October 2024 - Journal F e - Flipbook - Page 7
Health
due to dirt buildup and wind resistance. “We take the
book value of the fan’s cubic feet per minute (CFM),
then multiply it by 90% twice to get a more accurate
real-world value,” En昀椀eld explains.
The role of outside cones on tunnel fans is also
highlighted. These cones help create a shaft of
air, improving air昀氀ow ef昀椀ciency. Without them, a
fan can lose up to 15% of its capacity. Over time,
cones can crack and wear out, so regular maintenance
or replacement is necessary to keep the system
functioning optimally. A good practice is to make
sure fan louvers get washed between turns, and when
weather allows, to power wash pit fans to ensure
optimal performance.
Calculating by Pig Size & Seasonality
Determining the correct ventilation rate based on
pig size & seasonality is critical for ensuring a healthy
environment. The minimum cold weather rule of thumb
is 2 CFM per pig for weaned pigs. “For a 1,000-head
room, you’d need around 2,000 CFM of air moving
through the barn. Knowing your fan size and output
helps ensure you hit that target,” En昀椀eld explains.
As pigs grow, the ventilation needs increase. A
30-pound pig might require about three CFM, while
a 50-pound pig would need around 昀椀ve CFM. It’s
essential to scale ventilation to match the pigs’ weight
and weather to avoid issues such as under-ventilation,
which leads to high humidity, or over-ventilation, which
can result in drafts and increased energy costs.
Managing Humidity Levels
Humidity is a major concern in swine barns. Dr. Blythe
advises maintaining humidity between 40% and 60%,
with 50% being the ideal target. High humidity not
only increases the risk of bacterial growth but also
contributes to respiratory problems in pigs. “When
humidity starts creeping above 70%, you need to
intervene,” he warns. “If it hits 80% or higher, the
environment becomes really conducive to bacterial and
viral growth, leading to poor respiratory health.”
“A damp pig is a sign that conditions need to be
addressed for the health of your pigs, your caretakers,
and your facility.”
that they’re not comfortable, regardless of what the
thermometer says. Let the pigs and the environment
guide your adjustments. Walk through the barn,
observe how the pigs lay, their movement, and any
signs of discomfort, then assess how it feels—whether
it’s too humid or gassy—making time for sensory
observation is a vital exercise.
Airspeed Control & Inlet Management
Proper airspeed ensures the ventilation bene昀椀ts the
pigs without creating drafts or dead zones. “You don’t
want the air coming out of the inlets too fast or too
slow,” En昀椀eld notes. “If it’s too fast, you’ll create drafts
that stress the pigs. If it’s too slow, the air will drop
straight down and won’t circulate properly.” Target
800-1,000 feet per minute (fpm) for power ventilation
stages. A realistic target for barns operating in
minimum ventilation (below set point) is 300-600 fpm.
Dealing with Cold Weather Ventilation
Cold weather presents a unique set of ventilation
challenges. “In cold weather, you want your minimum
fan (stages 1 & 2) ventilation bandwidths a bit wider
(1.5°-2°) with a 0.5-degree offset,” Dr. Blythe advises.
“That way, you’re controlling air昀氀ow without creating
huge temperature swings.” In colder climates, it’s easy
to under ventilate in an effort to save on heating costs,
but this can lead to high humidity and poor air quality.
By addressing these common challenges—through
regular maintenance, probe placement, and a focus
on air quality—farmers can signi昀椀cantly improve their
barn environments. Effective ventilation not only boosts
pig health but also improves farm productivity and
pro昀椀tability.
Monitoring Pig Behavior
Pig behavior is one of the most reliable indicators
of proper ventilation. If pigs are piling up, it’s a sign
AIR
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