Simple ventilation tips as warm weather approaches

Ventilation is key to running a successful swine operation. These tips and tricks can help you make the transition between seasons.

As winter starts to wind down, the temperature and humidity begins to increase inside livestock barns. Swine producers, in particular, need to be vigilant in the monitoring of their barn ventilation rates and air quality as the outside environment changes. There are several things to consider when looking at the ventilation inside swine production barns, such as fan stages and speeds, inlet air circulation, eaves openings, and overall controller settings.

Pit Fans

Swine barns today have up to seven stages that target an uptick in airflow using new fan(s) at various times. However, in the winter season, wall fans are typically not in use. Minimum ventilation is the predominant stage used in the winter months due to the cold and humid extremes. Typically, pit fans are used for minimum ventilation and have been working all winter as the prime ventilation source. These fans will be dirty and will need to be cleaned in the spring, to keep the airflow happening efficiently throughout the barn. If fans are extremely dirty, this has the potential to reduce fan capacity by as much as 50%.  If fans do not move enough air, they will go to the next stage of ventilation; this will decrease the overall ventilation efficiency within the barn and cause more power and electricity to be used to get the correct airflow and achieve the same CFM for the barn.

Eave Openings

Another winter ventilation concern is having fabricated coverings over the barn eaves to slow some of the cold air and precipitation.  However, after a long winter, eaves can become blocked with heavy snow, rain, and ice; which renders them ineffective.  If the eaves are not cleaned, dirt that has accumulated will block air from coming into barn when more ventilation is needed as temperatures warm up and more air is required from eave openings. Be sure the screen in the eave opening is clean and free of obstruction for airflow purposes. Screens can be easily cleaned with a broom.


Many producers and managers are under the misconception that heat or temperature is the reasoning for why barn ventilation is used.  Humidity is an equally or sometimes more important reason for having airflow and movement through a barn. Humidity extremes can cause problems in swine barns. We ventilate to remove moisture from the barn. Humidity should be checked daily; preferably in various places throughout the barn. Humidistats can easily be obtained from a hardware store or farm supply store.

It is vital to adjust the ventilation system so that relative humidity within the barn is between 60% and 70%. This range has been shown to be the best for fighting respiratory infections. When the humidity is above 70%, airborne disease organisms multiply and spread easily, increasing the severity of respiratory infection. The dusty conditions, which can be caused by humidity below 60%, will worsen the effects of respiratory disease. Dust worsens effect of ammonia gas, airborne disease organism levels increase, and respiratory infection rate increases. Adjust ventilation for humidity to stays within the 60% - 70% range for the best air quality for pigs.

Air Speed

The recommended air inlet speed in a swine barn should be 600-900 ft./min. If the air entering the room from the ceiling inlets is moving too slow, then the air will not circulate properly and will fall directly down on the pigs creating excessive drafts and disrupt the manure patterns of pigs within the pens, which could increase the spread of disease. However, if the air enters the room too fast, this will result in erratic air circulation and temperature can ultimately inconsistent drafts throughout the barn.

Air speed requirements vary by pig size and age. If pigs are less than 40 pounds, air speed should not exceed 30 ft./min. When pigs weigh from 40-240 pounds, air speed should not surpass 300 ft./min. Finally, when pigs weigh over 240 pounds; air speed should not go over 350 ft./min. A simple way to find the air speed throughout a barn is investing in an air speed meter. This device measures the air speed from inlets and at the pig level. This will help get the ventilation correct in warm months, as well as during irregular weather.


Controller Settings

Finally, looking at your controller settings is essential for every season change. For example, in winter, the ventilation should be set at 12 degrees from set point to last stage of ventilation. Conversely, in the warm weather months, the ventilation controller needs to be changed to 7 degrees from set point to last stage. If changes are not made barn will not cool properly in warm weather causing lower average daily gains. In addition, fan bandwidths on controller should be one degree between stages in summer months for pigs over 50 pounds. If your swine barn uses circulation fans, the placement of the fans where they are pointed is critical as well. Circulation fans should be set to blow straits or slightly up.  These fans should be blowing above pigs and not on them.

In conclusion, having an effective ventilation management program during transition seasons is essential for pig health and comfort, and minimizing cost. Ventilation is important for maximizing pig performance. These are just a few tips and reminders on what to look at in your barn for your ventilation system.

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