The Rural Voice, 1980-03, Page 30Young stock needs
adequate ven ti/a tion
In ventilating any so-called "warm"
livestock housing barn. the general princ-
iple is to remove the moisture and gases
produced by the livestock by replacing the
inside air with that from outside. In colder
periods of the year, the cooler outside air is
warmed up to inside temperature thereby
lowering its relative humidity and increas-
ing the moisture holding capacity. This air
then picks up moisture given off by the
livestock which in turn is expelled to the
outside. Relatively small amounts of air
are required to look after moisture
production in winter; with rising outside air
temperature, this amount increases. Warm
weather ventilation rates have to be
relatively high to control heat build-up.
This in turn requires the use of some type
of variable air flow system to meet year-
round needs.
Air -flow volume is controlled by fan
capacity; this in turn is controlled by such
things as fan speed. diameter, frequency of
operation. etc. Air distribution is highly
important. particularly in the housing of
young animals such as dairy calves,
weanling pigs, etc. and is controlled by the
air inlet system. The proper design and
operation of the inlet system is every bit as
important as the exhaust system.
One of the problems often encountered
in ventilating facilities for young stock is
the fact that there is usually a relatively
Mailbox of the month
(Located In Culross twp
Bruce county)
PG. 28 THE RURAL VOICE/MARCH 1988
small number of animals involved. This
means the ventilation requirements are
correspondingly small. Unfortunately, at
this point in time. it is hard to purchase
ventilation equipment small enough to
meet the needs - particularly in winter.
Another problem is one of getting
uniform air distribution when the required
air movement for ventilation purposes is so
small. One possible way of overcoming this
is through the use of some type of
re -circulation equipment.
Still another problem in young stock
housing is the low heat production in
relation to the exposed surface area of the
building. The heat loss through the
building surfaces, together with the heat
loss in warming the in -coming ventilation
air, is often greater than the heat produced
by the animals. This necessitates the
addition of supplemental heat to maintain
the recommended air temperature.
There are two basic ventilation systems
currently in use in warm livestock
buildings. One is the conventional. cross-
flow system where a continuous inlet is
installed along one or more sides of the
building, with t:xhaust fans in an opposite
wall to expell the air. The second system
might be referred to as a package system,
usually employing some arrangement of
powered inlet as well as powered exhaust.
There are a number of variations to this
system - tubes, combined inlet and exhaust
units. and powered inlet with separate
powered exhausts.
One of the major features of the latter
type is the recirculation capability, where-
by one is able to achieve a constant air flow
within the building. With the addition of
heat. one is able to maintain a fairly
constant. uniform temperature throughout.
It also allows one to reduce the introduction
of outside air to more closely match that
required to control moisture production,
thus reducing supplemental heat require-
ments to a minimum.
In setting up a system to ventilate young
stock buildings, one of the major problems
is finding equipment that is small enough.
This requires modification and adaptation
of available equipment to meet the very
low air volume requirements of winter
ventilation.
One way of compensating for the lack of
low volume fan units in some cases is to
use a time clock of the 10 -minute repeating
cycle type wired in parallel with the
thermostat controlling the low level
exhaust fan. This will aid greatly in
achieving the total air exchange required
over an extended period using higher
capacity equipment. In addition, the use of
a simple electrical inter -lock between the
fan and heater will allow the addition of
supplemental heat only when required at
the minimum ventilation rate, thereby
reducing energy consumption to a mini-
mum.
Shur -Gain
Beef
Implants
two roads to profit
Two choices of proven
performance.
Synovex S and H: for steers
and heifers. Best for
600-900 Ib. cattle. Expect
improvements over non
treated cattle of 8%-15% in
daily gains plus better
feed 'efficiency. 120 day
effectiveness.
Ralgro: a non hormone
implant. Can be used with
calves or growing cattle.
Expect from 5%-10%
improved daily gains in feed
lot cattle, from 9%-15% in
450-500 Ib. cattle compared
with non -treated animals.
As a rule of thumb, implants
return at least ten dollars
for every dollar spent. See
your Shur -Gain dealer.
Walton
FEED MILL
Walton, Ont.
Brussels 887-6023