Day 3.2 livestock impact livestock gf_rome (2)
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This document provides an update on revisions made to the livestock module in the International Model for Policy Analysis of Agricultural Commodities and Trade (IMPACT) model. Key changes include: 1) Disaggregating livestock production systems to better represent heterogeneity. 2) Incorporating response functions so that meat and milk yields endogenously respond to changes in feed quantities and quality. 3) Accounting for total herd numbers, including replacement animals, and imposing explicit feed constraints. 4) Revising feed demand allocation to be responsive to feed prices and availability. Testing of the revised livestock module has shown promising results so far. Further validation and scenario analysis are planned in upcoming years.
Day 3.2 livestock impact livestock gf_rome (2)
- 1. An Update on the IMPACT-Livestock Module D. Enahoro, S. Nelgen, S. Robinson, D. Mason-D’Croz, Global Futures and Strategic Foresight Extended Team Meeting Arbitart Hotel, Rome 25 – 28 May, 2015
- 2. Outline •The IMPACT model & Livestock •Baseline and suggested changes •Livestock systems characterization •Yield response •Feed supplies •Herd growth representation •Feed demand allocation •Next steps
- 3. Re: The IMPACT Model System Climate models Macro- economic trends Crop models Water demand trends Hydrology, water basin management and stress models IMPACT multi- country, multi- market Outputs Source: Rosegrant et al., 2014 trade prices production yields harvested area Figure 1: IMPACT System
- 4. Livestock in IMPACT v 2.0 Sector Representation: • 6 commodities – beef, milk, chicken meat, lamb, pork, eggs • Supply modelled at level of food production units (FPUs) • Country-level demand responsive to income, population trends, commodity prices • Internationally-traded feed grains and concentrates IMPACT projections to 2050 (Rosegrant et al., 2012 ): • Expansion in demand for meat, dairy, cereals, livestock feeds • Higher prices of major agricultural commodities
- 5. Important Gaps Identified • Heterogeneity in production systems not recognized • Important livestock feed dimensions ignored • Non-accounting for feed constraints on sector expansion • Herd dynamics largely missing • Addressed in Msangi et. al., 2014 (using IMPACT v2.0) • v3.0 compatibility needed
- 6. Revisions to Livestock representation in IMPACT Original Specification Suggested Updates Supply response is relatively homogenous within countries Livestock supply disaggregated by system types (intensive/extensive) Livestock feed basket composed only of internationally-traded feeds (mostly coarse grains and meals) Pasture grasses, crop residues and occasional feeds added to livestock feeding possibilities Yield is exogenously determined, and does not respond to quantity or quality of fed rations Meat and milk response functions are endogenous, responding to changes in feed quantities and nutritive values Total herd size includes milk-producing and slaughtered meat animals only Total herd count includes replacement and/or follower herds in dairy and meat production Animal productivity only indirectly affected but not affected by feed availability through price effects Explicit feed-availability constraints imposed on animal productivity Source: Msangi et al., 2014 Table 1: Original specification of livestock in IMPACT and key changes to model
- 7. Global Livestock Production Source: FAO, 2011Figure 2: Global Livestock Production Systems
- 8. Production Systems Disaggregation in IMPACT Following Kruska et al., 2002; FAO, 2011 1. Rangeland-Based: •Hyper-Arid/Arid/Semi-Arid •Humid/Sub-Humid •Temperate/Tropical Highlands 2. Mixed (Irrigated and Rainfed): •Hyper-Arid/Arid/Semi-Arid •Humid/Sub-Humid •Temperate/Tropical Highlands 3. Urban 4. Other
- 9. Production Systems Disaggregation in IMPACT System-specific data for IMPACT 3.3: 1. Livestock populations – producer herds and stocks 2. Meat, milk, egg production per unit livestock 3. Per unit feed intake 4. Biomass availability in FPU-system
- 10. Distributions of Livestock Globally Fig 2: Distribution of Cattle in Livestock Systems in Developed Countries Fig 3: Distribution of Cattle in Livestock Systems in Developing Countries Fig 4: (Percent) Distribution of Sheep and Goat in Global Livestock Systems Mixed Rangeland Urban Other Mixed Rangeland Urban Other 0 10 20 30 40 50 60 Developed Countries Developing Countries Source: Havlik et al., 2011
- 11. System-Specific Yields Region Mixed Extensive Urban Other Beef Developed countries 239 82 126 105 Developing countries 66 (28) 52 (63) 78 (62) 56 (53) Bovine Milk Developed countries 8,323 6,273 5,515 5,826 Developing countries 2,794 (34) 1,388 (22) 2,165 (39) 2,067 (35) Shoat Milk Developed countries 1,619 632 1,989 2,284 Developing countries 729 (45) 433 (69) 616 (31) 733 (32) Table 2: Mean Yields of Meat (Kilograms / tlu / year) and Milk (Litres / tlu / year) by Global Livestock Production Systems Source: Authors’ own calculations from Havlik et. al., 2011
- 12. The Yield Response Equations ))(11( d fljdfljdfljflj XLogExpYH • Feed-responsive yields: Log-Linear and Quadratic functional forms )1(2 d fljdfljdfljflj XYH )2( d e fljefljdfljde XX For YH - meat/milk yields; α – yield intercept; β - coefficient on feed variable; X - feed intake in Mt/tlu/year; f – food production unit; l – livestock production system; j – disaggregated livestock commodity and d, e - feed variable for grains, pastures, residues and occasional feeds. Equation 1 is the default. Equation 2 is applied to the fpu-system-commodity subset for which it is empirically relevant. Eqn. 2. Revised Yield I Eqn. 3. Revised Yield II nittnitni YLgLYYL ,1)1( • The baseline yield equation with exogenous trajectory Eqn. 1. Exogenous Yield
