Don Bennink is one of the most innovative producers around, so when he tries something new, other people perk up their ears.
photo courtesy of jake martin
Within the past five years, he has put in four tunnel-ventilated barns — two of them retrofits of existing free-stall barns and the other two brand new. He completed the first retrofit in 2001 because he wasn’t satisfied with the existing natural-ventilation systems for cooling cows. “I just didn’t think they were doing the job,” he says. “I wanted more (cow) comfort through the summer.”
So far, Bennink is pleased with the way the tunnel-ventilated barns have performed in the
As more and more data are obtained on the performance of tunnel-ventilated barns, more and more producers may follow suit. The data on the barns look good so far.
Requires extra management
This is not to suggest that the tunnel-ventilated barns are ideal by any means. There are challenges, and the barns require a high level of management for success, says Jake Martin, consulting agricultural engineer in
In the Southeast, the high humidity presents a challenge. Tunnel-ventilated barns with evaporative-cooling systems lose much of their efficiency when the humidity gets above 90 percent. Therefore, it becomes a matter of balancing ambient air conditions outside the barn with those inside.
Other management issues include handling extra automation, having backup ventilation systems in place, keeping fans clean, maintaining negative-pressure conditions inside the barns, and directing the air where it does the most good.
The type of tunnel-ventilated barns suited for a southern climate cost about 25 percent more than the standard naturally ventilated barns, Martin says. That can raise the cost from $1,200 per cow, on average, to $1,500. Extra items include exhaust fans, insulation in the ceiling, end-wall construction, curtains for the sidewalls, high-pressure cooling (foggers or misters) and other items.
Helps controls environment
Todd Tuls, owner of Double Dutch Dairy in
“In wintertime, you can keep the barns warmer and in the summer, you don’t have the heavy fly pressure compared to conventional naturally ventilated barns, and you can control your environment a little better (regarding air direction and wind speed),” Tuls says.
For years, Shenandoah Dairy in Live Oak,
This tunnel barn at North Florida Holsteins has fans on one end pulling air through the building. The other end of the barn is wide open, with no end wall in place. (photo courtesy of jake martin)
The primary reason for going with two tunnel barns (with 600 cows per barn) was the configuration of the farm, says Ed Henderson, co-owner of Shenandoah Dairy. The tunnel barns could be built close together and perpendicular to the milking parlor, which cut walking distance for the cows.
Yet, there is a definite cow-cooling benefit,
“I’m happy with what I’ve done. But can I say I am milking more with a tunnel-ventilated barn? I don’t know,”
Reduces heat stress
Martin, who helped design the tunnel barns for both Henderson and Bennink, says tunnel-ventilated barns may become more common in the future if the data from existing barns continue to look favorable.
“However, I don’t think they will ever completely take the place of a well-designed ‘standard’ free-stall barn since many producers are either unwilling or unable to accept the challenge of the additional management requirements,” he adds.
Terry Smith, assistant professor in the animal and dairy sciences department at
“I think they provide superior cooling, and because of that they allow producers to maintain production — and income — during hot weather,” Smith says.
In an experiment three years ago,
A high-pressure cooling system with misters creates a fog-like effect in this tunnel barn at Shenandoah Dairy in Live Oak,
The tunnel-ventilated barn at
Bennink, who runs the 3,100-cow North Florida Holsteins facility in
“We can take a 95-degree day and bring it down to just under 80 (in the tunnel-ventilated barn),” Bennink says.
Some people might scoff at the idea of using misters in a humid area like north central
In other parts of the country, such as the
Has a place, even in the Northeast
Heat stress can occur even in
Curt Gooch, dairy housing environmental engineer with ProDairy/Cornell University, agrees the tunnel barns can do a good job when it comes to ventilating a barn and relieving heat stress. At many sites, they provide more predictable and more reliable air exchange in the summertime than naturally ventilated barns, he adds.
Gooch says he thinks tunnel-ventilated barns will become more common as producers learn the potential benefits.
May provide a payback
Systems vary considerably, so it can be misleading to compare research findings on the potential paybacks. An economic analysis done by Cornell researchers in 2000 indicates that the type of tunnel-ventilated barns suitable for the Northeast often can pay for themselves by boosting milk production by 2 pounds to 5 pounds per cow per day. And, in the Southeast, if the tunnel barns cost 25 percent more than conventional barns, a producer will need to boost his milk production accordingly.
While the economics are still not well defined, producers who have installed tunnel-ventilated barns seem to like them enough that they end up building even more.