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Open Feedlots – Introduction

Iowa’s open feedlots are places where animals are kept in unroofed or partially roofed areas. To be considered an open feedlot, animals are fed and maintained in pens for at least 45 days in a one-year period.  Unlike animals on pasture, manure from the animals is concentrated and the ground is bare of vegetation.

Minimum Requirements: Open feedlot producers are required to manage manure, process wastewater, settleable solids and effluent from the feedlot according to the following:
  • Remove all settleable solids from the effluent prior to discharge into a water of the state and ensure that the discharge does not cause a water quality violation.
  • Prevent any direct discharges into publicly owned lakes, known sinkholes or agricultural drainage wells.
  • Land apply all effluent in a way that will not cause pollution of surface or groundwater, including meeting separation distances from environmentally sensitive areas. Additional requirements apply for concentrated animal feeding operations (large and medium CAFOs), including the possible need for a national pollutant discharge elimination system (NPDES) permit.
  • A nutrient management plan (NMP) is required for any open feedlot with an NPDES permit or capacity of 1,000 animal units (e.g., 1,000 head of cattle or 750 mature dairy cows) or more at any one time.
  • Stockpiling of settleable solids or manure solids scraped from the feedlot must comply with state law.  

Report Spills: Producers must also report spills and manure discharges to the DNR’s 24-hour spill line at 515-281-8694. Contact the local police department or sheriff if the release involves a public roadway and public safety could be threatened. Spills can occur as producers store, handle, transport or land apply manure, process wastewater, open feedlot effluent or settleable solids. The discharge might be due to equipment breakdown, storage structure breach or runoff. All of these must be reported to the DNR as soon as possible but not later than 6 hours after the onset or discovery of a release.

The DNR’s field specialists have extensive experience with manure spills and discharges. The sooner a producer calls in a spill, overflow or discharge the more likely the DNR specialist can help the producer analyze the situation – helping to minimize additional runoff and prevent further pollution.  

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