cooling poultry

8/11/2019 Cooling Poultry

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Cooling Poultry inCooling Poultry inTropical ClimatesTropical ClimatesHongwei Xin, Professor

Director of Egg Industry Center Iowa State University

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OutlineOutlineBrief overview of U.S. poultry production systemsPoultry responses to thermal environment

Poultry cooling options in tropical climatesPad-fan cooling with tunnel ventilation

High-pressure fogging

Low-pressure sprinkling


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Typically 20,000 - 30,000birds, 0.75 ~ 0.9 ft 2/bird(12~14 birds/m 2)

New bedding or build-up litter

Growth period: 6 8 wks Brooders + space heaters

Evaporative cooling pads,high-pressure fogging, or low-pressure sprinkling

Natural or tunnel ventilation

Broiler HousesBroiler Houses


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10,000 - 15,000 birds New or build-up litter

Growth period: 12 wk (hen) 20 wk (tom)

Natural or mechanical vent

Turkey HousesTurkey Houses


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HighHigh --rise Layer Houserise Layer House Typically 80,000 125,000 hens

In-house manure storage (~1 yr) Manure scraped or direct drop


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ManureManure --Belt Layer HouseBelt Layer House

Typically 100,000 -125,000 hens per house Manure removed daily to semi-weekly;

improved indoor air quality On/off farm manure storage or composting


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Cage-free Layer House

5,000 -10,000 hens perhouse

Littered flooring, nest

boxes, perches, dust-bathing area


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Poultry Responses to

Thermal Environment


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HeatHeat --Wave DevastationWave Devastation

A scene from 1995 Heat Wave in Iowa


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Consequence of Ventilation FailureConsequence of Ventilation Failure


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Pathways of Animal Heat DissipationPathways of Animal Heat Dissipation

Respiratoryheat loss

Conductive heat loss

Convective heat loss

Air movement

Radiativeheat loss

HLcond + HL conv + HL rad = Sensible Heat Loss (SHL)


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Genetic Adaptation to Hot ClimateGenetic Adaptation to Hot Climate


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Featherless & Naked Neck ChickensFeatherless & Naked Neck Chickens

More heat tolerant!


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Environmental Factors AffectingEnvironmental Factors Affecting Animal Heat Dissipation Animal Heat Dissipation

Surrounding temperatures SHL Air (convective)

Ceiling/roof or wall (radiative)Floor (conductive)

Air Velocity SHLHumidity or vapor pressure LHL


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Combined Effects of Temperature andCombined Effects of Temperature and

Humidity on Livestock & PoultryHumidity on Livestock & PoultryTemperature-Humidity Index (THI)

THI = a Tdb + b Twb (b = 1-a)

Animal Species a b

Cattle 0.35 0.65

G-F pigs 0.65 0.35

Laying hens 0.60 0.40

Hen turkeys 0.74 0.26

Tom turkeys 0.64 0.36


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Body Temperature Rise of 2.8 kg Broilers

at Different Temp & Humidity Conditions

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

0 30 60 90 120 150 180 210 240Exposure Time (min)

B o

d y

T e m p e r a

t u r e

R i s e

( o C )

41 26.1

41 19.4 38 26.1

38 19.4

35 26.1

35 19.4


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Combined Effects of Air Temperature,Combined Effects of Air Temperature,Humidity and VelocityHumidity and Velocity

Temperature-Humidity Velocity Index (THVI)

THVI = (a Tdb + b Twb)Vc

THVI =0.85T db + 0.15T wb

V0.058

For broilers (2.8 kg):


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Homeostasis Zones of 2.8-kg Broilers

Subjected to Acute Heat Exposure

0

30

60

90

120

150

180

210

240

32 33 34 35 36 37 38 39 40 41 42 43 44

THVI ( oC)

T h e r m a

l E x p o s u r e

T i m e

( m i n )

N o r m a l

A l e r t

D a n g e r

E m e r g e n c y

CBT thresholds: 1.0 (normal), 2.5 (alert), 4.0 (danger), & > 4.0 oC (emergency)

[(0.85t db + 0.15t wb)/V0.058 ]


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Ventilation Rates for PoultryVentilation Rates for PoultryCold Mild Hot

m 3hr -1unit -1

Broilers

Turkeys

0 - 7 d head 0.07 0.34 0.68> 7 d kg 0.4 1.9 3.7

Layers kg 0.4 1.9 3.7 5.6

Poults head 0.34 1.2 1.7 6.8Growers kg 0.3 1.3 3.0

Species Unit


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Air Flow Pattern In Poultry Houses Air Flow Pattern In Poultry Houses

Air stream

Cross Ventilation

Air stream

Tunnel Ventilation


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Tunnel Ventilated Broiler HouseTunnel Ventilated Broiler House

To increase cooling effect by helping birds dissipate body heat faster

Air stream


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Effect of Air Velocity as Affected byEffect of Air Velocity as Affected byVentilation ModeVentilation Mode CrossCross vs.vs. TunnelTunnel

A broiler barn with a dimension of 12 x 121 m (40 x 400 ft)

and a drop-ceiling height of 3 m (10 ft). Determine theaverage air velocity through the house if cross or tunnelventilation is used to ventilate the barn at 170,000 m 3/hr

(100,000 CFM) air flow.Q

V = A

For cross ventilation: A = 121 x 3 = 363 m 2

V = 170,000/363 = 468 m/hr = 0.13 m/s

For tunnel ventilation: A = 12 x 3 = 36 m 2V = 170,000/36 = 4722 m/hr = 1.31 m/s

Q = 170,000 m 3/hr


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Effective Temperature vs. Air

