|Jim Dickrell |
Dhuyvetter is an agricultural economist with Kansas State University. K-State has been a leader in developing the new cross-vent barns. By default, Dhuyvetter was called upon by John Smith and Joe Harner to run the numbers.
Smith is the K-State dairy specialist who sketched out the first cross-vent barn on a, um, bar napkin three or four years ago. Harner is the K-State ag engineer who had done a lot of ventilation design work to make these barns cow comfort heaven. (Click here for a primer on cross-vent barns.
What Dhuyvetter found caused about 130 folks attending a two-day conference and tour of cross-vent barns sit up and take notice in Sioux Falls last week. Though the barns are no less costly to build and are more expensive to operate and maintain, $100 net return per cow over a naturally-ventilated barn is entirely within the range of possibilities.
"We don't have a lot of side-by-side comparisons [because the barns are so new,] but the economics are worth looking at,” says Dhuyvetter.
First and foremost, you won't save capital cost building cross-vent barns. Initially, that was the thought—especially at larger herd sizes because more cows can be brought under one roof with a smaller total land-use footprint. Plus the low profile building (you don't need the 4/12 pitch for natural ventilation) should save on roof sheeting.
But the low pitch, ½/12, means steel girders replace wood trusses to carry the roof load. Ceilings and walls need to be insulated to prevent condensation. Plus, water-cooling pads are needed on the inlet-side of the building, and walls of baffles are needed inside to keep air movement down over the cow beds.
The other misnomer is that cross vents require much more fan power for ventilation. Surprisingly, the cross vent barns require about the same amount of fan capacity per cow as a naturally-ventilated barn properly equipped for summer cooling.
So in his analysis, Dhuyvetter assumed the facilities—whether naturally- or cross-ventilated—cost $4,650 per cow to build. He assumed a 20-year life, 10% salvage value and 8% interest.
He also calculated that the cross vents cost more to operate because some fans must run 24 hours per day seven days per week 365 days per year. In winter, that means 10% to 20% of the fans must run, even when temperatures dip well below zero in North Dakota, to ensure a continual fresh air supply. At 6¢/kwh, Dhuyvetter estimates the cross-vent barns use about 50% more electricity per year than naturally-ventilated barns. "But even if electricity doubles, electricity costs jump just $23/cow/year,” he says.
The big benefit to cross-vent barns is they provide a more consistent environment year around. They can keep barns warmer in winter and knock anywhere from 10¢ª to 20¢ªF off the hottest days of the year. By doing so, Smith and Dhuyvetter say feed efficiency will improve 3% on average since cows won't spend quite as much feed keeping warm in winter or cool in summer.
If cows keep eating in summer, they should breed back better, average less days in milk and be less lame. And with the enclosed cross-vent barns, long-day lighting can also be achieved. Taken together, cross vent barns should push a 23,000-lb herd up to 24,000.
"Bottomline: I'm making about $115 more per cow or I can produce milk for about 50¢/cwt less,” says Dhuyvetter. "And at any level of production, return on assets is always better with the cross-ventilated barns because of better feed efficiency.”
The biggest wild card: Cross-vent barns are different. Like mechanically-ventilated tie stall barns, managing cow comfort becomes fan dependent—and all that entails. Dhuyvetter's question: Are you up to it?
Jim Dickrell is editor of Dairy Today. You can reach him via e-mail at firstname.lastname@example.org.