What does your pigs’ environment have to do with your herd’s production and health? Everything.

Barn temperature, temperature fluctuations, humidity, drafts and gas levels all have documented roles on their ability to impact swine health, says Michael Eisenmenger, DVM, Swine Vet Center in St. Peter, Minn.

Those elements have the ability to affect how disease pathogens spread through a barn; how long pathogens survive in the pigs’ environment; pathogen exposure levels in the barn; and the concurrent stress levels that pigs face.

Eisenmenger looks at the following specific environmental factors that can affect swine disease in a production system:

Humidity can be an excellent tool to monitor minimum ventilation rates in cool months when the facility’s ventilation system is attempting to run conservatively. 

You can measure relative humidity in a barn with an inexpensive thermohydrometer, but the more expensive versions are more accurate, more durable and can be read quicker. He points out that the relative-humidity probes that hang in the barn and are operated through the controllers tend to be inaccurate and short-lived in commercial production settings.

Goals for humidity levels in swine confinement buildings should be 50 percent to 70 percent.

The barn’s ambient temperature depends on many factors. In a typical full-slat, double-curtain or tunnel-ventilated barn, for example, temperature curves normally range from 88°F to 62°F in the wean-to-finish phase.

Hanging a high/low thermometer in the room is a way to measure temperature because you can go to specific areas within the barn and check the high/low temperature range a that specific location. A room-temperature probe also is important because this device drives the ventilation controller to run heaters, fans and curtains.

A temperature recording device offers a more detailed look. Eisenmenger has used a controller with an external stainless-steel probe to record temperatures.

“The monitor has an external start and stop button so you can program

it before getting to the barn, and then turn it on just before entering,” he says. “It can be completely submersed or wiped off with a disinfectant to accommodate biosecurity protocols between pig buildings.”

In terms of managing temperature fluctuations, Eisenmenger suggests checking the following areas:

  • Curtain settings. Because different controllers manage curtains in a variety of ways, it is critical that you develop a thorough understanding of each controller systems’ capabilities and limitations.
  • Keep curtains up as long as possible. “This is the most important step,” he contends. “The more cubic-feet-per-minute capacity per pig in the barn, the higher the outside temperature can be before the curtain needs to make a move.”

    He recommends that regular checks to ensure that all fans are operational, that all fans and shutters are clean, and that air inlets are set so that they can open. Also ensure that there are enough air inlets to match the cubic feet per minute total of the barn (for example, total cubic feet per minute divided by 800 feet per minute equals the size of the square feet per inlet needed) and enough soffit-inlet space (total barn cubic feet per minute divided by 500 equals the square feet needed.)

  • Bandwidth on Stage 1 and Stage 2 fans are set too tight. Bandwidth on a particular stage on a controller relies on the number of cubic feet per minute per pig needed within that stage. In general, the greater the cubic feet per minute needed on an individual stage, the wider the bandwidth should be set.
  • Incorrect probe placement. A probe placed in front of a heater reads the room as being too warm, which will cause fans to ramp up, leading to increased LP-gas usage. A probe placed in front of an inlet will read the room as too cool, causing the heater to run.

    Incorrect air-inlet settings can cause a barn to fluctuate in two ways. “Not having enough inlets to meet the barn’s total fan capacity will cause curtains to come down sooner, potentially leading to large temperature fluctuations,” notes Eisenmenger.

    Attic inlets (soffit inlets) that are plugged (made of the wrong material, such as residential material versus bird screen) will cause negative pressure within the room to get too high, causing curtains to be sucked tight against the barn.

Combined or alone, these environmental factors can affect your pigs’ health and your profitability.