A2B-Lancaster Farming, Saturday, June 23 2001
Penn State Cooperative Extension
Capitol Region Dairy Team
Dan McFarland
CIRCULATION FANS
CAN HELP REDUCE
HEAT STRESS
Dan F. McFarland
Extension Agent
Agricultural Engineer
After providing shade and an
adequate air exchange, air move
ment can be beneficial by reduc
ing heat stress in dairy cattle.
Air moving across a cow’s
body can improve the rate of heat
loss from her body and also aid in
evaporation of moisture from her
skin. Circulation fans in the ani
mal space accomplish this by
mixing air and minimizing “hot
spots.”
To help reduce heat stress dur
ing hot weather, proper selection,
placement, and operation of cir
culation fans is important. Stud
ies indicate that an air speed of
220 440 feet per minute (2.5-5
mph) is necessary to be beneficial
for dairy cattle. Most circulation
fans are able to produce air velo
cities greater than this for a dis
tance of approximately 10 times
their diameter (24 inches in di
ameter for 20 feet; 36 inches in
diameter for 30 feet, etc.). How
ever, the guard design, blade de
sign, motor size, and blade speed
all affect performance. Dust and
dirt build up on the blade and
guards can also greatly affect
performance.
Some fan manufacturers claim
“their” fans are able to move air
in the 2-5 mph range for up to 20
times the diameter. However, my
evaluation of these fans (with
cows in the area) indicates that
the spacing should be no more
than 15 times the diameter.
Cows influence the effective air
movement. Air leaving the fans
strikes standing cows and creates
a “wind shadow” or an area of
little air movement for cows that
are downstream. Spacing the
fans 10 times their diameter or
less (in the direction of airflow)
usually provides uniform, effec
tive air movement.
In naturally ventilated shelters,
the direction of airflow should
follow the predominant prevail
ing winds during warm weather.
However, if quality fans are
placed as recommended, per
formance is still acceptable when
breezes come from the opposite
direction.
Circulation fans are usually in*
stalled with the bottom 7 to 8 feet
above the cow alley (out of cow
and equipment reach) and tilted
20 to 30 degrees downward.
Circulation fans should be
placed in the areas where the
cows spend the most time the
resting, feeding, and the milking
area. In tiestall barns, a single
row over each stall row is ade
quate, while freestall and loose
housing systems generally require
multiple rows of fans.
Typical recommendations for
freestall shelters place fans over
each stall row and at the feeding
area. Sometimes a single row of
fans is used over head-to-head
rows of freestalls. However, in
these head-to-head arrange
ments, the fans should be spaced
no further than 8 times their di
ameter to provide adequate air
flow.
In tiestall shelters, fans are
usually placed above the front
third of the stall. When sidewall
fans and perimeter inlets are
used to provide an air exchange,
some fan suppliers suggest that
fans above one stall row move air
in one direction while the other
row moves in the opposite direc
tion to circulate the air more
evenly. However, circulation fans
used in conjunction with tunnel
ventilation systems should en
courage airflow in one direction
toward the exhaust fans.
Circulation fans are useful
when the temperatures go above
70 degrees Fahrenheit (or so) in
the animal area. Thermostats or
sensors with NEMA 4 enclosures
should be installed in the animal
area and kept clean to accurately
sense the conditions. During peri
ods of hot weather, circulation
fans improve the cow’s ability to
get rid of heat at night. Research
at the University of Missouri
found that core temperature of a
cow could be reduced up to 1 de
grees Fahrenheit (F) by using cir
culation fans to aid cooling at
night compared to using fans
during the day only.
The most effective heat stress
abatement systems use circula
tion fans along with spray or
evaporative cooling during hot
weather. The next article will dis
cuss cooling systems for dairy
cattle using water.
FORAGING AROUND
the newsletter of the
Pennsylvania Forage and
Grassland Council (PFGC),
includes several farm features
with a focus on pasture quality.
The special summer section
will be included with
Lancaster Farming July 14.
Another section, the fall PFGC
issue, is scheduled Sept. 15.-
Somerset County Day
At The Farm Cancelled
GAY BROWNLEE
Somerset Co. Correspondent
SOMERSET (Somerset Co.)
