The barn features 30-inch high sidewalls, with a roll-up curtain on either side for natural ventilation.
According to Don Monke, vice president of production operations for Select Sires, the tube-ventilation worked just as intended. If you kneel in a calf pen, you can feel the light movement of outside air from the tube at calf level. Monke purchased an anemometer to measure wind speeds at various locations and heights along the tube and confirmed the output of air is uniform and at the optimum velocity to ventilate the pens without uncomfortable drafts.
Bedding is also critical. Monke says the team uses a 6-inch base of wood shavings in each pen, with straw bedding on top as needed, depending on ambient temperature, and uses the nesting-score system based on Nordlund’s recommendations.
Calf health has been excellent, Monke says, based on average daily gains and long-term performance of the highvalue bull calves housed in the facility. The design, he says, has benefited Select Sires considerably.
Another factor influencing ventilation within individual pens is whether the pens are separated by solid or wiremesh panels, and there appears to be tradeoffs involved. Nordlund says solid panels are associated with higher levels of airborne bacteria, but mesh panels have been associated with higher incidence of BRD in some trials. Nordlund recommends that if pens are separated by a solid panel, the ends and top of the pens should be as open as possible.
At the Select Sires facility, each calf pen is open on the front and back to allow circulation through the pen, with solid panels on the sides to minimize exposure between calves. At Double S Dairy, Smits says the pens had solid side panels, with a 3-foot wall on the back and open front. The team recently replaced every other side panel with wire mesh, opening each pen to one neighboring pen. Smits says this significantly improves ventilation within the pens.
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John Maday is editor of Bovine Veterinarian, a sister publication of Dairy Herd Management.