Velocity for Broiler Chickens

606570

75

80859095

100

0 100 200 300 400 500 A ir Velo c i ty , f t /m in

E f f e c t

i v e

T e m p e r a

t u r e ,

F

A ir t em p = 90F

(1.5, 25)

0.0 0.5 1.0 1.5 2.0 2.5m/s

E f f e c t

i v e

T e m p e r a

t u r e ,

C 40

36

32

28

24

20

16

Air temp = 32 C


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Poultry Cooling Options


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Evaporative Cooling Process

Wet-bulb l ine

85% RH

15 C

18 C 30 C

Saturation Line

0.01070 kg/kg da

0.00525 kg/kg da

Dry-bulb Air Temperature

Humidity Ratio

20% RH

1

2Hi T

Lo RHLo T

Hi RH

EC Pad


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Broiler Barn with Tunnel VentilationBroiler Barn with Tunnel Ventilationand Evaporative Cooling Padsand Evaporative Cooling Pads


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Pad-Fan Evaporative Cooling

0

5

10

15

20

25

30

35

40

7/11 7/18 7/25 8/1 8/8 8/15Date, m/d

A i r T e m p e r a

t u r e , o

C

0

5

10

15

20

T e m p e r a

t u r e

R e d u c t

i o n , o C

Before_Temp After_Temp Diff


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II.II. Cooling by HighCooling by High --PressurePressure

Fogging Inlet or Inside Air Fogging Inlet or Inside Air


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Temp. Reduction by Inlet FoggingTemp. Reduction by Inlet Fogging

0

1

2

3

4

5

6

7

07/03 07/10 07/17 07/24 07/31 08/07 08/14 08/21 08/28 09/04Date of 1999 (month/day)

T o_ m a x - T i_ m a x

( o C )


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0%

10%20%30%40%50%60%70%

80%90%

100%

421-Jul

4415-Jul

4629-Jul

4812-Aug

5026-Aug

529-

Sep

5423-Sep

567-

Oct

5821-Oct

604-

Nov

6218-

Nov

Hen Age (week) and Date of 1999

H e n - d a y

E g g

P r o

d u c t

i o n

Standard at TN

Measured (fit)

Weekly Avg. HenWeekly Avg. Hen --Day Egg ProductionDay Egg Production

HDEP during 7/1 - 9/2:

Measured = 84.0 2.1%Standard = 85.8 1.3%


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III.III. Cooling Broilers byCooling Broilers by

Surface WettingSurface Wetting


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Determination of Cooling Need

Factorial combination of t db = 35, 38, & 41 oC; t dp =19 & 26 oC; V = 0.2, 0.7, & 1.2 m/s

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Body & Surface Temp Profiles of Cooledvs. Non-cooled Broilers

Thermal Condition:

38oC t db , 34% RH, and 0.7 m/s V

28

30

32

34

36

38

40

42

44

46

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0 30 60 90 120 150

Exposure Time(min)

B i r d

B o

d y a n

d S u r

f a c e

T e m p

( o C )

tb-Trt tb-Ctrl ts-Trt ts-Ctrl

Thermal Condition: 38oC t db ,

34% RH, and 0.2 m/s V

28

30

32

34

36

38

40

42

44

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0 30 60 90 120 150 180

Exposure Time (min)

B i r d

B o d y a n

d S u r

f a c e

T e m p . (

o C )

tb-Trt tb-Ctrl ts-Trt ts-Ctrl


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IV. Cooling Laying Hens byIV. Cooling Laying Hens byPartial Surface WettingPartial Surface Wetting(PSW)(PSW)


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Commercial High-Rise Layer House

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Effects of PSW on Hens (Lab Test)Effects of PSW on Hens (Lab Test)

Response Control Sprinkling

Mortality (%) 100 40

Survival time (min) 141 210 (>480)

Avg T b rise (oC) 2.9 2.8 (1.8)

Max T b

rise ( oC) 5.7 5.3 (3.7)

Lethal BHL ( oC-hr) 6.6 10.0

Numbers in parentheses are for survived birds.


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T/RH logger

Field Verification of PSWField Verification of PSW

Sprinkling: when T a>32 oC; 15 s per 15 min


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Tier LocationRegimen Top 2 nd 3 rd Bottom Overall

Sprinkle 697 a

746 c

748 c

707 a

724x

Control 660 b 726 d 739 c ,d 695 a 705 y

a, b, c, d: P


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Control Sprinkling

Top tier

2nd tier

3 rd tier

Bottom tier

EggshellIntegrity

No sign of bluedye penetration

through shell


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ClosureClosureSufficient ventilation capacity is essential tominimizing animal heat stress.

Properly utilizing available ventilation capacity isequally important to maximizing the benefits offorced ventilation.

For a given ventilation rate, tunnel ventilationyields higher air velocity and thus provides more

cooling to the animals than crosswise ventilation.


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ClosureClosurePad-and-fan, high-pressure fogging, or surfacewetting may be used to alleviate animal heat stress.

Pad-and-fan and fogging systems are effective underwarm and dry climates cool using more water.

Surface wetting is effective under warm/dry orwarm/humid conditions using less water; but maybe limited by physical configuration of the barns.


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http://www ans iastate edu/EIC

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sustained cooperativeresearch, extensionand education.

cooling poultry

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