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SowBridge

Importance of Ventilation for Pig Comfort

Steve Pohl South Dakota State University

Stephen.Pohl@sdstate.edu 2

Basic Environmental Factors & Their Effects on

Pigs

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Thermal Environment of the Pig

•  Air temperature seldom temperature pig feels –  Air speed –  Humidity –  Group size –  Building materials, design, surface temperature

(insulation) •  Effective Environmental Temperature

(EET) –  What pig really feels –  Combined influence of many factors

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Heat Exchange Between a Pig & It’s Surroundings

•  4 basic forms of heat transfer for the pig – Conduction – Convection – Radiation – Evaporation

* Understanding how a pig gains/loses heat is the key to providing the pig with the optimum environment and comfort

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Effect of air temp on rectal temp, respiration rate, & pulse rate of growing

pigs

102.3 102.2 102.6 104

125 120 120

100

2030

60

100

20

40

60

80

100

120

140

40 60 80 100

RectalPulseResp

Room Temperature (OF) 6

LCT, UCT, & TNZ

•  Lower Critical Temperature (LCT) – Consume more feed – Apply extraordinary measures to keep warm

•  Upper Critical Temperature (UCT) – Suppress feed intake – Apply extraordinary measures to stay cool

•  Thermal Neutral Zone (TNZ) – EET that optimizes production efficiency

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Thermal Neutral Zone, Upper & Lower Critical Temperatures

02468

1012141618

Mcal intakeFeed/gainADG, lbs

TNZ UCT LCT

Cold Stress Heat Stress

??? oF 75 oF

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Heat Stress and the Breeding Herd

Jun Jul Aug Sep Oct Nov Dec Jan Feb

Heat Stress

Litters affected by heat stress on sows

Reduced boar fertility

Litters affected by reduced boar fertility

Levis, 1980

Ventilation Systems Affect: n  Air temperature

n  Fluctuation n  Uniformity

n  Moisture and contaminant levels n  Dust and disease organisms n  Gas concentrations (odor, unvented

heaters)

n  Air speed across animals n  Surface conditions

n  Temperature, condensation, drying, etc. 9

Conventional, Negative-Pressure Ventilation Systems •  Exhaust fans • Air inlets • Controls

•  Total [HVAC] system • Heaters • Evaporative cooling

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Exhaust Fans

•  Select # and size for cold, mild, and hot weather

• Place so not exceeding suggested maximum spacings. • Centrally along regions of room • Away from corners of room •  In banks (groups) for ready wiring & access

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Recommended Ventilation Rates (cfm/pig)

Sow & Litter (cfm/sow) 20 80 500

Finishing 150-250# 10 35 120

Gestating Sows 12 40 150

Breeding Sows 14 50 300

Boars 14 50 300

Minimum Hot weather Mild

MWPS

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www.mwps.org to order

Or

access fan data online at:

www.bess.uiuc.edu

Choosing Fans for Your facilities

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Fan Test Data

Static pressure Speed Airflow Efficiency in. H2O rpm cfm cfm/W

0.00 520 24,600 21.4 0.05 520 22,800 19.3 0.10 520 21,000 17.5 0.15 520 18,900 15.5 0.20 520 16,100 13.4

0.25

BESS Lab 14

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Effect of Drive Belt Tension 48-inch Fan

0

5000

10000

15000

20000

25000

0 20 40 60

Static Pressure (pa)

Airfl

ow (c

fm)

BESS lab

Airflow before belt adj.

Airflow after belt adj.

Linear (Airflow beforebelt adj.)Linear (Airflow afterbelt adj.)

0.08 inches 0.16 inches

Air Inlets

• Room • Place for even air distribution • Size for capacity to meet maximum

ventilation needs •  Include ability to adjust properly

• Attic/building air intake? • Ensure there is enough!

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Powered Inlets Weighted or Velocity Inlets

As Always, Inlets Are Key.

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Attic Air Intake with Proper Soffit Construction

Cold winter air

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Negative Pressure Inlets and Open Doors

•  24 crate farrowing room has 12,000 cfm of summer capacity (500 cfm/crate) –  15 ft2 of total inlet capacity

needed to maintain inlet velocity at 800 fpm.

•  One 6ft 8in x 3 ft walk-in door left open –  inlet capacity to room

increases by 20 ft2 and inlet velocity drops to 342 fpm.

Incoming airspeed too low Air comes into the room and drops

Incoming airspeed correct Air moves well into the room and circulates

800 fpm

342 fpm

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Tilting Fans for Cooling Effect (View from Center Aisle toward Sidewall)

Spacing ~ 25 x fan diameter (ft)

Fans Used for Supplemental Cooling

Fans Used for Distributing Air

Space to utilize throw

Throw ~ 10 x fan diameter (ft)

Tilt fans to expose pigs to moving air stream

No tilt results in air circulation without exposing pigs to moving air stream

Dr Rick Stowell, Extension Ag Engineer, University of Nebraska

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When to turn on stirring fans?

