Avg Productive Life of Sows=
	36
	~	months
	~		|

Breeding Rate=
	Breeding Stock*Litters per Pig Month*Pigs Saved per Litter
	~	pigs/Month
	~		|

Breeding Stock= INTEG (
	Breeding Stock Adjustment Rate-Old Sow Slaughter Rate,
		8.2e+006)
	~	pigs
	~		|

Breeding Stock Adjustment Delay=
	5
	~	months
	~		|

Breeding Stock Adjustment Rate=
	(Desired Breeding Stock-Breeding Stock)/Breeding Stock Adjustment Delay
	~	pigs/Month
	~		|

Breeding Stock Sow Fraction=
	0.6
	~	fraction
	~		|

Consumer Population=
	2e+008
	~	people
	~		|

Consumption Rate=
	Consumer Population*Per Capita Pork Consumption
	*(1+Test Input)
	/(Hog Dressed Yield*Live Weight of Slaughtered Hogs)
	~	pigs/Month
	~		|

Desired Breeding Stock=
	Desired Breeding Stock Lookup(Expected Hog Corn Ratio)
	~	pigs
	~		|

Desired Breeding Stock Lookup(
	[(0,0)-(40,2e+007)],(10,5e+006),(15,7e+006),(20,9e+006),(25,1.1e+007))
	~	pigs
	~		|

Desired Inventory Coverage=
	0.36
	~	Month
	~		|

Effective Inventory=
	Inventory*Hog Dressed Yield*Live Weight of Slaughtered Hogs
	~	lb
	~		|

Expected Consumption Rate=
	1e+009
	~	lb/Month
	~		|

Expected Corn Price=
	1
	~	$/unit
	~		|

Expected Hog Corn Ratio=
	Expected Hog Price/Expected Corn Price
	~	($/pig)/($/unit)
	~		|

Expected Hog Price= INTEG (
	Expected Hog Price Adj Rate,
		21.2)
	~	$/pig
	~		|

Expected Hog Price Adj Rate=
	(Live Hog Price-Expected Hog Price)/Hog Price Expectation Adj Time
	~	($/pig)/Month
	~		|

"Gestation & Maturation Delay"=
	10
	~	months
	~		|

Hog Dressed Yield=
	0.58
	~	fraction
	~		|

Hog Price Expectation Adj Time=
	6
	~	months
	~		|

Inventory= INTEG (
	+Mature Stock Slaughter Rate+Old Sow Slaughter Rate-Consumption Rate,
		2e+008/(Live Weight of Slaughtered Hogs*Hog Dressed Yield))
	~	pigs
	~		|

Inventory Coverage=
	Effective Inventory/Expected Consumption Rate
	~	months
	~		|

Litters per Pig Month=
	0.17
	~	litters/pig/Month
	~		|

Live Hog Price=
	Live Hog Price Lookup(Relative Inventory Coverage)
	~	$/pig
	~		|

Live Hog Price Lookup(
	[(0,0)-(2,40)],(0,35),(0.25,26.5),(0.5,21.7),(0.75,18.7),(1,16.5),(1.25,13),(1.5,9.5\
		),(1.75,5.5),(2,0))
	~	$/hog
	~		|

Live Weight of Slaughtered Hogs=
	240
	~	lb/pig
	~		|

Market Margin=
	28
	~	$/pig
	~		|

Maturation Rate=
	DELAY3( Breeding Rate*Weaning Survival Factor , "Gestation & Maturation Delay" )
	~	pigs/Month
	~		|

Mature Stock= INTEG (
	+Maturation Rate-Breeding Stock Adjustment Rate-Mature Stock Slaughter Rate,
		1.3e+007)
	~	pigs
	~		|

Mature Stock Feeding Period=
	2
	~	months
	~		|

Mature Stock Slaughter Rate=
	Mature Stock/Mature Stock Feeding Period
	~	pigs/Month
	~		|

Noise=
	0
	~	dmnl
	~		|

Old Sow Slaughter Rate=
	Breeding Stock*Breeding Stock Sow Fraction/Avg Productive Life of Sows
	~	pigs/Month
	~		|

Per Capita Pork Consumption=
	Per Capita Pork Consumption Lookup(Retail Price)
	~	lb/person/Month
	~		|

