economic impact of heat stress
DESCRIPTION
Farm animals have well known zones of thermal comfort (ZTC). The range of ZTC is primarily dependent on the species, the physiological status of the animals, the relative humidity and velocity of ambient air, and the degree of solar radiation. Economic losses are incurred by the U.S. livestock industries because farm animals are raised in locations and/or seasons where temperature conditions venture outside the ZTC. The objective of this presentation is to provide current estimates of the economic losses sustained by major U.S. livestock industries from thermal stress and to outline future challenges as animal productivity is improved. Species (production) considered are: chicken (meat), chicken (eggs), turkey (meat), cattle (meat), cattle (milk), and pig (meat). http://www.extension.org/pages/67799/current-and-future-economic-impact-of-heat-stress-in-the-us-livestock-and-poultry-sectorsTRANSCRIPT
Economic Impact of Heat Stress
N. R. St-PierreThe Ohio State University
Copyright 2013, N. St-Pierre, The Ohio State University
Objectives
• To present a simple model for quantifying financial losses due to heat stress across all major commercial livestock industries in the U.S.,
• To peek into the future: Global warming Increase in animal productivity
Copyright 2013, N. St-Pierre, The Ohio State University
Model Overview
• Used historical weather data to quantify the multivariate distribution of temperature and relative humidity for each of the 48 lower States.
• Summarized research data to quantify the relationships between magnitude of heat stress, duration of heat stress, and expected performance across 10 livestock classes.
Copyright 2013, N. St-Pierre, The Ohio State University
Weather
• Number of reporting stations: 257• Earliest reports start between 1871 and 1932• Data include daily:
Minimum and maximum temperature (T) Minimum and maximum relative humidity (H) Rain and snow precipitation Snow cover
Copyright 2013, N. St-Pierre, The Ohio State University
Weather
• Data were summarized by State and by month: Mean, variance and covariances of:
o Minimum temperature (Tl)
o Maximum temperature Tu)
o Minimum relative humidity (Hl)
o Maximum relative humidity (Hu)
Copyright 2013, N. St-Pierre, The Ohio State University
Weather
• Within day changes in T and H modeled as sine functions with simultaneity of Tl and Hu, and of Tu ans Hl.
• T and H integrated into a Temperature-Humidity Index (65% dry-bulb temperature, 35% wet-bulb temperature).
Copyright 2013, N. St-Pierre, The Ohio State University
WeatherTwo Integrative Variables
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Livestock Classes
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Economic Losses
• For each livestock class: DMI loss (economic gain) Production loss Days open loss Reproductive culling loss Mortality loss
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Economic LossesDairy Cows
• Threshold at 70o THI (e.g., 75o F, 50% H)• DMI loss = 0.0760 x (THIMax-70)2 x D• Milk loss = 0.1532 x (THIMax-70)2 x D
where D = Proportion of a day above threshold
• PR = 0.20 - 0.0009 x Heatload• DO loss = 164.5 - 184.5 PR + 29.38 PR2 - 128.75• RCullRate = 100 - 102.7(1-1.10109 EXP(10.1874 x PR)• Pmonthlydeath = 0.000855 EXP(0.00981 x Heatload)
Copyright 2013, N. St-Pierre, The Ohio State University
WeatherTwo Integrative Variables
(THIMAX – 70)2
Copyright 2013, N. St-Pierre, The Ohio State University
Economic LossesDairy Cows
• Threshold at 70o THI (e.g., 75o F, 50% H)• DMI loss = 0.0760 x (THIMax-70)2 x D• Milk loss = 0.1532 x (THIMax-70)2 x D
where D = Proportion of a day above threshold
• PR = 0.20 - 0.0009 x Heatload• DO loss = 164.5 - 184.5 PR + 29.38 PR2 - 128.75• RCullRate = 100 - 102.7(1-1.10109 EXP(10.1874 x PR)• Pmonthlydeath = 0.000855 EXP(0.00981 x Heatload)
Copyright 2013, N. St-Pierre, The Ohio State University
