Infrastructure
Paddocks & laneways
Portable shade structures
The most effective way of reducing heat load is to block
solar radiation by providing shade. When not enough
natural paddock shade is available, artificial shade can
be used to minimise cows’ exposure to solar radiation.
Portable paddock shade structures may incorporate
shade cloth or corrugated iron roofing.
Wheels or skids enable the structures to be towed
behind a tractor or four-wheel motorbike to where they
are needed.
Priorities for cooling cows
1. Use shade first
Minimise heat gain – block solar
radiation
2. Use sprinklers and fans
Maximise heat loss – encourage
evaporative cooling
|
Portable paddock shade
These structures are very effective when no other
cooling is available in paddocks, such as overhead
sprinklers (e.g. lateral move and centre pivot irrigators).
These shade structures can be located in paddocks/
laneways, in dry corners of centre pivot irrigated
paddocks or near portable feeding troughs and
hay rings.
Strengths:
- Enables you to bring the shade to the cows, as
opposed to cows to the shade.
- Best suited to smaller herds.
- Can be readily moved with the animals, or moved
to cleaner, drier locations close to feed and water
when necessary.
Limitations:
- May need several structures to provide sufficient
shade for all animals.
- May lead to localised pugging, nutrient build-up or
compaction if not shifted regularly.
- A time cost needs to be allocated to shifting shade
structures.
- Shorter useful life than a permanent shade structure.
- Vulnerable to high winds.
Other options
A simple, low-cost design, but one
that might not be suitable in
windy
conditions. Note some shade cloth tears along the edges.
An iron-roofed structure will
re-radiate heat on the cows underneath,
so where possible create a larger gap between the cows and roof.
Keys to success
- IF LOCATED near
property
boundaries,
shade structures should be positioned to take
advantage of any natural tree shade from
neighbouring vegetation on road reserves.
- RE-LOCATE STRUCTURES
if
manure
builds up or the ground underneath is muddy.
This reduces the risk of mastitis around calving
time – the risk is particularly high if the condition
of cows’ teat ends is poor.
- BEFORE YOU build
your own
structure,
seek professional advice from a registered
engineer or builder.
- IF USING shade
cloth,
install it properly
under tension, so it is not damaged by winds.
Make sure that it blocks at least 80% of
sunlight.
- SEEK PROFESSIONAL
advice
from a
registered builder or structural engineer, as the
height of the portable shades will affect wind
loads on the structure.
- WIND LOAD will
increase
with roof height,
and therefore the base needs to be heavier and
wider to prevent the wind from tipping the
structure over.
- ENSURE THERE is a
gap
between the
portable sections of the roof (when raised), so
that heat can be vented through the top of the
structure. This is especially important for iron
roofed structures.
- ENSURE THE footings
and
the base of the
structure is wide enough to support the roof
spans – this needs to be worked out for the
specific individual structure.
|
