Net $100 per cow more. That's the bottom line in cross-ventilated barn economics, says Kevin Dhuyvetter, an agricultural economist with Kansas State University.
Though cross-vent barns are no less costly to build and are more expensive to operate and maintain, a higher return per cow than a naturally ventilated barn is entirely possible. "We don't have a lot of side-by-side comparisons [because the barns are so new], but the economics are worth looking at,” Dhuyvetter says.
First and foremost, you won't save capital cost building cross-vent barns. Initially that was the thought, 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) saves on roof sheeting.
But the low pitch (½/12) means steel girders replace wood trusses to carry the roof load. Ceiling and walls must be insulated to prevent condensation. Water-cooling pads are needed on the inlet side of the barn and baffles are needed inside to keep air movement down over beds.
The other myth is that cross-vents require more fan power for ventilation. Surprisingly, they require about the same amount of fan capacity per cow as a naturally ventilated barn that is equipped for summer cooling.
In his analysis, Dhuyvetter assumed that the facilities—natural or cross-vent—cost $4,650 per cow to build. He assumed a 20-year life, 10% salvage value and 8% interest.
He calculated that the cross-vents cost more to operate because some fans must run 24/7 all year long. In winter, 10% to 20% of the fans must run, even when temperatures dip well below zero, to ensure a continual fresh air supply.
At 6¢/kwh, Dhuyvetter estimates, 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 that cross-vents provide is a more consistent environment year-round. The design keeps barns warmer in winter and knocks 10¢ªF to 20¢ªF off the hottest days of the year. Feed efficiency improves 3% on average since cows don't spend 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. Enclosed cross-vents can also feature long-day lighting. All told, cross-vent barns should push a 23,000-lb. herd up to 24,000 lb.
"Bottom line: I can make about $115 more per cow or produce milk for about 50¢/cwt. less,” Dhuyvetter says. "At any level of production, return on assets is always better because of better feed efficiency.”
The biggest wild card: Cross-vent barns are different. As in mechanically ventilated tiestall barns, managing cow comfort becomes fan dependent—and all that entails.
Click here to read about economic considerations at the Kansas State University website.
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