Per Capita Pork Consumption Lookup(
	[(0,0)-(100,10)],(40,6.4),(60,5),(80,3.7))
	~	lb/person/Month
	~		|

Pigs Saved per Litter=
	7
	~	pigs/litter
	~		|

Relative Inventory Coverage=
	Inventory Coverage/Desired Inventory Coverage
	~	dmnl
	~		|

Retail Price=
	Live Hog Price/Hog Dressed Yield+Market Margin
	~	$/pig
	~		|

Test Input=
	STEP(0.15,0)+STEP(-0.15,10)+Noise
	~	dmnl
	~		|

Weaning Survival Factor=
	0.7
	~	fraction
	~		|

********************************************************
	.Control
********************************************************~
		Simulation Control Paramaters
	|

FINAL TIME  = 150
	~	Month
	~	The final time for the simulation.
	|

INITIAL TIME  = 0
	~	Month
	~	The initial time for the simulation.
	|

SAVEPER  = 
        TIME STEP
	~	Month
	~	The frequency with which output is stored.
	|

TIME STEP  = 0.5
	~	Month
	~	The time step for the simulation.
	|

\\\---/// Sketch information - do not modify anything except names
V300  Do not put anything below this section - it will be ignored
*View 1
$0,0,Times New Roman|12||0-0-0|0-0-0|0-0-0|-1--1--1|-1--1--1
10,1,Mature Stock,297,166,40,20,3,3,0,0,0,0,0,0
10,2,Breeding Stock,438,299,40,20,3,3,0,0,0,0,0,0
10,3,Inventory,577,166,40,20,3,3,0,0,0,0,0,0
1,4,6,3,4,0,0,22,0,0,0,-1--1--1,,1|(490,166)|
1,5,6,1,100,0,0,22,0,0,0,-1--1--1,,1|(384,166)|
11,6,604,437,166,6,8,34,3,0,0,1,0,0,0
10,7,Mature Stock Slaughter Rate,437,185,90,11,32,3,0,0,-1,0,0,0
12,8,48,788,166,8,8,0,3,0,0,-1,0,0,0
1,9,11,8,4,0,0,22,0,0,0,-1--1--1,,1|(742,166)|
1,10,11,3,100,0,0,22,0,0,0,-1--1--1,,1|(654,166)|
11,11,48,698,166,6,8,34,3,0,0,1,0,0,0
10,12,Consumption Rate,698,185,58,11,32,3,0,0,-1,0,0,0
1,13,15,3,4,0,0,22,0,0,0,-1--1--1,,1|(578,238)|
1,14,15,2,100,0,0,22,0,0,0,-1--1--1,,1|(525,299)|
11,15,460,578,299,6,8,34,3,0,0,1,0,0,0
10,16,Old Sow Slaughter Rate,578,318,76,11,32,3,0,0,-1,0,0,0
1,17,19,2,4,0,0,22,0,0,0,-1--1--1,,1|(351,299)|
1,18,19,1,100,0,0,22,0,0,0,-1--1--1,,1|(298,238)|
11,19,348,298,299,6,8,34,3,0,0,1,0,0,0
10,20,Breeding Stock Adjustment Rate,298,318,102,11,32,3,0,0,-1,0,0,0
12,21,48,110,170,8,8,0,3,0,0,-1,0,0,0
10,22,Weaning Survival Factor,129,107,77,11,0,3,0,0,0,0,0,0
10,23,"Gestation & Maturation Delay",239,77,93,11,0,3,0,0,0,0,0,0
1,24,1,7,1,0,0,0,0,64,0,-1--1--1,,1|(357,215)|
10,25,Mature Stock Feeding Period,429,97,92,11,0,3,0,0,0,0,0,0
1,26,25,6,0,0,0,0,0,64,0,-1--1--1,,1|(432,126)|
