J.A. Lory 1, R.E. Massey 2 and M.C. Shannon 3 1 Plant Sciences, 2 Agricultural and Applied Economics, 3 Animal Science University of Missouri, Columbia MO 65211
Software is commonly used to optimize diets based on nutritional needs of the animal while identifying low-cost formulation of available ingredients. Feed optimization programs only consider input costs for evaluating low-cost rations. National Swine Nutrition Guide (NSNG) Diet Formulation and Evaluation Software (NSNG, 2010) estimates manure fertilizer value of different diets Does not include manure value as part of the optimization routine. Diet recommendations Available P was reduced in 2007 for 50-130 lb pigs; constant, otherwise. Ca was reduced in 2007 for all diets affects Ca:P ratios that can affect P in the manure. Amino Acid changed (some increased, some decreased) in 2007 can affect N in manure by affecting crude protein in diet.
Regulatory and voluntary strategy to minimize impact of manure management on water quality is to fully utilize manure nutrients as fertilizer for crop production(usepa, 2008). Fertilizer nutrients can be a significant component of net income on swine operations (e.g. Lory et al., 2004). Fertilizer value of nutrients excreted by pigs can vary widely due to many factors including: diet, manure handling system, method of application and soil nutrient status.
Cost ($/ton) 600 Corn Soybean Meal (47.5%) DDG 500 400 300 200 100 0 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012
Cost ($/ton) $1,200.00 MonoCal (21%P) DiCal (18.5%P) Anhy Ammon DAP Potash $1,000.00 $800.00 $600.00 $400.00 $200.00 $0.00 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011
Assess the impact of incorporating manure into feed management decisions. How have changes in low-cost diets over the period from 2002 to 2011 affected estimated fertilizer value of manure? Period covers the widespread adoption of incorporating corn dried distillers grains with solubles (DDG) into swine diets. Determine how low-cost diets would have changed if fertilizer value of excreted was integrated as a c0-product into linear programming feed optimization routines. The goal is no longer least cost ration formulation but jointly considering ration cost and manure value.
Evaluated four diets: grower-1 (23-35 kg pigs) and finish-2 (91-113 kg pigs) diets, with or without DDG as a feed component option. Diet composition constraints based on Kansas State University Swine Nutrition Guide (1998; 2007). In DDG diets maximum constraint was 40% inclusion for grower-1 and 30% for finish-2. Feed component composition based on NSNG (2010). Feed costs for corn, soybean meal (SBM) and distillers grains with solubles (DDG) based on USDA Annual Prices Summary (2001-2011). Prices for minerals and phytase based on production records from the Missouri Swine Feed Group (personal communication). Fertilizer value of N, P and K based on USDA Annual Prices Summary (2001-2011). Nutrient retention (N, P, K) of pigs based on equations in NSNG (2010). Nutrient availability for crop production of excreted nutrients based on slurry tank manure injected into soil. Excreted N, P and K were assumed to be 70%, 100% and100% available, respectively. Phytase effectiveness based on Naturophos option in NSNG (2010). Linear programming optimization routines executed in Microsoft Excel Solver.
Key assumptions: Excreted nutrients are the difference between fed nutrient and retained nutrients. Over feeding nutrients in swine diets does not further increase nutrient retention of pigs(e.g. Henley et al., 2012;McDonnell et al., 2011). Curvilinear relationship between phytase units (FTU kg -1 ) and P availability (%) linearized for optimization routine by transforming relationships into six linear segments with decreasing effectiveness. Farmers received full fertilizer value for plant-available manure N, P and K.
