By Larry D. Jacobson, University of Minnesota Extension
With rising outside temperatures and predictions of high humidity in the coming weeks, livestock and poultry producers in Minnesota and the upper Midwest need to assure the barn ventilation systems are doing all that they can to keep animals as comfortable as possible this summer.
Here are a few items to check on:
-If the barn is fully mechanically ventilated (permanently closed curtain or solid walls), make sure the barn does not have large undesigned openings, such as open walk in doors or windows. The barn needs to have a sufficient static pressure so that when the exhaust fans are operating, there is sufficient air inlet velocity to reach animals in pens and stalls. A static pressure target level for a barn is 1/8 inch of water gauge when all exhaust fans are operating. This will produce inlet air speeds of 10-plus miles per hour, which will provide excellent barn air mixing and assist in cooling housed animals.
-Stay ahead of the heat build-up in the barn. In mechanically ventilated systems, make sure the controller's set points are low enough so summer exhaust fans and sprinklers are activated early in the day. For mature birds or animals, all the fans should be operating by the time room temperatures reach 75 degrees or even lower. Cooling systems should also be activated at mid-70s (indoor temperatures) for large mature animals and by 80 degrees for younger animals.
-For naturally ventilated or "curtain barns," sidewall curtains or vents must be opened early in the day. Controllers that open these sidewall curtains and/or ridge vents need to be set so they are in the maximum open position by the time it reaches 70 or 75 degrees in most mature livestock or poultry barns. Since outside winds are what drive the air exchange in naturally ventilated buildings, make sure there are no large obstructions such as trees, buildings or machinery that will block wind from reaching your barn's sidewall openings.
-Circulation fans in naturally and mechanically ventilated barns do not produce any barn air exchange. They simply move air over the housed animals, which will enhance animal cooling, especially if used in conjunction with sprinklers.
Besides keeping housed animals cool and comfortable, safety for animals and people is another reason to use proper ventilation in animal facilities during critical times such as manure pit pumping.
For more information on proper barn ventilation for safety, visit University of Minnesota Extension's website at www.extension.umn.edu/go/1037. An article specific to keeping dairy cows comfortable and free of heat stress can be found at www.extension.umn.edu/go/1038.
- By Larry Jacobson, agricultural engineer, University of Minnesota Extension