10,27,Litters per Pig Month,-121,289,67,11,0,3,0,0,0,0,0,0
10,28,Pigs Saved per Litter,-35,325,66,11,0,3,0,0,0,0,0,0
10,29,Breeding Stock Adjustment Delay,170,270,105,11,0,3,0,0,0,0,0,0
1,30,2,20,1,0,0,0,0,64,0,-1--1--1,,1|(337,340)|
1,31,29,20,0,0,0,0,0,64,0,-1--1--1,,1|(226,291)|
1,32,2,16,1,0,0,0,0,64,0,-1--1--1,,1|(505,341)|
10,33,Breeding Stock Sow Fraction,500,390,92,11,0,3,0,0,0,0,0,0
10,34,Avg Productive Life of Sows,610,420,90,11,0,3,0,0,0,0,0,0
1,35,33,16,0,0,0,0,0,64,0,-1--1--1,,1|(533,358)|
1,36,34,16,0,0,0,0,0,64,0,-1--1--1,,1|(596,375)|
10,37,Desired Breeding Stock,240,440,75,11,0,3,0,0,0,0,0,0
10,38,Expected Hog Corn Ratio,280,520,81,11,0,3,0,0,0,0,0,0
10,39,Expected Corn Price,170,590,66,11,0,3,0,0,0,0,0,0
1,40,39,38,0,0,0,0,0,64,0,-1--1--1,,1|(218,558)|
1,41,38,37,1,0,0,0,0,64,0,-1--1--1,,1|(253,485)|
1,42,37,20,1,0,0,0,0,64,0,-1--1--1,,1|(254,377)|
10,43,Expected Hog Price,370,570,40,20,3,3,0,0,0,0,0,0
12,44,48,591,565,8,8,0,3,0,0,-1,0,0,0
1,45,47,43,4,0,0,22,0,0,0,-1--1--1,,1|(457,565)|
1,46,47,44,100,0,0,22,0,0,0,-1--1--1,,1|(550,565)|
11,47,48,511,565,6,8,34,3,0,0,1,0,0,0
10,48,Expected Hog Price Adj Rate,511,584,93,11,32,3,0,0,-1,0,0,0
1,49,43,38,1,0,0,0,0,64,0,-1--1--1,,1|(297,548)|
1,50,43,48,1,0,0,0,0,64,0,-1--1--1,,1|(417,612)|
10,51,Hog Price Expectation Adj Time,420,660,101,11,0,3,0,0,0,0,0,0
1,52,51,48,1,0,0,0,0,64,0,-1--1--1,,1|(506,624)|
10,53,Effective Inventory,690,300,59,11,0,3,0,0,0,0,0,0
10,54,Live Weight of Slaughtered Hogs,730,240,65,25,8,3,0,0,0,0,0,0
10,55,Hog Dressed Yield,860,340,60,11,0,3,0,0,0,0,0,0
10,56,Inventory Coverage,740,350,62,11,0,3,0,0,0,0,0,0
10,57,Expected Consumption Rate,820,410,45,25,8,3,0,0,0,0,0,0
10,58,Relative Inventory Coverage,750,460,88,11,0,3,0,0,0,0,0,0
10,59,Desired Inventory Coverage,800,530,88,11,0,3,0,0,0,0,0,0
10,60,Live Hog Price,610,530,48,11,0,3,0,0,0,0,0,0
1,61,60,47,0,0,0,0,0,64,0,-1--1--1,,1|(554,549)|
1,62,59,58,0,0,0,0,0,64,0,-1--1--1,,1|(779,500)|
1,63,56,58,1,0,0,0,0,64,0,-1--1--1,,1|(751,396)|
1,64,58,60,1,0,0,0,0,64,0,-1--1--1,,1|(698,496)|
1,65,57,56,0,0,0,0,0,64,0,-1--1--1,,1|(776,377)|
1,66,53,56,1,0,0,0,0,64,0,-1--1--1,,1|(721,327)|
10,67,Retail Price,890,580,37,11,0,3,0,0,0,0,0,0
10,68,Market Margin,850,650,48,11,0,3,0,0,0,0,0,0
1,69,60,67,1,0,0,0,0,64,0,-1--1--1,,1|(725,581)|
1,70,68,67,0,0,0,0,0,64,0,-1--1--1,,1|(866,621)|
10,71,Per Capita Pork Consumption,980,370,94,11,0,3,0,0,0,0,0,0