•  When used for cooling: 3-5oF lower than drip cooling or sprinkling (75-78oF)

– Goal is to first use direct airflow to cool the pigs, then add water for evaporative cooling.

•  If making up for poor air distribution, some fans can always be on, but they must be re-oriented (along ceiling) for colder weather. 24

Tunnel-Ventilated Gestation Barn w/Evaporative Cooling Pads 24

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Evaporative Cooling Pads

(KoolCell Pads) –  Incoming air drawn through wet pads –  Air evaporates water from pads

•  Temp reduced •  Moisture increased

–  Temperature will decrease until RH nears 85%. –  When incoming air is humid (relative humidity >70%),

air temp decrease will only be 5-10 F. –  When incoming air is relatively dry (<55% RH), air

temp reduction may be 15 F or more.

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Impact of Relative Humidity on Effectiveness of Evaporative Cooling

Outside RH%Outside Temp (F) 30 50 70

Pad Exit Temp (F) 80% efficiency

76 62 66 70

84 67 73 78

92 73 79 85

100 79 87 93

Meyer and Van Fossen, ISU, 1971

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1) Producing desired airspeed [ Ceiling height x Room width ] x Desired velocity

[ 8 ft x 60 ft ] x 300 ft/min

= 144,000 cfm

2) Producing desired air exchange # females x 250 cfm/pig

500 hd x 250 cfm/hd = 125,000 cfm è 260 fpm 850 hd x 250 cfm/hd = 212,500 cfm è 445 fpm

Sizing Tunnel Ventilation: Gestation

Use the Higher Fan Capacity:

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Design of Evap Coolers

Pad efficiency drops sharply at >400 fpm

850 females x 250 = 212,500 CFM 8 x 60 x 300 = 445 fpm

6 ft pad height 212,500 / 400 = 531.25 ft2 531.25 ft2 / 6 ft high = 88.5 ln feet

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When to turn on pad pumps?

•  Full tunnel ventilation first

•  Minimum outside temperature – your system specifies?

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Evaporative Pad Cooler Issues

•  Uneven Wetting •  Water Quality

– Algae growth – use dilution of copper sulfate – Mineral deposits

•  Routinely drain 10-15% •  Alternative – muratic acid or vinegar in water

•  Covers – Static pressure control point – Winter

http://www.aerotech-inc.com/www/Help.nsf/ByKey/RSCZ-628NBG/$file/qp1511.pdf

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Evaporative or Direct Cooling

•  Wetting the pig and then allowing moisture to evaporate off provides substantial cooling (1050 BTU’s lost for every lb of water evaporated)

•  Good systems wet the pig & allow the water to evaporate –  Increased air speed – Lower humidity = increased evaporation so

want intermittent wetting •  Sprinkling & dripping

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Sprinklers

•  Used for grow-finish pigs

•  Want time interval & nozzle size to deliver 1 gal of water/hr/10 pigs

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Sprinklers

•  Start sprinkling at 80 0F & wet all pigs •  Once pigs are wet, stop sprinkling and

allow water to evaporate off •  If continually wetting, relative humidity in

the barn will rise & evaporation will decrease

34 Timers on sprinklers allow for pen drying

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Sprinklers

•  Non-corrosive nozzles •  Should provide a solid cone of water

droplets •  Do NOT want a “fogger”

– Fogger cools the air – Raises relative humidity & decreases

evaporation •  Sprinkler cools the animal •  Place nozzle 6’ above the dunging area 36

Sprinkler vs Fogger 80 F set point

Control (no cooling)

Fogger (small

droplets, always on)

Sprinkler (1 on, 29 off)

ADG, lb (I) ADG, lb (II) (I) – 140 lb on test wt, 56 d trial (II) – 150 lb on test wt, 42 d trial K State, 1983

1.15

1.44

1.28

1.56

1.54

1.74

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Drip Cooling for Sows

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Water Drip and Sow Performance

Drip Off Drip On

ADF, lb/d 7.8 12.3

Wt loss, lb 47 31

Days to estrus 5.2 4.7

McGlone, 1998 http://www.moormans.com/Swine/TechBulletinHTML/S9333%20Heat%20Stress.htm

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Drip Cooling

•  Emit small droplets of water on neck & shoulders (areas of high blood flow)

•  Preferred method of cooling lactating sows –  Cool the sows but keep

piglets warm & dry

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Drip Cooling

•  Start at 80 0F •  Drippers should provide .5-1.0 gal/hr

– sized for minimal runoff from sow •  Dripper should be placed 20” behind front

headgate – Reduces feed wetting – Keeps young pigs dry – Wets a “high bloodflow” area

•  Make sure creep area stays dry

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Atomizer Cooling

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Summary

•  Evaporative cooling is most effective cooling system for swine

•  Water needs to be properly placed and at the correct flow rate

•  Increased air speed & lower humidity greatly increase evaporative heat loss

•  Sprinklers for G-F pigs & drippers for sows

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Questions???

Thank You