• enteric fermentation
• ,LCA
• beef cattle
• mediterranean
• Eeissions
• GHG

Livestock is one of the main sectors of agriculture, creating employment and sustaining livelihoods in Europe. Since world population is projected to reach 9.8 billion in 2050, and 11.2 billion in 2100, the global demands for livestock products will increase facing natural resource scarcity and major challenges posed by climate change. Cattle are the main contributor to the livestock sector’s emissions with about 4.6 gigatonnes CO2-eq, depicting 65 % of total livestock emissions. Beef cattle and dairy cattle generate similar amounts of GHG emissions (Gerber et al., 2013). The goal of the “Low-carbon livestock strategy” (LCLS) is to produce healthy food in a way that minimizes the overall output of GHGs into the atmosphere, by the understanding of the diversity and complexity of livestock agrifood systems (FAO 2019). Recently, Latawiec et al. (2014) reported that agrosilvopastoral systems can increase productivity and sustainability of animal products. In fact, these systems are able to provide several benefits such as, mitigation of greenhouse gas emission from livestock sector, increment of the adaptability of livestock to the climate change effects, and improvement of the nutritional quality of animal-derived food. Currently in southern Tuscany, Maremmana breed rearing is still conducted by the utilization of the understory forage production. Moreover, the improving of microclimatic conditions under the tree canopy are able to improve the thermal comfort of cattle, especially during summer (heat stress) and winter (thermal excursion). The purpose of this study was to estimate the environmental impact of Maremmana beef cattle reared on an agrosilvopastoral production system and to assess whether CO2 sequestration by forest ecosystems involved in such production were a valid mitigation option to LCLS.
The study was conducted at the “Tenuta di Paganico” organic farm, Paganico, Italy (42.954N, 11.238E) in an area characterized by Mediterranean climate conditions with mean annual temperature of 15°C and an average annual rainfall of about 800 mm (2003-2014). The beef cattle production is conducted according to semi-extensive cow-calf operations and pasture-based fattening. The reference year was 2018. The study is a cradle-to-farm gate farm-based life cycle assessment (LCA), meaning that all relevant data are primary and all relevant pre-slaughterhouse activities are taken into consideration: from feed production (machinery, seeds, irrigation, etc.) to grain milling, electricity, and fuel consumption. All feeds are produced on-farm and the cattle are allowed to graze freely all year round, depositing urine and dung on the soil (there is no manure management system nor manure spreading). The impact of on-farm transportation of feeds and off-farm transportation of external inputs were also taken into consideration.
Cows and heifers (n=47) with calves (n=33) and one bull, and steers with heifers (n=27) were able to graze under the canopy of a high forest (mainly Quercus cerris L.) that covered an area of 570 ha. Therefore, this woodland surface was included in the LCA. Carbon (C) removals and fuel use owing to harvest operations of wood products were also included, while to account for the C sink, the average forest growth rate of oaks was derived from the Tuscany Regional Forest Inventory (www.regione.toscana.it). Indeed, forests within the farm are managed according to a pluriannual silvicultural management plan. Moreover, the entire herd was allowed to graze on 50 ha of temporary grassland but C sink activity of pasture was not included. Grassland do have a strong potential to partly mitigate the GHG balance of ruminant production systems but soil C sequestration is both reversible and vulnerable to disturbance (Soussana et al., 2010), and there is still great uncertainty about the size, distribution and activity of this sink (Gerber et al., 2013). The software used was OpenLCA (GreenDelta, Berlin - Germany), while for life cycle inventory (LCI) background data, a combination of LCI databases was used, namely Ecoinvent (version 3.7.1), Agrifootprint (version 5), and Agribalyse (version 3.0.1). One kilogram of live body weight sold (LBW) was used as the functional unit and in order to conduct the life cycle impact assessment, the EPD® method (2018) was used.
The assessment of the global warming potential (GWP) of organic Maremmana beef meat produced in
a semi-extensive agrosilvopastoral system in Tuscany was 8.05 kg CO2 eq per kg of LBW. Our study
highlighted that without taking into account the mitigation effect of the C sink of woodlands grazed by
cattle, the GWP was 22.44 kg CO2 eq per kg of LBW. In the investigated livestock system, C sequestration
by grazed woodland allowed to mitigate a large portion of the overall GHGs emitted by meat
production. As reported in Fig. 1, the largest contributor to GWP was enteric fermentation followed by
manure management and crop cultivation. Aiming to cope with climate change, the woodland
ecosystem positively acted mitigating 64% of the GHGs emitted by a semi-extensive meat production
system. However, further research and a standardized methodology will be necessary to include
grassland ecosystems in such calculations and to assess the other environmental benefits of
agrosilvopastoral systems towards low-carbon livestock productions.