The Rural Voice, 1995-11, Page 27distances between large livestock
operations and residences, Caldwell
said. Some municipalities are
creating bylaws regulating the
distances between liquid manure
storage tanks and residences.
ome of the issues posed by non-
farm pressures on livestock
operations are beyond the
mandate of municipal
governments but planners will have
to try to address the concerns both of
farmers and non-farm residents in the
coming years. (Huron is now
undertaking a revision of it's official
plan, adopted in 1973 and generally
regarded as a provincial leader in
protecting farm land from urban
encroachment.)
Switching from local political
concerns to international ones, Doyle
outlined how the NAFTA panel
would work in the U.S. challenge to
Canada's dairy and poultry tariffs put
into place under GATT's tariffication
of import controls. He explained that
Canada wo n the coin toss to choose
a panel chairman and a Belgian
lawyer had been named. Canada
would pick the two U.S. panel
members from a list of 10 nominees
submitted by the U.S. while the U.S.
would do the same from Canada's
list.
When the hearings begin he
warned producers to be ready for the
Canadian media to jump to accept
U.S. arguments against the tariffs.
"Ontario media are not supportive of
supply management. When the U.S.
position is unveiled there will be a
frenzy to agree with the U.S.
position." Industry leaders are
preparing to counter these claims
with facts, he promised.
The Canadian government
expects to win the challenge
because supply management
import controls were protected
under NAFTA and the GATT tariffs
are simply replacing these. Europe is
watching the results of the challenge
closely, he said. Europeans are
worried about U.S. attitudes. A
Cool ideas for a hot poultry problem
Even in severe heat waves such as those that hit
southern Ontario in July there are precautions that
poultry farmers can take to reduce heat stress losses,
Norman Bird told the audience at the Poultry Producer
Update seminar in Holmesville.
Even on July 14, the hottest day of the heat wave and
the hottest day on record for that date
at nearly 40 degrees C (100 degrees F)
on the dry bulb thermometer at London
weather office, the wet bulb
temperature was only 29 degrees C (84
degrees F). The difference between the
dry bulb and wet bulb temperature is
the cooling potential.
That potential can be met in part by
moving the air faster over the heads of
birds. Since birds shed heat by
conduction and convection from their
body surfaces, especially around the
head and neck where the blood can be
space per bird can provide more space for air movement
around each bird.
Conventional cross -fan ventilation depends on
adequate ventilation system capacity and a good
uniform rolling air pattern to create air movement at the
bird level in hot weather. Make sure the inlet air drops
in the middle of the pen and returns to
the inlet side to create the two reverse
roll patterns. Watch for dead air
pockets at the corners and along the
walls.
The capacity of the ventilation system
should be measured allowing at least
one air change per minute (about 7-10
cubic feet per minute per foot Icfml —
and in extreme heat it should be at least
10).
To allow more inlet capacity
four -foot tip -in doors have been cut in
some barns.
Tunnel ventilation, with its large, end -mounted fans can
provide higher velocity ventilation at the bird's level.
U.S. barns are typically 40 feet wide by 400 feet long
with six to seven 48 -inch fans on one end and 330 sq.
foot of inlet in the opposite area. This gives about three
square foot of opening per 1000 cfm for an incoming air
velocity of 400 feet per minute. Canadian barns, though
shorter, still need the same number of fans to create the
same velocity. Four fans, however, would still create 200
feet per minute air flow. These should be matched with
2.66 sq. ft. of inlet door per 1000 cfm.
Natural ventilation takes advantage of wind to create a
large air change potential at low cost. A two miles per
hour wind will provide one change per minute with a
four foot curtain. A five miles per hour wind is equal to
440 feet per minute and is very effective at cooling.
Circulating fans inside the barn may be needed to boost
the speed of the air movement over the birds to 100 to
150 feet per minute.
In the southern U.S. fogging systems and cooler pads
have been used to further cool barn temperatures.0
Tunnel ventilation can move air
quickly over birds.
brought close to the skin, air speed improves convection
heat loss. A speed of 200 feet per minute is equal to a
drop in temperature of seven degrees F. Birds also lose
heat by evaporative cooling from the lungs. Above 82
degrees F broilers will drop their wings and begin to
pant and evaporative cooling becomes the major method
of heat loss. Radiation can also be a factor in heat loss
especially if there is a warm ceiling or wall radiating to
the birds.
Bird said the first steps for producers should be to
block solar radiation by properly insulating walls and
particularly ceilings. Make sure there is adequate attic
ventilation to get heat out of the space above the ceiling.
Light coloured roofs, walls and fan hoods will reflect
more heat than darker colours. Spraying water on sun -
heated walls and hoods can cool the inside temperature.
Make sure thee is a clear path for the wind. A field of
corn around the barn can slow the wind, losing cooling
capacity.
Thin litter on floors creates cooler floors. Deep litter
creates heat through composting. Increasing the floor
NOVEMBER 1995 23