Carbon footprint of intensive vs. extensive dairy farming in Gargano area

Carbon footprint is an indicator of environmental sustainability quantifying the greenhouse gas (GHG) emissions generated by the individual or collective activities. Two dairy farms located in Foggia province (CaseStudy1, CS1; CaseStudy2, CS2) both raising Mediterranean buffaloes (B) and crossbred Italian Friesian cows (C) with different management systems (intensive vs. extensive) were studied to investigate the impacts of milk production. Data about herd characteristics (live weights, mortality, fertility, production), diets composition, and manure management of dairy buffaloes (n = 136 vs. n = 78, CS1B and CS2B respectively) and dairy cows (n = 44 vs. n = 31, CS1C and CS2C respectively) were collected to evaluate the GHG emissions on a year basis according to FAO assessment model (GLEAM-i ver 1.9, https://www.fao.org/gleam/resources/en/). Considering the global warming potential (GWP) of buffalo farms, the more extensive system in CS2B was found less impactful than the intensive CS1B, showing −33.7% of total GHG emissions (expressed as kg CO2-eq/year) and −50.8% of total CH4 (expressed as kg CH4/year). Both feed intake (kg DM/year) and milk production (kg/year) were lower in CS2B (−48.3% and −52.7 % respectively), so that it resulted more impactful (+42.5%) when milk emission intensity (kg CO2-eq/kg protein) was considered. The total N2O emission (kg N2O/year) was +56.7% in CS2B due to the different manure management. Regarding the dairy cow farms, CS2C was found less impactful in terms of both total GHG and CH4 (−21.1% and −37.5% respectively) emissions. Feed intake and milk production were lower in CS2C (−32.4% and −36.9% respectively), resulting the milk emission intensity higher (+25.8%) than in CS1C. Consistently with emissions in buffalo farms, the total N2O emission was higher (+56.6%) in the extensive system. Data processing suggested that GHG emissions were closely related to feed production practices, diet composition and manure management in the different farms. On this regard, formulating diets that match the nutritional animal requirements, improving feed digestibility and availability, introducing alternative protein source or by-product, and implementing manure and animal waste processing, could allow a more sustainable use of natural resources, limiting the potential negative environmental impacts while preserving farm remunerability.