Many calf barns rely on natural ventilation to provide clean, fresh air to calf pens. But, as the weather cools down and winter approaches, there can be a tendency to close the doors, windows and curtains on the calf barn in an effort to reduce drafts. Preventing cold air from blowing on calves can help keep calves warm, but when buildings are closed proper air exchange to keep calves healthy through the winter months can be prohibited.

“If you fail to get good ventilation or adequate air exchange in calf barns, you get a build-up of dust, pathogens and moisture in the air,” says Gary Geisler, calf and heifer specialist with Purina Animal Nutrition. “A build-up of ammonia can occur and cause irritation to the respiratory system of calves.”

Geisler cautions that if close attention is not paid to ventilation, a breakout of pneumonia or another respiratory disease could occur. Symptoms that might indicate a respiratory infection include: coughing, nasal discharge and watery eyes.

The goal for wintertime ventilation is to have a minimum of four interior air exchanges per hour in calf barns, which can be provided by a positive pressure ventilation system. A well-designed system will deliver fresh air to the immediate environment of the calf without creating a draft.

“A positive pressure ventilation system supplies fresh, outside air into the calf barn and distributes the air evenly throughout the barn,” says Geisler. “In barns with individual calf pens this is especially important because the system is designed to move air into “dead spots” – areas where the air may be stagnant, such as between solid calf pen panels. Stagnant air can harbor airborne pathogens.”

Positive pressure ventilation systems when designed properly can run 24 hours per day, even in cold weather. While positive pressure ventilation systems can be a great solution for providing air exchange throughout your barn, Geisler cautions that these systems are “not one size fits all.”

“Positive pressure ventilation systems should be designed based on the number of calves, size of building, dimensions of the barn, layout of the calf pens and more,” says Geisler. “It takes precise planning to achieve even distribution of air throughout the facility, but no drafts.”

The Dairyland Initiative, a University of Wisconsin School of Veterinary Medicine outreach program, provides resources that can assist dairy producers in properly planning a ventilation system. A list of trained designed consultants throughout the U.S., Canada and beyond can be found online.