Liquid whey recycling within the traditional dairy chain, as a sustainable alternative for whey waste management

The world production of cheese whey, which is the main contaminant generated by the cheese industry, is estimated to be over 108 tons/y. In Italy, the cheese production in 2013 was 1.166 ton. Thanks to its nutritional value, liquid whey can be successfully recycled in animal nutrition. Following the LCA methodology, this study aims to assess the environmental impact of milk production within the traditional dairy chain. In three farms, different cow’s diets were assessed and compared: farm A, with hay and no liquid whey; farm B, including silages but no liquid whey; farm C, including both silages and liquid whey. Finally, sensitivity analysis was conducted on allocation methods (mass vs. cereal unit) between milk and meat. Results have shown that farm C had the best environmental performance due to both silages/liquid whey use and milk yield per cow (29 L vs 28 L in farm B and 25.1 L in farm A). The same results were achieved in the cereal unit allocation, even if the mass allocation results were higher than those with cereal unit allocation. The identification of critical impacts along the production cycle and the comparison among the three cow’s diets suggest those best practices that could improve the milk production sustainability in marginal areas typical in South Central Italy.