Part 1: Proper cold weather ventilation crucial in swine facilities

Those involved in swine production know the three most important things for maintaining proper pig health are feed, water, and an optimum environment. With the looming onset of colder weather, most swine facilities will shift away from maximum ventilation settings toward minimum ventilation settings more appropriate for colder outside temperatures.

When hog barns are in minimal ventilation mode, the goal is to exchange enough air to keep the facility dry and the air fresh, while still maintaining a warm comfortable environment for the animals. At times, this can be a fine line to manage, as moving too much or too little air can have negative effects on the pigs.

Moving too much air can lead to chilling of the pigs, and may compromise the health of the group in the barn. Additionally, energy costs associated with maintaining the ambient temperature of the barn may increase, as heaters run for longer periods in an attempt to warm the large quantities of incoming cold air. Over-ventilation often is caused by oversized fans, damaged curtains or inlets, or improper setting of the ventilation control box.

Oppositely, moving too little air can lead to the buildup of moisture and potentially harmful gases within the barn, both of which can lead to compromised pig health, according to the Merck Veterinary Manual.

Under-ventilation could be the result of one of, but not limited to, the following: too few or obstructed air inlets, an insufficient amount of inlet space, or fans that perform below expectations in the lower RPM ranges utilized by some minimum ventilation systems.

According to Iowa State University, the following are recommended cold weather ventilation rates:

Housing Cold Weather Rate cfm/unit
Sow and litter 20
Nursery pig 2 – 3
Finishing pig 7– 10
Gestating sow 12

Boars and bred sows



In order to allow for proper ventilation, sufficient air inlet space must be designed into the facility. Amount of inlet space should be calculated by assuming an 800 feet per minute maximum velocity, and dividing the maximum air exchange rate in cfm by the maximum velocity, according to Larry D. Jacobson, Minnesota University agricultural engineer. Additionally, Jacobson recommends that during cold weather ventilation, the incoming air be drawn from a plenum in order to prevent wind outside the building from impacting ventilation rate.

Swine influenza and other diseases comprising the swine respiratory disease complex often are associated with reduced ventilation rates, according to Additionally, proper cleaning and disinfection of transport vehicles and facilities, along with sound herd health management are vital in order to reduce the chances of seasonal respiratory disease in swine.

This post continues in part 2.

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