Winter weather can cause many problems for dairy farmers depending on where they are located and the conditions they experience. One of the biggest challenges dairy farmers face in the winter is when their barns freeze. To an extent, cows can handle cold environments if they are kept dry and if air speeds are not too strong. However, if barns begin to freeze, it can have a serious impact on the herd’s health and productivity. Issues such as reduced dry matter intake (DMI), frostbite, mastitis, pneumonia and cold stress can occur. While these freeze-related issues can be difficult to manage, ventilation can help alleviate them. As we transition from summer to winter, is your ventilation system ready for the coming freezing temperatures?
There are many recommendations on how to mitigate winter freeze conditions, and we recommend using ventilation as a preventative measure. Each ventilation system will look different based on the needs of your herd and barn. Systems can be made for cross, tunnel, natural or hybrid barns, and the type of barn you have will impact how you utilize ventilation in the winter months. If you are looking for more information on how these different kinds of fans work together to make an efficient ventilation system, there are a plethora of articles you can find from Progressive Dairy, Dairyland Initiative and others.
Here are some components of ventilation systems that have worked for us and our customers when combined.
- Inlet fans (injection fans): Inlets bring fresh air into the building for circulation fans to distribute.
- Circulation fans (high-volume low-speed or HVLS, panel, louvered): Circulation fans move present and incoming air throughout the barn so that water does not stand still and freeze. HVLS and panel fans work best for circulating air, while louvered fans work best for directing dry air to the cow level.
- Exhaust fans: These fans remove dirty, humid air, which supports circulation fans to more efficiently move air throughout the facility.
These three different styles of fans work well together to move air and prevent freezing in barns.
Preventative measures for common winter freeze issues
Variable frequency drive
A variable frequency drive is a useful tool that can help make your ventilation system easy to operate. Paired with an environmental control system, it can increase or decrease fan speeds depending on the building’s temperature, ensuring the herd is always taken care of and freezing is prevented. The variable frequency drive will operate the fans to produce the correct amount of airflow for the current environmental stage, improving airflow distribution and decreasing energy usage when compared to similar-sized single-speed fans.
Frozen alleys and beds
To mitigate frozen alleys and beds, keep temperatures above 32°F (0°C). You can achieve this by using inlet (also called injection) fans with internal deflectors. The inlet fans with the deflectors bring in fresh air aimed high, so it is tempered when it reaches cow level (below 6 feet or about 2 meters). Combining that tempered air with the heat cows produce can help prevent alleys and beds from freezing. We recommend using injection fans because they are less susceptible to inconsistent pressures and can reliably provide targeted fresh air.
Humidity and dew points
Use exhaust fans to remove moisture from the building. It is important to not pull out too much air or an excessive amount of cold air will be pulled in. Remember to balance the air exchange with the needs of the barn to work properly. It is best to run your exhaust fans at 60%-65% power to ensure they are running efficiently. Keep your dew points lower than the air temperature to prevent condensation and freezing. It is important to keep in mind that when temperatures outside are extremely cold, the relative humidity is high.
Frozen curtains
Curtains that open from the bottom can be tricky to deal with in the winter months because they are more likely to be stuck in a snowbank. For this issue, having a split curtain works best so you can open the curtain from the top. To avoid freezing or jamming, it is best to avoid using curtains entirely until the outside temperature is at least 32°F (0°C) or higher.
Short-circuiting
Avoid short-circuiting by using inlet fans to bring in fresh air and balance static pressure. This reduces air from taking the path of least resistance and gives the environment more adequate conditions for directed ventilation.
Freeze
If you notice certain areas are freezing, double-check the inlet airspeeds and direction to ensure we are bringing in air at 800 feet per minute or 4 meters per second. This will help the outside air enter high and mix with the heated air within the barn before reaching the lanes and stalls.
Freezing prevention encourages an animal-centered environment
Dr. Michael Wolf, consulting veterinarian for VES-Artex, says these anti-freezing ventilation strategies are helping create an animal-centered environment. “We are doing anything we can to make that quality of life in her living zone [less than 6 feet, or 2 meters] better through targeted approaches,” Wolf says.
One of the most important things to consider is cow comfort and its impact on production, conception and profitability. Cold stress, illnesses and other issues reduce production rates. To minimize the various freeze-related issues, pay attention to your herd’s environment – things such as keeping their bedding dry, maintaining the humidity inside the barn and making sure the entering air is tempered before reaching the cows. The best way to avoid any issues is to reduce freezing throughout the barn during the winter months, which can be accomplished by using preventative ventilation strategies.
Harsh winter conditions can make dairy farming more difficult, but it is possible to prevent freezing with these recommended ventilation strategies. If a barn does not have a proper ventilation system in place, it is more likely that freeze-related issues may start to occur and, in return, have a negative impact on your herd’s comfort and profits. Ventilation plays a key role not only in winter but during all seasons. For year-round cow comfort and safety, pay attention to your ventilation strategies and system.
