A ventilation and cooling concept borrowed from calf barns is delivering fresh air and relieving holding area heat stress at Mystic Valley Dairy near Sauk City, Wisconsin.
Three years ago, dairyman Mitch Breunig was looking for a better way to keep his high-producing 400-cow herd cool while they awaited milking in the holding area. “Cow comfort and cow cooling are really important,” he emphasizes. “I’m always trying to find ways to keep cows milking and bred back and not stressed out.”
While making modifications to the adjacent utility room, he recognized that natural ventilation would no longer be a viable option for the holding area, as the south side would be obstructed, and the current cooling system with four 24-inch and one 48-inch direct fans had room for improvement.
In his search for alternatives, he came across a newspaper article debuting Dr. Ken Nordlund’s novel notion of positive-pressure tube system ventilation for holding areas.
Breunig was already sold on positive-pressure tube ventilation after watching it work wonders in his calf barn. A couple of years prior, the University of Wisconsin team outfitted the system in a 50-plus-year-old former stall barn where he raised calves.
“I always dealt with health issues in there, especially when the weather changed,” he recalls. “Now, it smells fresher, the air and the floors are much drier, and there are way less respiratory problems.”
Even though the innovation for holding areas was in its infancy, Breunig was certain it was the right solution for his facility. “I knew that’s what we should do,” he adds.
Soon after, Nordlund was out at the farm drafting a design for Breunig’s 40-by-100-foot holding area. He installed five tubes, each connected to a fan, running the width of the pen. Strategically placed air holes in each tube deliver fresh, cool air downward in between cows and uniformly across the pen.
“Most of the time, we push air across cows and the cows are so tight, the air is not getting between them,” Breunig says. “But this does that, and it gets the bad air out of the building.”
The fans are set to turn on when the holding area temperature reaches around 65ºF.
Seeing is believing
The positive-pressure tube system’s ability to reduce heat stress is not simply a perception. Breunig can measure the difference in temperature. “When we are milking, it’s always about 4 degrees cooler in the holding area than in the barn,” he says.
Reviewing the data from his rumination monitoring system, Breunig can see real-time trends that indicate cows are less stressed during warmer weather. “We can see what rumination rates do,” he explains. “We are able to keep them pretty stable; there’s not such a dip in the daily patterns. They are recovering more quickly.”
For this intuitive cow man, visual observation is a telling sign too that cows are not experiencing a spike in heat stress prior to milking.
“I like to walk into my parlor and see cows chewing their cud,” he notes. “That tells me they are not heat- stressed, so they are not heating up in the holding area.”
Breunig has also noticed improved fertility during the summer months. “Our reproduction was better in July and August than it was in June,” he says. “To me, that says the cows are cool.”
As far as milk production, Breunig sees cows recovering faster from temperature and humidity spikes.
Learning along the way
As a pioneer in positive-pressure tubing for holding pens, Breunig has figured out how to operate his system for optimal performance. One of the biggest changes he made to the original design was to swap out the pulleys in the fan for one size smaller in order to slow down air flow.
“The air wasn’t getting out fast enough, and it was pulling too much energy and flipping out the breaker,” he learned. “One size smaller pulley made a difference on how much energy the fan was drawing.”
Nordlund had also suggested including one more fan and tube in the low-cow-traffic area in the back of the pen, and Breunig now sees how the sixth set would have been beneficial in that spot. He adds, “When you walk to the back of the holding area, there is a distinct air difference.”
To compensate, he re-mounted one of the previously used fans onto the side of the holding area, blowing toward the breezeway.
As for repairs, so far Breunig has only replaced one tube following an incident with the crowd gate. He prevents further damage by routinely turning the system on throughout the year to blow out any moisture sitting inside the tubes that may freeze and cause it to sag dangerously close to the gate.
Flipping on the fans periodically is a simple and effective way to prevent moisture from collecting and freezing in the system.
Breunig acknowledges that retrofits like his are more likely to face challenges with the proximity of the tubes to the crowd gate, but in newer facilities with higher ceilings, that may not be an issue.
His next project is to automate the fan system in conjunction with thermostatic control curtains around the holding area.
The little things make a difference
Breunig sees the investment in heat abatement and ventilation to be worthwhile. In his mind, it is one of many efforts he can make to keep his cows performing at a high level.
“I’m not trying to be an 80-pound herd; I’m trying to be a 110-pound herd,” Breunig says. “Those little things can make a 2- to 3-pound difference.” Another “little thing” he strives for is to reduce the time cows spend in the holding area waiting to be milked, with the goal of keeping it under one hour.
With the positive-pressure tube system, along with sprinklers and rubber on a portion of the floor, the holding area at Mystic Valley Dairy is certainly now a more pleasant place for cows. Breunig concludes, “We invest money into making it a healthy and comfortable environment and do whatever we can to keep cows cool while they are there.” 
PHOTO 1: Five positive-pressure tubes (right) run the width of the holding pen at Mystic Valley Dairy.
PHOTO 2: Mitch Breunig was looking for a better way to keep his high-producing 400-cow herd cool while they waited in the holding area. Photos by Ray Merritt.
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Peggy Coffeen
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- Progressive Dairyman
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