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Animal Safety and Positive Pressure Ventilation


Britt Roman

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Third-generation farmers, and owners of Iowa Select Farms, Jeff and Deb Hansen, started with humble roots in 1976, farrowing just three sows. Through passion and hard work, Iowa Select Farms was born and has grown steadily to become the fourth-largest pork producer in the United States.

Screen Shot 2022-01-26 at 9.44.43 AMFrom 2013 to 2017, Iowa Select Farms needed to create 30 filtered positive pressure sow farms and 10 positive pressure gilt developer units through a combination of remodeling and building new barns. At less than half the cost of building new barns completely, retrofitting some of their existing structures with new equipment made the smart economical choice for Iowa Select.

Proactive PRRS Mitigation

Porcine Reproductive and Respiratory Syndrome (or PRRS) remains a serious concern for all swine operations and can cause significant operational and financial stress. Iowa Select Farms is proactive in their pursuit to mitigate PRRS; what makes them unique is their dedication to innovation. They are forward-thinking, open to technological innovations and use scientifically-sound principals in all stages of pork production. Because PRRS impacts both the sow and piglet, Iowa Select works hard to ensure the 242,500 sows across their 48 sow farms are protected from an outbreak in full measure.

Enter, Munters. 

Munters has been designing and refining filtered swine facility ventilation for many years working with some of the top hog producers to create the Positive Pressure Ventilation Design. The latest innovation in livestock ventilation incorporates air filters, evaporative cooling with CELdek, Munters Drive VX51 Fans, BI28 Inlets, and actuated outlet walls – all carefully engineered to create a Positive Pressure Ventilation System to protect animals from outside contaminants. Today, over 300,000 sows are currently using this system.

Additionally, all of the barns use Munters Drive, an Electronically Communicated (EC) motor and drive solution that reduces electrical usage and maintenance, helping to reduce their carbon footprint, save money, and usher in a greener approach to ventilation.

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How it works

Outdoor unfiltered ambient temperature air passes through the filter wall, removing airborne pathogens. Then the air hits an evaporative cooling wall to cool warm summer air. Munters Drive VX51 fans precisely pressurize the attic with filtered and cooled air. As the building becomes pressurized, the BI28 Inlets allow the precise amount of air to maintain temperature and airflow. Munters backdraft shutters prevent pressure drops and backdrafts in windy conditions. An actuator with pipe drive systems adjust curtain openings to maintain constant pressure and provide an outlet for metabolic gases.

This top-down ventilation ensures condensation is reduced to help prevent building rot and unlike a negative pressure systems where even the smallest air leak can let unfiltered air in, a positive pressure barn is continually pushing air out. Even small cracks don’t impact the filtered air. Munters Drive is made to run at higher static pressures than typical agricultural fans without additional electrical usage. The infinite variable speed allows them to fine-tune both the temperature and pressure in the barns. Munters Drive is programmed to run at a constant speed with no loss from belt wear, ensuring proper airflow that maintains attic pressure with minimal maintenance.

The Result

Iowa Select estimates that the Munters design pays for itself entirely by preventing two outbreaks. Additionally, they estimate an eight-fold decrease in PRRS outbreaks. In 2017, less than two years after the farm’s positive pressure filtration remodel was complete, their pigs per sow per year had jumped 25 percent and pre-wean mortality dropped 19 percent. What’s more, their employees have reported experiencing a healthier and more satisfactory work environment. They also have a healthier herd that is easier to manage. Anyone who knows the Iowa Select Farms crew knows how important their staff and community are. Their passion is greater than the day in-day out of caring for their herd.

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This article first appeared in the 2021/22 Modern Producer magazine and was contributed by Britt Roman and the Munter Corporation. 


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