Life Cycle Assessment on Changing Dietary Strategies of a Non-grazing Dairy Production System in Hokkaido, Northern Japan

抄録

This study explored the impact of changing dietary strategies on dairy animal productivity and the environment. We used the life cycle assessment (LCA) method to examine the effectiveness of different dietary strategies for reducing methane (CH₄) and carbon footprint (CF) in dairy cows. The simulated dietary strategies encompassed diets of varying hay-concentrate ratios: H100:C0; H80:C20; H75:C25; H50:C50 and H30:C70, respectively. The results confirm that CH₄ and CF from dairy cows can be reduced by 40% depending on the nature of the intervention and prevailing conditions of the study area. The LCA method demonstrated that CH₄ and CF reduction primarily depends on milk productivity and an optimized hay-concentrate ratio (H80:C20). The findings suggest that dairy farm CF calculations should consider milk yield in their analyses. This study illustrates that LCA comprehensively estimates greenhouse gas (GHG) emissions beyond ruminal methane production while identifying trade-offs in GHG emissions due to CH₄ reduction.