Solid front and rear panels on calf pens may protect calves from the cold, but they also limit ventilation in naturally ventilated calf barns.

According to research in the October 2006 Journal of Dairy Science, solid front and rear panels allowed high levels of airborne bacteria to accumulate in calf pens in naturally ventilated barns during the winter. In fact, the average pen airborne bacterial count from 13 naturally ventilated calf barns was 112,280 colony-forming units (cfu) per cubic meter of air. Overall, bacterial counts ranged from 29,000 to more than 326,000 cfu per cubic meter of air. “The high air count was associated with poorer calf (respiratory) health,” says Ken Nordlund, veterinarian at the University of Wisconsin.

Instead of enclosing and covering the pen to protect against drafts, supply deep-straw bedding in which the calf can “nest.”

“Nesting means that you cannot see the calf’s legs when it lies down in the bedding,” Nordlund says. Keep a solid panel between each calf, though, as this reduces respiratory disease.