While many farms focus on checking that their ventilation systems are effectively working for their animals in the summer, an audit in the winter is also important. Courtney Halbach, outreach specialist with the Dairyland Initiative at the University of Wisconsin-Madison, joined Professional Dairy Producers' "The Dairy Signal" podcast to go over key areas to verify that ventilation systems are working correctly.

Poor ventilation will reduce air quality for animals, raise their risk for pneumonia, limit protection from extreme cold, and lead to freezing in the barn. “The goal is to have even air distribution while protecting from freezing in the barn,” shared Halbach. Fresh air in the barn will displace heat, moisture, noxious gases, and airborne pathogens.

When looking at calf facilities, airborne pathogens are a greater risk. Most bacteria, viruses, and fungi are found on dust particles or small water droplets. The higher the humidity in the barn, the smaller the moisture droplets and deeper penetration of bacteria into lungs. Halbach mentioned to make sure air outlets are functioning in calf facilities to ensure moisture can leave in the winter.

Halbach shared four key components to an effective ventilation system:

1. Sufficient air exchange to remove heat, dust, noxious gases, and moisture from barn
2. Target air speed in the animals’ resting microenvironment
3. Works well across seasons
4. Economical for the farm

In the winter, target four air changes per hour. In the summer, 40 to 60 air changes per hour is the target.

Basic cleaning and maintenance of ventilation is easily overlooked, but it is an easy way to make sure ventilation is working properly. Buildup on louvers can lower fan efficiency by 24%. Halbach recommended removing debris and buildup on fans, thermostats, and inlets as well as checking for cracks on blades, belts, and wires to make sure that your ventilation is working properly and efficiently.

Halbach also advised inspecting moisture near the roof on cold days. Streaking on boards, water dripping, or snow in the barn could be a sign that the roof needs more insulation or that air isn’t exchanging well. In cross ventilated barns, baffles should be raised to help prevent condensation in the winter. Ridge and chimney vents are an effective way to allow air out while protecting from precipitation in the barn.

To conclude, Halbach emphasized the importance of understanding how air comes in and out of your barns to make sure you are achieving the goal air exchanges. For information on building designs and benchmarks, visit the Dairyland Initiative website at https://thedairylandinitiative.vetmed.wisc.edu/.