- 13. Feed Response of Livestock Yields •Livestock production (in MTs per TLU per year) generated from work at ILRI and IIASA • Feed sources from four major categories: o Grains and residues (FAO feed commodities) o Residues o Grasses (grazing, cut-and-carry) o Occasional feeds (kitchen wastes, non- FAO) •Simulation data generated from RUMINANT livestock nutrition model •FPU-systems would not switch feeding regime in the projection years •“Sites” of production could shift with feed availability
- 14. Alternative Livestock Feed Supplies •Crop grain-residue conversion factors from ILRI/ICRISAT work (Blummel; Herrero et al.,) (QN is stover dry matter from crop type b, in FPU f and livestock system l ; QS is crop grain b production; c-, util-, and DM- fact are grain conversion, feed utilization, and dry matter factors, respectively) •Occasional feeds modeled in base year to bridge gap between feeds locally available, and animal nutrition dietary requirements •Pasture availability estimated from grassland area and productivity layers (Havlik et al., 2011) flbflbflbflb utilfactcfactQSQN flbDMfact Eqn. 5. Stover Production
- 15. Pasture Productivity Figure 2: Global grassland productivity
- 16. Ruminant Numbers Accounting Suggested: •Distinguish meat and milk herds/producers •Further disaggregate follower animals •Account for feed demand of entire herd •Impose feed availability limitations on herd expansion, esp. in mixed and extensive systems •Include in accounting of CC effects on livestock
- 17. Livestock Numbers Response • Follower numbers incorporating region-specific natural birth/herd growth rates • Price- responsiveness of cull/off-take for meat meat milk fllw t t t tN N N N where N is animal numbers; C is the animals culled for meat, g are herd-specific growth rates, ϴ is the share of animals in the meat herd that are culled in period t; Total Numbers growth 1 (1 )nmbr t t t tN N C g , ( ) 1meat t cull t cull meatC N f P Total Numbers at time t Cull/slaughter • From FAO data we observe milk animals (𝑁𝑡 𝑚𝑖𝑙𝑘 ), the animals culled (𝐶𝑡) and the total herd (𝑁𝑡) • Back-out follower numbers (𝑁𝑡 𝑓𝑙𝑙𝑤 ) and 𝑁𝑡 𝑚𝑒𝑎𝑡 that are consistent with the data
- 18. Revised Feed Demand (for marketed feeds) , , ,r b r b r bPI π = Share allocated to each marketed feed QL = Demand for marketed feed PI = The effective intermediate (feed) price diet = Dietary requirement per animal N = Total number of animals (including followers) MktFeed = Feed ratio β = Feed demand intercepts PI = The effective intermediate (feed) price b = Commodity indices specific to feed crops where: l = Commodity indices specific to livestock γ = Price elasticity of feed demand , , total r b r b rQL MktFeed , , , , , total r l sys FPU l sys FPU b mktFeeds l sys FPU MktFeed N diet Share to each marketed feed good Allocation across sum of marketed feeds The total demand for marketed feeds as a function of diets and numbers
- 19. Projections of other feed demand Simpler treatment of non-marketed feeds: • Crop grain-residue: availability increases with crop production • Pastures: fixed by given grassland area and productivity (don’t have means of modeling changes to this presently, inclu. CC-related) • Occasional feeds: held constant at base year values (change according to scenarios?) , , avail r nmf r nmfQL nonMktFeed Essentially, a strict constraint on availability
- 20. IMPACT v 3 - Specific Features Introducing simple value chain specifications Ranch Meat Processing Country Market Cows Meat products
- 21. IMPACT v 3 - Specific Features Introducing simple value chain specifications Ranch Meat Processing Country Market Cows Meat products Feed Supplies I
- 22. IMPACT v 3 - Specific Features Introducing simple value chain specifications Ranch Meat Processing Country Market Cows Meat products Feed Supplies I Global Market Feed Supplies II
- 23. Status of Migration to IMPACT v 3 • ‘Stand-alone’ module in livestock • FPU disaggregated by livestock production system – parameterized using data from GLOBIOM model • Livestock numbers and feed demand re- balanced to match FAO values • Unit/scaling issues addressed • Module tested for one country (US) and two years • Well behaved so far! • Test to extend to multiple country and years
- 24. Next Steps and Timelines • Revised completion date end of June 2015 • Case study validation in months following • Baseline and alternative scenario development in consultation with livestock biosciences, environment and policy experts • Paper on ex-ante analysis of livestock technologies by December 2015 • Climate change, policy, related modeling in 2016 • Explore feed optimization and other features …
- 25. Thank You! Questions and Discussion
- 26. Acknowledgements This work has received support from: The Bill and Melinda Gates Foundation The CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS) The CGIAR Research Program on Policies, Institutions, and Markets (PIM)
- 27. The presentation has a Creative Commons licence. You are free to re-use or distribute this work, provided credit is given to ILRI. better lives through livestock ilri.org