Does organic livestock husbandry uses less energy and produces less greenhouse gas than conventional husbandry? Analysis in lactating sheep farms

We have undertaken in this work an evaluation of the greenhouse gas (GHG) emissions and the Non-Renewable Energy (NRE) consumption on a sample of 1250 farms-years, operating in sheep meat production, in either organic (OA) or conventional (CA) agriculture, over the period 1987 to 2012, based on the Life Cycle Assessment (LCA) method. There was no significant difference for NRE consumption (79.6 MJ in OA and 79.7 MJ in CA, per kg of carcass); indeed the gains in OA thanks to a lower use of chemical fertilizers and purchase of lesser concentrates feed were offset by the higher level of mechanization (here fuels and equipment). For GHG emissions, we found a significant difference of 5% beneficial to organic production systems (31.1 vs. 32.7 kg CO2 eq/kg carcass).