Environmental footprint of heavy pig production system

This study assessed the environmental footprint of the heavy pig production system in Northern Italy, through a Life Cycle Assessment cradle-to-farm gate model, in order to identify practices along the production chain (breeding, post-weaning and fattening phases) possibly associated with the environmental footprint of herds. Data originated from 18 farms (8 breeding farms – 1052±576 sows, 30.1±3.8 weaned piglets/sow per year – and 10 fattening farms - 3522±1996 places, 170±8 kg body weight (BW) at the sale with 181±13 days/production cycle). For each farm, data on animal and manure management, feedstuff production, and use of energy sources were collected as an annual average. The functional unit was 1 kg BW sold. Global warming (GWP), acidification (AP) and eutrophication (EP) potentials and land occupation (LO) were considered as impact categories. Partition of impact between sows and piglets was based on an economic allocation method. Impact values per production phase were analyzed with linear models to test the effects of farm management (farm size, feed self-sufficiency), ration composition (protein and phosphorus content) and animal responses (weaned piglets/sow/year, replacement rate, average daily gain, feed conversion ratio) variables. The production of 1 kg BW (cradle-to-farm gate) was associated with the emissions of 2.94±0.36 kg CO2-eq (GWP), 55.6±5.6 g SO2-eq (AP) 22.3±3.0 g PO4-eq (EP) and the occupation of 3.49±0.84 m2/y (LO) on average. Manure management and feed production significantly contributed to all the impact categories and for all the production phases. Farm management traits tenderly affected only the fattening phase: increasing farm size was associated with increasing GWP and increasing self-sufficiency with lower AP and EP. The dietary composition had a very low influence on the impact categories. Increasing productivity (weaned piglet/sow and year) was associated with lower GWP values in the breeding phase. Productivity gains (average daily gain and feed conversion ratio) seemed to mitigate all the impact categories in the post-weaning phase but not in the fattening one. In conclusion, the farm systems investigated showed good performance and low variability in terms of impact values. Differences in management practices among farms were limited and slightly associated with differences in emissions. Therefore, new mitigation practices for lowering the environmental footprint of such production systems need to be explored.