A feedlot or feedyard is a type of animal feeding operation (AFO) which is used in factory farming for finishing livestock, notably beef cattle, but also swine, horses, sheep, turkeys, chickens or ducks, prior to slaughter. Large beef feedlots are called concentrated animal feeding operations (CAFOs) in the United States^[1] and intensive livestock operations (ILOs)^[2] or confined feeding operations (CFOs) ^[3] in Canada. They may contain thousands of animals in an array of pens. Most feedlots require some type of governmental permit and must have plans in place to deal with the large amount of waste that is generated. The Environmental Protection Agency has authority under the Clean Water Act to regulate all animal feeding operations in the United States. This authority is delegated to individual states in some cases.