Nordlund has worked with several large dairies that have installed narrow, naturally ventilated barns, 35 feet wide or less, with a single tube ventilating a single row of calf pens. They use multiple all-in, all-out barns, which allow uniform age groups in each barn and thorough cleaning between uses. For wider barns, he recommends one tube for each 25 to 30 feet of width.
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Over the past five years, Nordlund has been involved in training more than 200 people in five countries to design and install these systems, and he says more than 2,000 barns have been fitted with the tubes. In some cases, dairies retrofitted these systems into tie-stall barns re-purposed as calf barns and into open-front heifer barns, seeing improvements in health even though ventilation seemed adequate prior to installing the tubes.
Nordlund’s studies have shown three factors associated with reduced incidence of bovine respiratory disease (BRD) in calf barns: low airborne bacterial counts, solid panels between pens and deep bedding for insulation. Supplementing natural ventilation with positive-pressure tubes has resulted in 50 to 70 percent reductions in BRD in calf barns in many cases, achieving health similar to outdoor hutches.
One operation that made the transition is Double S Dairy, Markesan, Wis. Herd manager Dan Smits recalls the dairy built new, naturally ventilated calf barns several years ago. In these narrow barns, open to the south, each has a single row of individual calf pens. After a year of use, the dairy’s management team decided the barns did not consistently provide optimum ventilation and worked with Nordlund to install tube systems.
Smits says the dairy did not have severe problems with BRD prior to the change, but saw noticeable improvement after installing the tubes.
Meanwhile, Select Sires, Inc. worked with Nordlund in designing calf barns for the high-value seedstock bull calves that the company raises. The company built two calf barns at its Ohio facility, one for calves from 30 to 75 days of age and one for calves from 75 to 180 days. Both of the barns use tube-ventilation systems, but are set up differently based on the requirements of the age groups.
The barn for young calves is 36 feet wide and 140 feet long, with one ventilation tube down the center. Individual calf pens are 5 feet by 7 feet and are positioned in two rows, each 5 feet from the side wall on either side of the barn to avoid down-drafts from the eaves. The ventilation tube is located within the barn’s roof trusses, 12 feet above the floor.