Strategies to mitigate the environmental footprints of meat, egg and milk production in northern China

The livestock sector contributes significantly to resource use and pollution in food systems. Therefore, assessing and reducing the environmental impacts of livestock production under different farming systems has become an important area of solution-oriented research in sustainability sciences. A case study in northern China on beef cattle, pig, broiler, layer and dairy farm systems was used to analyze the water footprint (WF) and N emissions in producing units of products from cradle-to-farm-gate based on the life cycle assessment (LCA) approach. Possible ways to change feed components and manure management to reduce environmental impacts were assessed. The results showed that 98.1%–99.4% of the water consumption in beef, pork, chicken, egg and milk production was from feed production. The N losses in livestock products were mainly caused by ammonia (NH3) emission by 53.8–83.5%, nitrous oxide emission by 6.4–17.3%, and N leaching by 6.1–16.8%. Life cycle assessment indicated that the green, blue, grey and total WFs of livestock products could be reduced by 9.9–31.4%, 21.6–70.6%, (−9.8)-38.0%, and 14.7–32.4%, respectively, by optimizing the feed composition. Changing feed composition, improving housing facilities (such as by using padded floor for beef cattle, pig, and dairy farm systems), using household biogas facilities to treat manure or coupling all of the above strategies could reduce the nitrogen footprint (NF) by an average of 29.4%, 4.6%, 16.2% and 43.2%, respectively, for all farming systems. Changing feed composition, using a padded floor and using household biogas treatment on manure were effective practices in reducing water consumption and nitrogen emissions from livestock farming systems, with an overall positive influence on reducing the overall WF and NF for livestock systems in northern China.