Unit Costs for Five Loss Categories
Copyright 2013, N. St-Pierre, The Ohio State University
Description of Cooling Systems
Minimal (Fans)
Moderate (Sprinklers)
Aggressive (Evaporative)
Beef Cows Fans +Sprinklers Evaporative
Beef Finish Fans +Sprinklers Evaporative
Dairy Calves Fans +Sprinklers Evaporative
Dairy Cows Fans +Sprinklers Evaporative
Dairy Yearlings Fans +Sprinklers Evaporative
Poultry Broilers Fans Tunnel Evaporative
Poultry Layers Fans Tunnel Evaporative
Poultry Turkey Fans Tunnel Evaporative
Swine Feeders Fans +Sprinklers Cool Cells
Swine Sows Fans +Sprinklers Cool Cells
Copyright 2013, N. St-Pierre, The Ohio State University
Reduction in THI from Fan Cooling
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Reduction in THI from Sprinkler Cooling
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Reduction in THI from Evaporative Cooling
Copyright 2013, N. St-Pierre, The Ohio State University
Cooling Costs
• Capital Cost 10 year depreciation 8% interest 2-5%/year for maintenance
• Operating Cost $0.09/kWh $0.01/h per unit for water 0.65 kW/h for fans (92 cm), 2.55 kW/h for
evaporative cooling
Copyright 2013, N. St-Pierre, The Ohio State University
Average Minimum Temperature - July
71.7
72.1
68.2
67.1
69.8
53.6
51.4
59.0
60.6
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Average Maximum Temperature - July
94.8
100.1
77.4
80.8
92.592.5
90.9
91.2
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Average Minimum Relative Humidity - July
56
22
14
6684
55
40
68
58
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Average Maximum Relative Humidity - July
94
74
47
94
81
8289
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Average Minimum THI - July
68.9
65.3
51.6
60.7
72.6
58.3
66.2
65.8
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Average Maximum THI - July
86.0
81.5
76.2
75.2
81.1
73.7
81.1
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91.6
Milk Production Losses - Dairy CowsNo Cooling - JULY
12351086
90
251
194
Loss in lbs/month Copyright 2013, N. St-Pierre, The Ohio State University
Gain Losses - Poultry BroilersNo Cooling - JULY
18.3
Loss in lbs/month per 1000 birds
7.5
3.1
1.3
12.1
12.8
Total Cost per Animal - Dairy CowsMinimum Cooling - Annual Basis
1356
213
112140
1310
Copyright 2013, N. St-Pierre, The Ohio State University
Total Cost - Dairy CowsMinimum Cooling- Annual Basis, in million $
199
Cost in million $Cost in million $
137
47
2053
69
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Total Cost - Dairy CowsSprinklers - Annual Basis, in million $
34
47
199
104
35 12
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Optimal System - Dairy Calves No Cooling Fans Sprinklers Evaporative Cooling
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Optimal System - Dairy Cows No Cooling Fans Sprinklers Evaporative Cooling
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Optimal System - Poultry Layers No Cooling Fans Tunnel Evaporative Cooling
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Optimal System - Poultry Turkeys No Cooling Fans Tunnel Evaporative Cooling
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Optimal System - Swine Sows No Cooling Fans Sprinklers Evaporative Cooling
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Optimal System - Swine Feeder Pigs No Cooling Fans Sprinklers Evaporative Cooling
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Economic Efficiency of Heat Abatement SystemsCost of Optimal System Cost of No Cooling
0.46
0.71
0.75
0.62
0.61
0.73
0.870.87
0.900.79
0.86
0.82 0.73
0.770.69
0.64
0.710.91
0.67
0.59 0.79
0.74
0.70
0.610.66
0.75 0.62
0.64
0.72
0.65
0.630.67
0.650.760.71
0.79
0.590.52
0.75
Copyright 2013, N. St-Pierre, The Ohio State University
TX MO NE OK SD
Optimal System None None None None NoneDMI Loss 0 0 0 0 0
Gain Loss 0 0 0 0 0
DO Loss 15.5 2.2 1.5 3.6 1.0