1,72,67,71,1,0,0,0,0,64,0,-1--1--1,,1|(962,490)|
1,73,71,12,1,0,0,0,0,64,0,-1--1--1,,1|(897,261)|
1,74,3,53,1,0,0,0,0,64,0,-1--1--1,,1|(627,246)|
1,75,54,53,0,0,0,0,0,64,0,-1--1--1,,1|(709,271)|
1,76,55,53,1,0,0,0,0,64,0,-1--1--1,,1|(797,311)|
1,77,54,12,1,0,0,0,0,64,0,-1--1--1,,1|(723,225)|
10,78,Consumer Population,949,197,67,11,0,3,0,0,0,0,0,0
10,79,Test Input,879,137,33,11,0,3,0,0,0,0,0,0
10,80,Noise,889,77,20,11,0,3,0,0,0,0,0,0
1,81,80,79,1,0,0,0,0,64,0,-1--1--1,,1|(892,104)|
1,82,79,12,1,0,0,0,0,64,0,-1--1--1,,1|(822,168)|
1,83,78,12,0,0,0,0,0,64,0,-1--1--1,,1|(825,190)|
1,84,55,12,1,0,0,0,0,0,0,-1--1--1,,1|(823,257)|
1,85,55,67,1,0,0,0,0,0,0,-1--1--1,,1|(897,459)|
10,86,Maturation Rate,297,185,60,11,0,2,1,3,-1,0,0,0,128-128-128,0-0-0,|12||128-128-128
1,87,93,1,4,0,0,22,0,0,0,-1--1--1,,1|(225,170)|
1,88,93,21,100,0,0,22,0,0,0,-1--1--1,,1|(149,170)|
10,89,Breeding Rate,9,239,45,11,0,3,0,0,-1,0,0,0
1,90,89,94,1,0,0,0,0,1,0,-1--1--1,,1|(76,198)|
1,91,23,93,0,0,0,0,0,0,0,-1--1--1,,1|(214,119)|
1,92,22,93,0,0,0,0,0,0,0,-1--1--1,,1|(155,136)|
11,93,236,187,170,6,8,34,3,0,0,1,0,0,0
10,94,Maturation Rate,187,189,51,11,32,3,0,0,-1,0,0,0
1,95,2,89,1,0,0,0,0,0,0,-1--1--1,,1|(235,400)|
1,96,27,89,0,0,0,0,0,0,0,-1--1--1,,1|(-62,266)|
1,97,28,89,0,0,0,0,0,0,0,-1--1--1,,1|(-16,288)|
10,98,Desired Breeding Stock Lookup,130,490,101,11,0,3,0,0,-1,0,0,0
1,99,98,37,0,0,0,0,0,0,0,-1--1--1,,1|(178,467)|
10,100,Live Hog Price Lookup,540,480,74,11,0,3,0,0,-1,0,0,0
1,101,100,60,0,0,0,0,0,0,0,-1--1--1,,1|(568,500)|
10,102,Per Capita Pork Consumption Lookup,1080,450,55,30,8,3,0,0,-1,0,0,0
1,103,102,71,0,0,0,0,0,0,0,-1--1--1,,1|(1023,404)|
12,104,0,510,20,429,11,0,4,0,2,-1,0,0,0,0-0-0,0-0-0,|0||0-0-255
Replicated by Ed Anderson and Liz Krahmer from: Meadows, D. L. (1970). Dynamics of Commodity Production Cycles. Productivity Press.
12,105,0,510,50,200,11,0,4,0,2,-1,0,0,0,0-0-0,0-0-0,|0||0-0-255
Translated to Vensim by Tom Fiddaman, Ventana Systems, 1998
///---\\\
:GRAPH INVENTORY_PHASE
:TITLE Inventory Phase
:X-AXIS Inventory
:X-DIV 2
:Y-DIV 2
:SCALE
:VAR Breeding Stock
:VAR Mature Stock
:SCALE
:VAR Expected Hog Price
:L<%^E!@
9:Current
22:$,Dollar,Dollars,$s
22:Day,Days
22:Hour,Hours
22:litter,litters
22:Month,Months
22:Person,People,Persons
22:pig,pigs,hog,hogs
22:Unit,Units
22:Week,Weeks
22:Year,Years
15:0,0,0,0
19:75,0
4:Time
5:Per Capita Pork Consumption Lookup