Erin Cortus

Fall is a transition season. After crop removal, while temperatures are cool and before soil is frozen, is an opportune time to transfer manure from manure storages to the soil for next year’s crop use.

Ventilation goes hand-in-hand with manure pumping activities. However, fall weather also means large temperature and wind fluctuations are likely; and these conditions influence ventilation system management and performance.

Manure pumping safety considerations are widely published and shared, but it never hurts to share them one more time! Manure pumping includes both agitation and pumping or removal out of the barn. Agitation creates a larger disruption of the manure volume. Any disruption of stored manure promotes the release of gases like hydrogen sulfide and methane.

Develop safety protocols for your operation and make all staff aware of protocols. Place warning signs at all entrances to buildings and storage areas where manure agitation is occurring

Remove workers from the buildings. If possible, also remove animals. Also remove any ignition sources. This can include turning off electrical power to any non-ventilation equipment, and extinguishing any pilot lights or other ignition sources

Do not start agitation until manure is two-feet below the bottom of the floor slats. Never enter a building or manure storage to rescue a distressed animal or person without a properly-fitting self-contained breathing apparatus.

A ventilation strategy during manure pumping needs to be dynamic and considerate of the day-to-day temperature, wind conditions and barn type. In an ideal world, we can remove animals from barns before manure agitation and removal. However, we recognize that animal removal is not always possible. Turning off pilot lights to reduce ignition sources takes heaters offline. This is an important safety step, but in cool weather can translate to chilly conditions for the pigs. Therefore, a ventilation strategy also needs to consider the stage of production and animal environment. Table 1 is a quick glance overview of ventilation strategies.

Manure pump-out ports are often located and accessed under pit ventilation fans. Taking ventilation fans off line reduces the ventilation capacity. These large openings can also influence air flow patterns and distribution. Air will take the path of least resistance, and air may short-circuit through these openings rather than coming through curtain wall or ceiling inlets. Covering these openings around the pumping equipment, if possible, reduces the influence the opening has on the air flow patterns in the barn and animal area.  

The guideline to remove manure at least two feet below the bottom of the floor slats before agitation is to ensure ventilation in the animal zone during agitation events. If the manure is too high, pit fan ventilation does not effectively move air from the animal zone, and increases the risk of gas exposure.

Safety is always paramount. During busy fall seasons, taking a minute to review how and why normal operating procedures, like ventilation change when moving and agitating manure, help us move more than manure safely into the next season.

The manure-handling safety considerations featured in this column and more are part of a webinar on manure safety titled, “"Manure Pit Death: A Preventable Tragedy". The webinar features a survivor’s story of a manure gas accident. Webinars are archived for future viewing by the Livestock and Poultry Environmental Learning Center. All webinars can be found at

Erin Cortus is an assistant professor and Extension engineer with the University of Minnesota. She can be reached via email at