Repro Cull Loss 0 0 0 0 0
Death Loss 17.7 2.9 2.0 4.4 1.3
Capital Cost 0 0 0 0 0
Operating Cost 0 0 0 0 0
Total Cost 33.2 5.1 3.4 8.0 2.2
Beef CowsEconomic Losses (Million $)Five Largest Producing States
Copyright 2013, N. St-Pierre, The Ohio State University
TX KS NE CO OK
Optimal System None None None None NoneDMI Loss (34.8) (12.2) (10.8) (1.9) (3.8)
Gain Loss 162.0 57.1 50.5 8.9 17.6
DO Loss 0 0 0 0 0
Repro Cull Loss 0 0 0 0 0
Death Loss 19.0 5.0 4.5 0.6 1.9
Capital Cost 0 0 0 0 0
Operating Cost 0 0 0 0 0
Total Cost 146.6 49.8 44.2 7.6 15.7
Beef FinishEconomic Losses (Million $)Five Largest Producing States
Copyright 2013, N. St-Pierre, The Ohio State University
CA WI NY PA MN
Optimal System Sprinkler Sprinkler Sprinkler Sprinkler Sprinkler
DMI Loss (31.6) (10.8) (3.6) (10.0) (6.2)
Gain Loss 103.2 35.3 11.6 32.7 20.4
DO Loss 23.3 11.4 4.5 8.9 5.7
Repro Cull Loss 7.4 3.2 1.2 2.8 1.7
Death Loss 2.3 1.0 0.4 0.9 0.5
Capital Cost 13.7 11.6 5.9 5.3 4.6
Operating Cost 18.3 11.6 5.4 7.3 4.8
Total Cost 136.6 63.3 25.4 47.9 31.5
Dairy CowsEconomic Losses (Million $)
Five Largest Producing States (2002)
Copyright 2013, N. St-Pierre, The Ohio State University
NC IA MN IL MO
Optimal System Sprinkler Sprinkler None Sprinkler Sprinkler
DMI Loss 0 0 0 0 0
Gain Loss 0 0 0 0 0
DO Loss 10.2 6.8 4.0 3.5 5.3
Repro Cull Loss 0 0 0 0 0
Death Loss 0.1 0.1 0 0 0.1
Capital Cost 3.7 3.2 0 1.4 1.2
Operating Cost 5.4 3.3 0 1.7 2.0
Total Cost 19.3 13.4 4.1 6.7 8.5
Swine SowsEconomic Losses (Million $)Five Largest Producing States
Copyright 2013, N. St-Pierre, The Ohio State University
NC IA MN IL MO
Optimal System None None None None NoneDMI Loss (12.0) (7.5) (2.2) (3.9) (4.9)
Gain Loss 54.0 33.8 10.0 17.4 22.1
DO Loss 0 0 0 0 0
Repro Cull Loss 0 0 0 0 0
Death Loss 0.9 0.5 0.1 0.3 0.4
Capital Cost 0 0 0 0 0
Operating Cost 0 0 0 0 0
Total Cost 42.9 26.8 7.9 13.8 17.6
Swine FeederEconomic Losses (Million $)Five Largest Producing States
Copyright 2013, N. St-Pierre, The Ohio State University
Total Cost of Heat Stressto U.S. Livestock Industries
W/o Heat Abatement Systems: 2.7 billion $/yr
W Optimal Systems: 1.9 billion $/yr
Copyright 2013, N. St-Pierre, The Ohio State University
Impact of Climate Change on Future Costs
An honest discussion on the difficulties
of forecasting weather and temperatures
Copyright 2013, N. St-Pierre, The Ohio State University
Temperature Forecasting Issues
• IPCC forecasts failed to abide by seventy-two of eighty-nine forecasting principles1: Agreement among forecasters is not related to
accuracy The complexity of the global warming problem
make’s forecasting a fool’s errand – The more complex you make the model the worse the forecast gets.
The forecasts do not adequately account for the uncertainty intrinsic to the global warming problem.
Kester C. Green and J. Scott Armstrong. 2007. Global warming: Forecast by scientists verses scientific forecasts. Energy and the Environment 18:718.
Copyright 2013, N. St-Pierre, The Ohio State University
Temperature Forecasting Issues
“You cannot assume that a model with millions
and millions lines of code, literally millions
of instructions, that there isn’t a mistake in there”
K. Emmanuel, M.I.T.
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Predictions and Forecasts
Data driven predictions can succeed – and they can fail. It is when we deny our role in the process that the odds of failure rises.
Copyright 2013, N. St-Pierre, The Ohio State University
Nate Silver.
Predictions and Forecasts
We have a prediction problem. We love to predict things – and we aren’t very good at it.
Nate Silver.
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I am a DENIER!
Copyright 2013, N. St-Pierre, The Ohio State University
I am a DENIER!
I can live with doubt and uncertainty and not knowing. I think it is much more interesting to live not knowing than to have answers which might be wrong.