The annual Somerset County
Day at the Farm has been
cancelled by the Somerset Coun
ty Farm Bureau, according to
Harold Shaulis, Farm Bureau
president and chairperson of the
event.
Normally the event is sched
uled the last Sunday in June,
which, this year, would have been
June 24.
In arriving at the difficult deci
sion, Shaulis said the agency had
to consider livestock at the host
farm in view of the potential that
some 1,500 visitors could be ex
pected to attend the summer
event.
“We did not feel comfortable
to ask anybody to put their farm
at risk,” said Shaulis. “There are
too many ‘if s,”’ he said.
‘There are a lot of disappoint
ed people, but they understand.
We want to come back bigger
and better next year.”
Lynette Ely, secretary of the
Somerset County Maple Produc
ers Association, which at the last
three events has served maple
sundaes to the public, was down
to-earth about the news and took
a practical view. “If s one of the
things that go with farming. You
roll with the punches,” she said.
“Its sort of symbolic. Some
years are good and others
aren’t,” said Ely.
Interestingly, Shaulis said that
very few people ask about foot
and mouth disease. There tend|s
to be a blase attitude. In genera),
when people interact with each
other and the livestock as in
the very popular petting zoo to
some, the risk potential doesn’t
seem to be an issue.
“The big thing is (foot and
mouth disease) is not a ‘people
thing,’ and they take a lackadai
sical attitude about it,” said
Shaulis.
Prevent a Foot and Mouth Catastrophe
Watch for Signs of Foot and Mouth Disease
Clinical signs of Foot and Mouth Disease (FMD):
Early Signs may include:
- Fever
- Off feed
- Reluctant to move
- Excessive squealing when forced to move
Followed by blisters:
- Just above the hoof and on the heels
- Between the cloven hoofs
- On the snout
If you suspect Foot and Mouth Disease FMD in your herd:
Do NOT under any circumstances move any animals off the farm
Immediately report suspected case to either the Pennsylvania Department of
Agriculture (PDA) or the United States Department of Agriculture (USDA).
Contacts;
PDA - Dr. Phil Debok at 717-783-8300
USDA - Dr. Lynne Siegfried at 717-782-3442
A veterinarian especially trained to diagnose foreign animal diseases will
come to your farm to make the diagnosis.
Government programs are in place to reimburse farmers for the value of
their animals sacrificed in the control program.
Shaulis said the success of
Somerset County Day at the
Farm is owing to a combined ef
fort of many people who handle
the afternoon program. Some 100
volunteers roll up their collective
sleeves 3-4 months in advance
and work to showcase agriculture
through commodity samples,
demonstrations, hayrides, and so
forth. Monetarily, the investment
for Day at the Farm, Shaulis
said, is $5,000.
“The Farm Bureau organizes
it, but we really rely on other peo
ple’s expertise for segments of the
program,” said Shaulis.
That would include represen
tatives from the dairy, beef, lamb,
maple, potato, beekeeping, and
grain industries; 4-H clubs; hoof
trimmers; sheep shearers; veteri
narians; equipment dealers and
other agri-businesses; chemical
dealers; and other exhibitors.
Among those helpers, for in
stance, Dorothy Naugle handles
dairy promotion from inside the
Little Red Bam owned by the Al
lied Milk Producers Cooperative,
Inc. She is the cooperative’s dairy
marketing specialist and usually
assisted by the dairy princess,
dairy maids, or volunteers from
Provided by the Pennsylvania Pork Producers Council
Keep by the Phone
the local dairy promotion com
mittee.
Naugle reported they are going
to miss the 2001 Day at the
Farm, but the feeling of Allied
Milk Producers is “better safe
than sorry.”
Visitors are known to line up
at the Little Red Barn for cool
and creamy refreshments. The
same is true when the mobile
dairy bar is used at events
throughout Pennsylvania and
neighboring states.
The event provides a great
venue to reach uninformed ur
banites who otherwise couldn’t
tell you where their food comes
from.
“The main objective is to pull
in people from urban areas and
educate them,” said Naugle.
Naugle said up to five area
dairies contribute the ice cold
milk used at the event.
“Somerset County is called the
‘Land of Milk and Maple,’ and it
is very opportune that the two
products can be presented togeth
er (at Day at the Farm),” said
Ely.
She said that in some ways,
though, it is nice to have a break
from all the planning.