU, and 3.06 kg CO2e per liter of FPCM in Florida group. In summary, purchasing off-farm animal feed would increase emissions by up to 3.86%. Conversely, forage management, livestock inventory, electrical supply, and animal genetic improvement would reduce emissions by up to 6.29%, 4.3%, 3.52%, and 0.8%, respectively; finally, an average rise of 2 °C in room temperature would increase emissions by up to 0.62%.
Keywords: carbon footprint; goats; milk; sheep; simulation model.