Modelling the national cattle herd to simulate meat and milk production and the greenhouse gas emissions inventory

Assessing the environmental impacts of cattle production raises the issue of handling the meat co-produced from milk production. The objective of the study was to develop a model of the national cattle herd in France that encompasses both meat and milk production and tests the effect of different technical orientations (breed, productivity and finishing type) on the direct greenhouse gas (GHG) emission inventory. The model was used to test dairy intensification (increase in Prim’Holstein milk yield), increased use of a dual-purpose breed (Normande) and beef intensification (increase in young bull and steer finishing types) under a scenario of constant milk and meat outputs. The results showed that dairy intensification slightly decreased GHG emissions when the number of calves per cow did not decrease (-2.03%). Using the Normande breed led to a slight increase in GHG emissions (+0.99%), except when veal production was replaced by beef production due to the dual purpose of this breed, which decreased GHG emissions (-4.01%). Finally, increasing the young bull finishing type led to the strongest decrease in GHG emissions (-4.66%), whereas increasing steer finishing was associated with a slight increase in GHG emissions (0.65%). This model demonstrated that inventory GHG emissions are more sensitive to the method of meat production than to dairy intensification