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When to cool?
Cooling is essential to help pigs cope with heat stress. All
pigs can die from heat stress, especially after bullying. |
Breeding boars
>24 degrees C
|
Semen production can be
significantly affected for 6 weeks if the boars are subjected to
>30 degrees C for more than 2 days. |
Farrowing sows
>24 degrees C |
Live births are reduced and
stillbirths increase as sows are fatigued. |
Lactating sows
>24 degrees C |
Heat stress reduces milking
capacity and feed intake, which affects weaning weights and
increases weaning to service interval. Not eating can result in
excess maternal weight loss. |
Gestating sows
>24 degrees C |
Inadequate intake and increased
stress levels result in reduced farrowing rate, birth weights
and litter size. |
Growing/
finishing pigs
>22 degrees C |
Feed intake and
FCR significantly
negatively affected by heat. Cooling helps to keep pigs clean
and reduces disease particularly of the digestive and
respiratory tracts. |
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How to cool and when: |
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Farrowing house drip cooling: |
- Suspend drip cooler 30 cm (12 inches) from
top of crate.
- Discharge on to the sow's neck and shoulder
area. It should be located far enough back so there is no
chance of getting water in the sows ear while lying down.
- Ensure the sow cannot reach the nozzle with
her mouth.
- Run system so that the floor does not get
wet. The system should run only long enough to produce minimal
run off from the sow's body. This is particularly important
when solid farrowing floors are used.
| Suggested
cooling times |
| degrees
Celsius |
On (minutes) |
Off
(minutes) |
| 24-28
|
1 |
20 |
| 28-30 |
2 |
10 |
| 30-32 |
3 |
5 |
| 32+ |
4 |
5 |
|
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Spray cool installation: |
- Mount the spray nozzles over the dunging
area of the pen. Locate one per pen at a height to produce a
spray pattern large enough in diameter to cover the required
area. Need to produce a coarse droplet spray not a fine mist
of fog.
- Suggested use 1-3 minutes on and 15-30
minutes off. The optimum temperature at which to begin
spray-cooling pigs depends on the age, size of animals and
number of pigs in the pens.
- Aim to wet all the animals in the pen and
then turn off the system to allow the water to evaporate from
their skin before restarting. Need to vary on and off
intervals according to ambient air temperatures, humidity and
behaviour of the pigs.
|
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Dung Training: |
- The cooling system can be used to assist in
dung training.
- Use the system for 2 minutes on and 60
minutes off for the 1st 2-3 days upon entry.
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Wallow maintenance: |
- Ideally allow wallow to run dry once during
the summer and start a new wallow to help control
leptospirosis.
- Ensure wallows do not collect large rocks
and other sharp objects which can damage legs in unsuspecting
pigs.
- Do not use water supply as a wallow.
- On very sandy soil it may be necessary to
build a wallow from soil and clay.
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Evaporative Cooling: |
| While evaporative
cooling can help to significantly reduce the room temperatures
and are ideal in boar studs. They need maintenance and looking
after. |
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Maintenance: |
- Ensure nozzles are cleaned at each
all-in/all-out.
- Check for evidence of clogging with lime - commercial household de-mineralized solutions can be used. Do
not use strong acids or metal pins to unclog blocked nozzles.
- Check spray system is not spraying in
feeders.
- Ensure floor is not becoming too wet.
- Observe each nozzle when spraying and
ensure water is being diverted to the correct location on the
animals.
- Check for leaks at the fittings daily.
- If a controller is used, ensure the
controller works within expected operating parameters at least
quarterly.
- Check floors are not becoming too polished
and remain wet.
- Clean water fitters as required, minimum 4
times a year.
- Ensure in winter time the system is
protected from freezing.
- Ensure evaporative cooling system has no
holes in it.
- Check for rodent damage to cooling system.
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Alarms and safety
mechanisms: |
- Under regulations where the pigs have
automatic ventilation systems alarms and fail safes must be
fitted.
- These should be checked daily and audited
weekly
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Problems if
cooling system improperly used: |
Farrowing house
|
Wet farrowing floors can increase
scour problems. Sows may slip on damp floors. |
|
Boar/gestation |
Floors may become slippery if
pigs remain wet. At breeding animals can be injured if they slip
on the wet floor. They can over cool and result in abortions.
|
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Grow/finish |
Wet pigs, which are over cooled,
particularly if high ventilation rate may lead to increased
stress. |
Spray/not spraying
correctly |
If spray-cooling system sprays
into the feeders this can block feeders. If they spray on the
walls this can damage insulation. |
|
Storage tank position |
Note: hot water does not provide
cooling. Ensure main storage tanks are properly placed and not
subjected to direct sunlight |
|
Humidity effects |
High humidity can interfere with
evaporative cooling. |
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