Key practices affecting the environmental impact of Ewe milk in mixed farming systems

This study examined management practices in twelve Mediterranean mixed dairy sheep farms to identify key drivers of environmental impacts associated with milk production. Using life cycle assessment and multivariate analysis, the study explored correlations between farm management practices and environmental outcomes. The average annual milk production was consistent with existing literature, reaching 190 kg of fat and protein corrected milk (FPCM) per ewe. The correlation analysis revealed a general trend indicating that the various impacts considered, such as atmospheric emissions, acidification, and eutrophication, increased proportionally. Specifically, a greater reliance on concentrates for animal supplementation was linked to higher environmental impacts, suggesting that the use of purchased feeds tends to worsen the environmental performance of mixed dairy sheep farms. Principal component analysis further highlighted that environmental impacts were positively correlated with increased electricity consumption and higher fuel use per hectare. Conversely, grazing practices were associated with reduced environmental impacts, emphasizing the advantages of pasture mass as an energy-rich feed source in contexts where preserved forages are of poor quality due to adverse climate conditions. Regarding global warming potential (GWP), the study found that enteric methane emissions from ruminants accounted for over 53.5 % of total emissions. The average GWP was estimated at 4.2 kg CO2eq kg−1 of FPCM. The use of detailed equations for estimating biogenic GWP underscored the importance of accurate data collection on livestock characteristics, diet composition, intake, and feeding duration.