Results
Cost ($/ton) 50-70 lb phase 170-210 lb phase $350.00 No DDG 40% DDG $350.00 No DDG 30% DDG $300.00 $300.00 $250.00 $250.00 $200.00 $200.00 $150.00 $150.00 $100.00 $100.00 $50.00 $50.00 $0.00 $0.00
lb. N/ton feed) 50-70 lb phase 210-250 lb phase 45 No DDG 40% DDG 45 No DDG 30% DDG 40 40 35 35 30 30 25 25 20 20 15 1997 Constraints 2007 Constraints 15 1997 Constraints 2007 Constraints 10 10 5 5 0 0
lb. P2O5/ton feed) 50-70 lb phase 210-250 lb phase 25 No DDG 40% DDG 25 No DDG 30% DDG 20 20 15 15 10 1997 Constraints 2007 Constraints 10 1997 Constraints 2007 Constraints 5 5 0 0
lb. K2O/ton feed) 50-70 lb phase 210-250 lb phase 25 No DDG 40% DDG 25 No DDG 30% DDG 20 20 15 15 10 1997 Constraints 2007 Constraints 10 1997 Constraints 2007 Constraints 5 5 0 0
lb. P/ton feed) No DDG in diet 40% DDG in diet 14 Corn P SBM P DDG P Mineral P 14 Corn P SBM P DDG P Mineral P 12 12 10 10 8 8 6 1997 Constraints 2007 Constraints 6 4 4 1997 Constraints 2007 Constraints 2 2 0 0
Value ($/ton of feed) 50-70 lb No DDG 50-70 lb 40% DDG 210-250 lb No DDG 210-250 lb 30% DDG 45.00 40.00 35.00 30.00 25.00 20.00 15.00 10.00 5.00 0.00 2003 2004 2005 2006 2007 2008 2009 2010 2011
Percent 50-70 lb No DDG 50-70 lb 40% DDG 210-250 lb No DDG 210-250 lb 30% DDG 25% 20% 15% 10% 5% 0% 2003 2004 2005 2006 2007 2008 2009 2010 2011
Costs: $184.04 /hog (58% feed) Loss: $ 12.47 /hog Manure 1 : $ 8.41 /hog Feed, $107.18 Variable Costs, $22.19 Operating Interest, $3.32 Fixed Costs, $8.45 Feeder Pig, $38.55 1 ISU analysis did not include manure value.
Profit/Loss ($/pig) 40.00 30.00 20.00 Includes Full Manure Value No Manure Value 10.00 0.00-10.00 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012-20.00-30.00-40.00
DDG always the low-cost diet. DDG always increased diet CP and excreted N. In Grower diets, DDG diet is the low-p diet. In Finish diets, Corn-SBM diets is the low-p diet. Differences are small. There are fewer manure nutrients due to diet changes over time; but increasing fertilizer costs have made manure nutrients more valuable.
Results
lb. P/ton feed) 12 Manure value not in optimization Corn P SBM P DDG P MonoCal P DiCal P 14 14 12 Manure value in optimization Corn P SBM P DDG P MonoCal P Dical P 10 10 8 8 6 4 1997 Constraints 2007 Constraints 6 4 1997 Constraints 2007 Constraints 2 2 0 0
Change ($ Mg -1 ) Year Diet Cost Manure Value Net Value 2007 1.91 2.45 0.54 2008 0.00 0.00 0.00 2009 0.00 0.00 0.00 2010 0.35 0.38 0.04 2011 1.03 1.20 0.17
lb. P/ton feed) Corn P SBM P DDG P MonoCal P DiCal P 10 9 8 Manure value not in optimization 10 9 8 Manure value in optimization Corn P SBM P DDG P MonoCal P Dical P 7 6 7 6 5 1997 Constraints 2007 Constraints 5 4 3 2 1 0 4 3 2 1 0 1997 Constraints 2007 Constraints
Change ($ ton feed) Year Diet Cost Manure Value Net Value 2007 0.06 0.08 0.02 2008 0.11 0.26 0.15 2009 0.03 1.54 1.50 2010 0.57 1.43 0.86 2011 0.75 1.69 0.94
Mean Benefit Max Benefit - - - $ Mg -1 - - - Grower-1 w/o DDG -0.92-2.02 Grower-1 w/ddg -0.69-1.19 Finish-1 w/o DDG -0.39-0.66 Finish-2 w/ddg -0.35-0.50
Net Feed Cost Difference between Manure included and Manure not included in optimization Net Feed Cost = Feed Cost Manure Value 210-250 170-210 130-170 DDG No DDG 90-130 70-90 50-70 $0.00 $0.20 $0.40 $0.60 $0.80 $1.00
1. Had no effect on diet composition 2001-2006. 2. Small benefits but worth evaluating in 2007-2011. 3. Eliminated phytase from diets containing DDG. 4. Reduced or eliminated phytase in C-SBM diets. Controlled by energy in diet and P- density of P sources.
Manure is a significant source of value to livestock producers. Opportunities exist to integrate the value of manure into the least cost diet decision so that net income is optimized. Impact is currently small. Caveat: cost of diets are certain expense; value of manure is uncertain revenue. Minimizing P Excretion in C-SBM diets still limited by P availability of corn.