JAYNE SEBRIGHT
Lancaster Farming Staff
EPHRATA (Lancaster Co.) Dairy profits can be im
proved dramatically by proper ventilation in tie stall and
free stall facilities. As the temperature rises over 70 degrees
Fahrenheit, dairy cows reduce feed intake, milk production,
and reproductive efficiency.
According to the Ohio State University, ventilation sys
tems serve an important function in dairy barns, maintain
ing a comfortable animal environment. Typically, a mature
dairy cow will breathe out four to five gallons of water per
day as water vapor and produce 2000 to 2400 BTU per
hour.
Ventilation systems continuously remove heat, moisture,
and odors from the barn and replenish the oxygen supply by
bringing in drier, cooler outside air. Adequate air exchange
also removes gases that can be harmful to both animal and
operator health.
The two standard types of ventilation in Pennsylvania
dairy facilities are natural and mechanical ventilation.
While natural ventilation depends on air movement and
natural weather patterns to move air through the building,
mechanical ventilation utilizes tunnels, fans, and forced air
to improve air quality.
The Hissongs of Mercer Vu Farm in Mercersburg, Frank
lin County, milk 235 cows with a rolling herd average of
24,750 pounds milk, 805 pounds fat, and 766 pounds pro
tein.
When father Ron and sons Rick and Rod decided to
expand their herd from 145 cows three years ago, they de
cided to build a new naturally-ventilated freestall barn.
“When we built the barn, we never heard a lot about
mechanically-ventilated systems,” said Rick Hissong, one of
two sons working on the family farm. “We relied heavily on
Penn State cooperative engineer Dan McFarland’s advice to
build our barn.”
The barn was built with 14-foot sidewall openings and a
36-inch wide by 36-inch tall open ridge at the peak of roof.
“The barn was designed with the goal of maximizing pro
duction and controlling costs,” said Hissong. “When we
look into the future, our next goal is to expand so that this
farm can ship a tractor trailer load of milk a day. The barn
was designed with that in mind.”
According to Hissong, a primary consideration when
building a naturally ventilated barn is its location. “We’re
sitting up on a hill, so there is always a nice breeze going
through the barn, even during the hot summer months,”
said Hissong. “If you were sitting down in a valley, a natu
rally-ventilated barn might not work as well.”
Before building the barn, the Hissongs used to see milk
production drop anywhere from 15 to 20 pounds during the
Well Ventilated Barns Prevent
Heat Stress And Improve Air Flow
Rick and Rod Hissong of Mercer Vu Farm use nat
ural ventilation to keep their cows cool and com
fortable year-round. The naturally-ventilated
freestall barn helps maintain milk production
during summer months.
summer. “Now we only see at most a five to seven pound
loss during the hottest months,” said Hissong.
The barn is equipment with five-foot curtains that are
used during the wintertime, but Hissong said that they are
rarely put up all of the way. Even when the curtains are
completely closed during the coldest months, there is still a
sixteen-inch airflow opening.
Slotted floors allow manure to flow in channels under the
barn and away from the cattle. 36-inch diameter fans are
spaced every 36 feet in the barn.
The only downside of the barn is that rain occasionally
will come in the open ridge roof and fall in the center of the
feed alley.
“That doesn’t bother me in the least,” said Hissong. “I
like the complete openness of the open ridge. If I had it to do
over again, I would build the barn basically the same way.”
“The air quality in this barn is very good,” said Hissong.
“When you walk in here, it doesn’t smell like a dairy oarn.”