Wean-to-finish ventilation: Thinking outside the box

Cactus Family Farms sees energy savings, reduction of infiltration with solid-sided facilities.

Ann Hess, Content Director

September 4, 2020

6 Min Read
Cactus Family Farms

Ventilation is a passion for Matt Grimm and he firmly believes it is one of the most overlooked areas in finishing production today. That's why the wean-to-finish operations manager for Cactus Family Farms, based out of Osceola, Iowa, encourages producers to "think outside the box." To do that, he first recommends revisiting the progression of ventilation.

"I grew up in outdoor ventilation. The pigs were outside," Grimm says. "We had some sows farrowed in huts … and many times we put feeder pigs outside in snow. The pigs adapted, they did well. We had the right genetics to do that and I know there's still systems today that use this type of philosophy, but that's kind of where things started on ventilation and then they progressed to just a straight natural ventilation."

Without forced air, natural ventilation occurs through curtains or out the chimneys. The curtains control the temperature, the chimneys control the moisture. While the facilities had some more challenges controlling the ventilation, Grimm says it was still a functional ventilation system and at  low cost.

From there, many systems moved to a "power to natural" ventilation, where many of these facilities would have deep pits. Grimm says, "power to natural" refers to running the lower stages of ventilation through forced fans, and then as the barn continues to warm up, going into natural ventilation mode where the curtains would open up and at that point control the temperature within the barn.

"Some of the biggest challenges I see with these facilities today is they're too wide and we don't have stir fans to keep the air moving on hot, warm, humid days," Grimm says. "We have more infiltration areas in these barns. Examples would be gaps or holes in or around the curtains and this can cause energy inefficiency through the wintertime."

Tunnel ventilation, with large exhaust fans, is what is seen most often being constructed in the industry today, Grimm says, but he has seen modifications, such as a "power to natural" to tunnel method.

"Again, your lower stages, ventilation would be controlled through the inlets with fans, as the barn continues to warm up, then we would go ahead and use the tunnel curtains to support the additional CFMs that are being pulled through the barn in tunnel mode ," Grimm says. "By using fans to move the air across the barn, the goal is to pull more air through and more effectively cool the animals as they get bigger throughout the summertime."

Cactus Family Farms has been building solid-sided facilities, but Grimm says one of the biggest concerns people have is what happens when power is lost. The pork production system has not had any issues yet with emergencies or losing pigs. Each facility has on-site alarm systems and on-site generators that cycle at a minimum of one time per week.

"Historically, I have seen many more issues in curtain-sided barns with emergency drop systems," Grimm says. "I believe that knowing that these are in place it gives people a false sense of security, but there are many things that I have seen malfunction over the years. Some examples of this are not having the emergency drops connected, having the winch locked, the cable getting caught up in the curtain winch not allowing it to drop or even having it so cold outside that the curtain freezes to the side of the barn.”

Grimm says they are also seeing an energy savings with the solid-sided facilities — up to a 50% reduction in LP usage from what they see with their traditional tunnel-ventilated buildings.

The other thing the pork production system is seeing is a reduction in infiltration of air, Grimm says.

"Anytime you have areas of infiltration, whether it's holes in the curtains, gaps in the curtains, holes in the walls, a gap around the doors, all of that kind of stuff, these complicate what we're trying to accomplish, trying to bring air into the barn and get it in the locations that are desirable for the pigs," Grimm says. "By having a solid-sided barn, we drastically reduce the areas where we would typically see infiltration and ultimately, we're going to see a lot more consistent environment for the pigs."

With a reduction in items such as curtains, winches, pulleys, bird wire and hog panels, Grimm says there has been reduced repair and maintenance cost associated with the solid-sided facilities.

"With that, you get increased sanitation," Grimm says. "You don't have the curtain sill or the concern about getting too close to curtains because of damaging them in the washing process. We have a lot better sanitation."

The Cactus sites also do not have to do the standard four pump outs on each side of the barn, as they are not placing pump outs for ventilation, but strictly for manure removal and agitation. The solid-sided facilities also have minimum ventilation fans in the side walls versus on pit pump outs.

"It's fallacy to think that pit fans are pulling all the gases out of the pit," Grimm says. "They really only pull gas from about 10 feet around each of the fans. The most important thing is ensuring consistent, efficient air movement throughout the facility. I firmly believe that this provides an improved environment."

This type of ventilation system has also worked well in deep snow, first and foremost because it is easier to identify if they are not working as you can see that from inside the barn versus walking through snow drifts. It also makes fixing and cleaning fans a much easier task, Grimm says.

"By having our minimum ventilation fans in the walls, we will know sooner than later if they're working or not. If they're not working, 1. it's easier for us to fix them because we aren't outside in the elements, the snowbanks, the heat, whatever it may be that is not as optimal to complete the repairs," Grimm says. "No. 2, it's easier for us to clean them on a routine basis during the standard power washing process in between groups. They're going to be a heck of a lot more efficient."

Grimm says there are multiple ventilation strategies and building types to choose from and pork producers need to choose facility set-ups that work best for their operation and location.

"At the end of the day, what it comes down to is what is best for you, your system, what's best for your energy costs and how you want to run your ventilation," Grimm says. "Different areas within the country, obviously the further north you get the sidewall fans and the solid-sided barns may be a lot more effective than as you get further south, but again, that's up to your discretion."

About the Author(s)

Ann Hess

Content Director, National Hog Farmer

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