Richard P. Feynman
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The Essence of Science
When a scientist doesn’t know the answer to a problem, he is ignorant. When he has a hunch as to what the result is, he is uncertain. And when he is pretty darn sure of what the result is going to be, he is in some doubt.
Richard P. Feynman
Copyright 2013, N. St-Pierre, The Ohio State University
A responsibility
If we suppress all discussion, all criticism, saying, “This is it boys!”… and thus we doom man for a long time to the chains of authority, confined to the limits of our present imagination.
Richard P. Feynman
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A Principled Scientist
It’s a kind of scientific integrity, a principle of scientific thought that corresponds to a kind of utterly honesty – a kind of leaning over backwards.
Richard P. Feynman
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U.S. Temperature Data
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U.S. Temperature Data
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Trends in Hurricane Intensity
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Trends in Hurricane Intensity
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Great Lakes Ice Coverage
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Great Lakes Ice Coverage
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Arctic Ice Extent in September
Arctic Ice Extent in September
Arctic Ice Extent in September
Oceans Acidification
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Pteropods
Seawater with pH and carbonate projected for the year 2100
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Oceans Acidification
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Pteropods
Seawater with pH and carbonate projected for the year 2100
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Predictions and Forecasts
The conditions of the universe are knowable only with some degree of certainty.
Copyright 2013, N. St-Pierre, The Ohio State University
Predictions and Forecasts
Two strikes in weather forecasting:• The systems are dynamic
The behavior of the system at one point in time influences its behavior in the future.
• The systems are nonlinear They abide by exponential rather than additive
relationships.
Copyright 2013, N. St-Pierre, The Ohio State University
Climate Forecasts
• How much uncertainty is in the forecast?• How right or wrong have the predictions been so
far?• How much have politics and other perverse
incentives undermined the search for scientific proof?
Healthy skepticism toward climate predictions!
Copyright 2013, N. St-Pierre, The Ohio State University
How Cows Dissipate Heat
• Conduction• Convection• Radiation• Evaporative cooling
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Flow of Energy (Mcal/day)
40 lbs 120 lbs
Gross Energy 73.4 135.7
Feces 25.7 40.7
Digestible Energy 47.7 95.0
Urine 5.6 11.0
Gas 3.4 6.1
Metabolizable Energy 39.0 77.9
Heat 26.2 39.5
Milk Energy 12.8 38.4
Copyright 2013, N. St-Pierre, The Ohio State University
A Simplified Cow...
Ta Te
Eg
>
Ed
The cow The environment
kd
kd α Δ T
Δ T
Copyright 2013, N. St-Pierre, The Ohio State University
Increased Productivity vs. Global Warming
• The current IPCC forecasts predict that the temperatures might increase by 1.2 °F by 2050.
• Dairy productivity has increased at a rate of 318 lbs/cow per year since 1980.
Copyright 2013, N. St-Pierre, The Ohio State University
Increased Productivity vs. Global Warming
• Current animal productivity averages ~ 70 lbs/cow per day nationally. Results in 30.1 Mcal/cow per day in heat energy.
• Assuming that improvement in productivity will be maintained at 300 lbs/cow per year, the average U.S. dairy will be producing 102 lbs/cow per day in 2050 Results in 35.7 Mcal/cow per day in heat energy
• The projected improvement in potential productivity will lower the THI-threshold from 70 to 64.
Copyright 2013, N. St-Pierre, The Ohio State University
Increased Productivity vs. Global Warming
• The current IPCC forecasts predict that the temperatures might increase by 1.2 °F by 2050.
• The increased projected productivity has a net “warming effect” equivalent to 6 °F by 2050.
Increased potential productivity will have about 5 times more impact on heat stress in dairy cattle than global warming.
Copyright 2013, N. St-Pierre, The Ohio State University
The Real Issue
• Current cooling systems are not very energy efficient and they all rely on significant amounts of water being used.
Copyright 2013, N. St-Pierre, The Ohio State University
The Real Issue
• Current cooling systems are not very energy efficient and they all rely on significant amounts of water. Will energy costs outpace our ability to cool animals? Will water availability restrict our ability to cool
animals?
Copyright 2013, N. St-Pierre, The Ohio State University
Closing Comments
Copyright 2013, N. St-Pierre, The Ohio State University
The End