| Buildings
Control heat stress without
sacrificing natural light levels
Well-ventilated cow housing and adequate levels of
natural light in buildings are key elements to ensuring the
continued productivity of housed cows during the hot,
summer months.
raditionally, letting
natural light into
cow housing is
achieved by
installing fibre
glass panels and
low level GRPs in the roof of a
building. Whilst these components
help to increase light levels within
cow housing, they have the
adverse effect of focusing the heat
from the sun in certain areas of a
building; creating ‘hot spots’ and
increasing the chances of cows
located within these hot spots
suffering from heat stress.
Heat stress has a serious and
negative impact on cow health and
performance. The ideal ambient
temperature for optimum cow
performance is between 5°C and
25°C and if cows are exposed to
temperatures above this, they suffer
from heat stress.
Even on days where it might not
seem that warm, heat stress can
still be an issue due to relative
humidity levels. Only a small
increase in temperature is required
T
on a day with high humidity to
result in heat stress conditions.
Cows suffering from heat stress
will stand more, pant and increase
their internal blood flow. All of these
activities divert essential energy
away from milk production and, as
a result, cow milk yield drops
significantly.
This negative situation is
exacerbated by a heat-stressed
cow’s propensity to limit
movement; reducing their likelihood
of visiting the feed barrier. When
heat stressed, cows are also more
likely to have suppressed appetites,
so when they are at the barrier,
intakes will be reduced; further
limiting energy production and
yield.
It is clear that the negative
impact of heat stress is significant
and therefore taking steps to avoid
cows becoming heat-stressed is
vital. As such, dairy producers are
being advised to avoid the
extensive use of fibre glass panels
and low level GRPs as a source of
natural light in buildings and opt for
40 | Farming Monthly | June 2017
different alternatives.
One such alternative is to install
an open ridge in cow housing. The
benefit of this system is that the
open ridge provides a large outlet
for stale air to rise out of, aiding the
flow of air within a building. This
directly increases levels of
ventilation within cow housing - in
itself significantly reducing the risk
of heat stress within housed cattle -
whilst also letting in plenty of
natural light down the centre of a
building, away from cattle cubicles
and avoiding the development of
dangerous ‘hot spots’.
Marley Eternit have recently
launched a natural light protected
open ridge system which has all the
traditional light benefits of an open
ridge, but uses a clear GRP sofit
strip to also stop rain entering a
building. By using a transparent
strip made from polycarbonate
resin over the ridge, light is
channeled into the centre of a
building, high above cattle,
preventing ‘hotspots’, and this light
falls over the feed passage where
extra light is often in short supply.
The clear GRP strip lets in the
maximum level of light into a
building and reduces the need for
fiberglass roof panels and artificial
sources of light, whilst also
achieving the ventilation benefits of
a traditional open ridge.
Ensuring that a building is well
ventilated and that natural light is
let in (in a safe and controlled
manner) is key to minimising the
negative impact that heat stress
can have on housed cows.
Installing ridge systems that help to
increase airflow and allow
controlled natural light into a
building therefore represent an
efficient and cost effect mechanism
of achieving two important goals
that need to be secured in the
battle against heat stress.
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