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LANCASTER FARMING'S
ANNUAL
DAIRY ISSUE
June 4
Reaching Over 50,000 Dairy & Farm Industry Readers
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Special dairy stories and • What s new m dairy research
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Glenn's
Udderings
By
Glenn A. Shirk
Lancaster Extension
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DEADMNB FOR AOS • MAY 27
Dairy Agent
HAY, STRAW
& GRAIN SALE
Every Thursday at 1 p.m.
(Rt. 30,10 miles east of Lancaster
In Paradise. PA)
For Info. L. Robert Frame, Sr.
717-442-4181 business president
215-458-8518 home
Dairy bams can be a comfort
able and healthy place for cows on
a hot summer afternoon that is,
if the bam is properly ventilated.
Bams provide cows shade, easy
access to fresh feed and water plus
a clean, comfortable place to lie
down and rest
There are many ways to venti
late tie stall bams, one of which is
tunnel ventilation. It works well in
narrow bams. In bams that are 36
to 40 ft wide, four 48 in. fans are
installed in one end of the bam,
with all the air inlets located at the
opposite end; all other air inlets
are closed. About 2.S sq. ft of air
inlet area is needed per 1,000 cfm
of fan capacity. With four 48 in.
fans that amounts to 200 sq. ft. For
Auction will continue
all year long
Vintage Sales
Stables* Inc.
a 40 ft wide bam, that requires a 5
ft wide slot across the full width
erf the bam, or its equivalent This
amount of fan capacity should cre
ate about a 3-4 mph breeze and
provide 1-2 air changes per
minute.
A few words of caution. Be sure
to make provisions for ventilating
the bam in the event of a power
failure! Tunnel ventilation is a
good hot weather system; it is not
a good year-round system. In
cooler weather, when air flow is
considerably less, it takes too long
for air to move from one end of
the bam to the other; cows at the
exhaust end of the stable will be
breathing more moist, germ-laden
air.
If you already have a good
exhaust ventilation system with
air inlets distributed uniformly
around the stable, you can simply
add more exhaust fans to increase
air exchange to 1,000 cfm or more
per cow. Be sure the air inlets are
large enough to accommodate this
increased flow of air. This system
should keep the air fresh, but it
won’t create as much breeze as the
tunnel system described earlier.
Another way to get fresh air and
a breeze to cows’ head and shoul
der areas is to install a pressurized
duct over the curb area of the feed
bunk or manger. These ducts can
be of polytube or rigid construc
tion. They can be placed beneath
the stable ceiling if there is suffi
cient ceiling height, or constructed
above the ceiling (ie. in hay mows,
on bam floors or in attics) with air
being discharged through holes
cut in the ceiling.
The ducts should be large
enough to accommodate 400-500
cfm of air per cow, and you’ll
need about 1 sq. ft of duct cross
section area per 1,000 cfm of air.
In other words, an 8,000 cfm fan
would require 8 sq. ft.; that’s a 3.2
ft. diameter tube or a duct that is 2
ft. x 4 ft. or 3 ft. x 2 ft. 9 in. If one
4,000 cfm fan could be placed at
each end of the duct, the cross sec
tion area of the duct would only
need to be half as large; a 2.25 ft.
diameter tube or a duct that is 1 ft.
x 4 ft. or 2 ft. x 2 ft would be suf
ficient. In addition to being able to
use a smaller duct, two fans per
duct has another advantage; you
can run only one fan in cooler
weather when less air movement
is needed.
In pole bams, the ridge and side
walls can be opened up to encour
age greater rates of air exchange.
s ifltoditir f , «W*37
Ideally, the side walls should be
opened down to stall bed level.
This can be accomplished with
curtain walls, removable wall
panels, tilt-out panels, etc. Tilt-out
panels are more of a maintenance
headache, but they can protect
stalls along the outside wall from
sun and rain. Two inches of ridge
vent opening are needed for every
10 ft. of building width, with the
minimum width of the opening
being 8 inches.
Many farmers have installed
circulation fans to create breezes.
They do chum up the air but they
do not remove moist, stale air and
replace it with fresh air. If there is
moisture present, the breezes can
produce some evaporative
cooling.
To create more opportunity for
evaporative cooling, cows can be
soaked with sprinklers at the feed
bunk and then encouraged to stand
in a breeze to cool off. The breeze
can be natural or fan-generated. If
sprinklers are used, provisions
should be made for handling
excess waste water. If used in
enclosed areas, sprinklers tend to
increase humidity levels of the
area. The increased discomfort
caused by higher levels of humidi
ty could erase any benefits gained
from evaporative cooling. If used
outdoors or in very spacious, well
ventilated feeding areas, sprink
lers will have minimal to no influ
ence on humidity levels.
If bams are poorly ventilated,
one of the best places for cattle
might be outside on a breezy,
well-sodded lot. Should you plant
trees or erect artificial shades in
pastures? Only if you have lots of
trees and if the shade is portable.
The big concern is, cows will
probably crowd under one tree or
crowd in the shade area and turn
these areas into a mastitis or foot
rot cesspool.
Another concern is, when cows
are lying in the shade they are not
grazing. The goal should be to
keep cows dispersed, keep them
eating and don’t let them linger
long in any one spot. In a pasture
situation, availability of fresh
water may be more important than
shade, and if you are looking for
portability of water, it could be
hauled by tank to individual pas
ture plots.
Keeping cows comfortable and
clean, and keeping them on feed,
can pay big dividends.
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