1. Global Farm Platform: Steps to sustainable livestock Energy efficiency measures for livestock production John Webster University of Bristol, Emeritus

2. We may take it as read: Meat production at a rate to feed the present and future rich is unsustainable BUT Grasslands, shrub and parklands comprise ca 70% of the world’s agricultural area. Ruminants produce large quantities of methane BUT Permanent pastures and (especially) silvo-pastoral systems are net C sinks

3. METHODOLOGY: Measures of energetic efficiency of livestock production Feed energy – Competitive and complementary Metabolizable Energy Life cycle assessments – Metabolizable energy plus fuel energy Embedded energy (“emergy”)

4. Efficiency of utilization of ME (total and competitive) (Webster 1994) EggsPorkMilkBeef Production unit1 hen22 pigs1 cow1 calf Support unit0.05 hens1 sow0.33 heifers1 cow Output/year (kg food)1513008000200 Food energy (MJ)13013000280002500 Input/year: total ME (MJ)389670386708929850 'competitive' ME (MJ)351536302012710268 Efficiency Food energy/total ME0.330.190.420.08 Food energy/'competitive' ME0.350.241.390.24

5. Life cycle analysis: Energy inputs (after Pelletier et al 2010) Output (1 tonne meat) Energy use (GJ) ME total ME competitiveFuel energy Broiler chickens363214.9 Pork, commercial52419.7 Pork, niche684911.4 Beef, feedlot finished1495184.2 Beef, pasture finished19420114.2

6. Embodied energy, (Emergy) = available energy (e.g. seJ) consumed directly or indirectly in transformations to make a product or provide a service Renewable energy (R) Livestock production Food (etc) Y Unrenewable energy Purchased goods (NR) and services (F)

7. “Emergy” analysis Emergy yield ratio (EYR) = (R+NR+F)/F – >EYR = > contribution of local resources (“land”) to product Environmental load ratio (ELR) = (NR+F)/R – > ELR = > ratio of non-renewables to renewables in product Emergy sustainable index – EYR:ELR (yield: environmental compatibility)

8. Emergy indices for different food production systems from Rotolo et al 2007 EYR = (R+NR+F)/F, ELR = (NR +F)/R, ESI = EYR/ELR EYRELRESI Corn (USA)1.0718.80.06 Soya (chemical, Brazil)1.743.400.50 Soya (organic, Brazil)1.781.401.27 Conventional pig (Sweden)1.0422.30.05 Organic pig (Sweden)1.137.800.15 Grazing cattle (Argentina)3.730.556.80

9. Summary without conclusions All arguments (including these) are based on incomplete premises Energy transformations provide an effective measure of the efficiency of livestock production Livestock production efficiency increases with increasing use of complementary ME. Sustainability of livestock production can be assessed by “Emergy sustainable index” (yield: environmental compatibility)