Curtains - quartiling the building
Motorised curtains are an increasingly popular way of
naturally-ventilating piggeries in hot climates - those that are not exposed to
strong winds in winter.
Motorised curtains are an increasingly popular way of naturally-ventilating
piggeries in hot climates - those that are not exposed to strong winds in
I see many in my travels. If the building is 'squat' - that is
fairly short and wide, then just one curtain down each side of the building is
satisfactory. A barn of, say, 35 to 40 metres in length and about 18 to 20
But I see many which are much longer than this, but little
wider, still with just one curtain running all the way down the sides which may
be 50 to even 100 metres long. Pigs in such buildings will have a much wider
temperature gradient with just one long curtain per side. It is better to
'quartile' such long barns by having two motorised curtains on each side, with
the ground plan thus divided into four quarters.
crosses the sky from dawn till dusk across an arc of about 180Ëš. This means that
different portions of the building will receive different heat intensities as
the sun moves across the sky during the day. Also the wind can blow from
different directions in the course of one day (or night). Having four curtains
driven by four motors linked to four sensors in the four quarters of the ground
plan - all linked to an overall temperature controller - provides a more stable
and less variable environment.
I have measured the temperature gradients
between a single curtain per side building and one of exactly the same design
and orientation which had been quartiled. The two curtain shed gave a typical
temperature gradient in cold weather ranging from 14ËšC to 9ËšC while the
quartiled one ranged from 14ËšC to 11ËšC. This meant that 74% of the pigs were in
the warmer sector of the four-curtain shed during the periods measured while
only 18% in the two-curtain shed were.
In terms of
results, the quartiled pigs showed an improvement of 0.2 feed conversion rate
(6.25%) and reached slaughter eight days sooner in winter. The payback on the
extra cost was ten months -say two winters discounting any summer
In fact in hot weather there were 12% dirty pens in the
quartiled buildings and 32% in the two-curtain version - this at a 29.3ËšC
maximum daytime temperature. I find wrong-mucking tends to be a disadvantage to
any form of curtained ventilation, but this is lessened by spraying and stopped
altogether by installing an airbag distribution system.
gradients mentioned above are drawn out as per ground plan in my textbook
'Pig Production Problems - A Guide to their Solutions', pages
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