Decreasing environmental footprints of dairy production systems through optimization of feed rations and origins

Summary

Environmental impacts of livestock production systems are a global concern, because of the large greenhouse gas (GHG) emissions and nitrogen (N) and phosphorus (P) losses associated with feed production and livestock rearing. These losses are in part related to the system of livestock production and their feed rations and feed origin. This study aims to investigate the economic and environmental impacts of optimizing feed configurations of dairy farms in Inner Mongolia (China), using data from farm surveys, life cycle assessments and linear optimization programming. The findings of our study reveal that feed optimization may lower carbon footprints by 36–44%, nitrogen footprints by 35–42%, and phosphorus footprints by 42–71%, compared to the baseline. The need for cropland decreased by 11–38% per kilogram of milk, feed costs decreased by 15–48%, and net profit increased by 39–129%. Further, we found a statistically significant negative correlation between environmental footprints and feed self-sufficiency of dairy farms. Notably, energy-rich feeds, silage maize, and grass should be grown on-farm. These findings underscore the potential of adjusting feed rations and origin to decrease environmental footprints and enhance net profits of dairy farms. However, we observed several barriers to widespread adoption of optimal feed rations and origin, which relate to land scarcity, high land rental costs, and lack of trust and cooperation with nearby arable farms. Our research provides a scientific foundation for optimizing feed rations and origins for diverse dairy systems to achieve improved environmental and economic performance.