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Wintertime ventilation: Cow comfort, not human convenience

Suzanne Meck Published on 31 December 2015
dairy cows

Cold temperatures can have many effects on a dairy farm. Frozen manure or waterers and frigid temperatures for workers can be management nightmares.

Despite the winter weather, completely closing up the barn can have a very negative impact on the herd.



Out with the old, in with the new

Cows need fresh, clean air delivered year-round. Wintertime ventilation emphasizes keeping dry air moving throughout the barn. Dairy cows are heat-producers, each breathing out 3 to 4 gallons of water per day. Is your barn effectively moving that hot, moist air out and replacing it with the clean air your cows need to stay healthy and productive?

The temperature inside the barn should not be more than 10ºF different than the temperature outside. This means that, depending on the climate, freezing inside the barn is a possibility. Alternative methods of manure handling and heaters in waterers are much better options to address these issues than closing up the barn.

Some farms in colder climates have chosen to insulate their barns. Insulated barns can maintain a significantly warmer temperature (30 to 40ºF higher than outside temperature) and still deliver a healthy environment; however, they do take more planning to ensure adequate airflow.

Both mechanically and naturally ventilated barns need to take ventilation precautions in the winter. A combination of barn design, construction and mechanics (fans) often comes together to deliver the basic keys of successful winter ventilation:

  1. Outlet/exhaust fans
  2. Ample air intake
  3. Automation

1. Outlet/exhaust fans

In mechanically ventilated barns, continuous fans should be on year-round to help exchange air. Other fans can be put on thermostats in order to add ventilation as the temperature increases. Routine maintenance is vital to keeping these systems working properly.


Ensure fan blades and louvres are dust-free so they don’t inhibit airflow. In naturally ventilated barns, ridge vents or chimneys should remain at least partially open.

They can be closed slightly during severe inclement weather to keep out high gusts and snow but should be opened again when the weather returns to more mild conditions.

2. Ample air intake

While the exhaust units of barns are important, the air inlets are even more important. Fresh air needs to enter to replace the stale air in the barn.

Check that sufficient inlet is present and free from obstructions. Inlets should allow fresh air to reach all areas without creating dead spots. There are a variety of inlets that you can choose from depending on your facility.

Adjustable curtain side and end walls can be opened to allow air intake during winter months. If you haven’t already, take time to look for holes or tears in your curtain.

The goal is to control ventilation and maintain a nearly ideal climate, not to create unintentional drafts from poor maintenance. No matter what kind of inlet you are using, make sure it is large enough to allow adequate air to enter based on the size of your building.


3. Automation

There are many options to automate and help manage the ventilation of your facility. Computerized controls can monitor the outside temperature, wind speed and precipitation to automatically adjust curtains, vents and fans based on current conditions.

By using these controls and other precision management, the cows’ comfort no longer depends on someone remembering to make adjustments.

Other innovations in technology, such as variable-speed fans and variable-frequency drive motors, provide further refinement to delivering the exact amount of air required to every animal.

Automation takes the guesswork out of predicting weather fluctuations and provides needed relief during unexpected temperature spikes. The end result is a more consistent environment for the cow based on her needs.

When it goes wrong …

What happens if your winter ventilation isn’t up to snuff? Without space to escape, naturally occurring gases will build up. These gases can corrode the barn structure over time. Typically, an ammonia smell is an indicator of insufficient airflow. The air should smell “fresh” and have a “light” quality, not be heavy or have a foul aroma.

Another sign of poor ventilation is condensation on the walls and ceiling of the barn, resulting from humidity. In some cases, condensation is so heavy that it runs down the walls, as if your barn is “sweating.” This condensation can also freeze, causing frost on the inside of the barn.

Not only will poor air quality deteriorate your barn faster, it will also create health issues in your cows. Pneumonia and other respiratory problems are often higher in the winter due to the challenge of effective ventilation. In addition, poor air quality affects the overall health of the cow, leading to reduced milk production.

Remember, it isn’t how you feel that matters. The climate in your barn should be tailored to your cows’ needs rather than your comfort or management convenience. Winter’s low temperatures are closer to a cow’s ideal comfort zone.

This is her opportunity to recover from last summer’s heat and prepare for the year ahead. By providing a healthy, clean environment, your cows can have a greater chance of reaching their full potential.  PD

Suzanne Meck is an industry professional and freelance writer based in Wyomissing, Pennsylvania.

References omitted due to space but are available upon request. Click here to email an editor.

PHOTO: A dairy cow breathes out 3 to 4 gallons of water each day. During the wintertime, it is important to have a ventilation system that effectively removes this warm, moist air. Photo by Peggy Coffeen.