Managing carbon in livestock systems: modelling options for net carbon balance (SARDI)

Summary

This study investigated greenhouse gas (GHG) emissions (tonnes of carbon dioxide equivalents; t CO2e) and emissions intensity (t CO2e/t carcase weight) of pasture-fed southern beef production systems by simulation modelling. Reasons for differences in yield and composition of GHG emissions and the effects of mitigation strategies were investigated.
Using the SGS Pasture Model the GHG emissions intensity of self-replacing beef cattle breeder operations were estimated at 16.33 to 18.61 t CO2e/t calf carcase weight, mostly from methane. Trader/finisher cattle systems produced GHG emissions intensities of 10.83-12.79 t CO2e/t steer carcase weight. Through manipulation of grazing management and making full use of the production potential of animals it was possible to reduce total GHG emissions from breeder operations by 12.2% while also increasing total calf carcase weight produced. Within trader/finisher operations, reductions in GHG emissions were found when either growth efficiency of animals was increased (up to 5% reduction) or maintenance efficiency was decreased (up to 4% reduction). When both effects were applied concurrently there was up to an 8.8% reduction in total GHG emissions intensity.
​Thus it appears that grazing management and genetic selection are both viable means for livestock producers to reduce GHG emissions from their enterprises.