Greenhouse gases in cattle breeding : evaluation and mitigation strategies

Abstract

In today's environmental context, as much political (the reduction of greenhouse gas emissions) as social (consumer demands forinformation concerning food products), there is a need to determine the influence of ruminant livestock on climate change. It hasbecome crucial to quantify precisely the levels of greenhouse gas emissions (GHG) and carbon sequestration for different ruminantlivestock systems by using Life Cycle Assessment (LCA) to calculate the carbon footprint of dairy and beef farms. This approachallows us to account for GHG in relation with direct and indirect emissions. Thus in the French dairy system, the average grosscarbon footprint is 1.26 kg CO2 /kg milk. Carbon sequestration under grassland and hedges compensates for GHG emissions rangingfrom 6 to 43% according to the system utilized. Consequently the net carbon footprint is 1.0 kg CO2 / kg milk. In the Frenchbeef system, the gross carbon footprint for raw materials is comprised between 14.8 and 16.5 kg CO2 / kg of live meat depending onthe production system. It must be mentioned that carbon sequestration represents compensation in a range of 24 to 53% and the netcarbon footprint is between 7.9 and 11.3 kg CO2 / kg of live meat. These investigations demonstrate that numerous mitigation actionshave been identified in the livestock systems to reduce the carbon footprint of milk and meat at the farm gate. Some of them concernmanagement practices (adjustment of dietary intake, fertilization management…) which result in substantial savings in agriculturalexpenses. Others require the installation of new technologies which would require additional funds to improve the productionprocesses.