Settling Characteristics of Feedlot Cattle Feces and Manure

Abstract

Increased community awareness has created pressure on feedlots to improve their environmental performance. Australian feedlot sedimentation systems which are failing currently use empirical designs. These designs could be improved by basing them on settling characteristics of Australian feedlot manure. Settling velocity distributions of fresh feces and pen manure were measured using a settling column. We found that settling velocities of fresh feces are similar to those of pen manure and that rations that used barley or greater proportions of roughage had smaller components of slow-settling solids. All samples showed distinct fast and slow settling components. Some 35 to 75% of the material settled quickly and the remainder settled so slowly that it is not practical to design sedimentation systems to retain it. The data suggest that sedimentation system design should use a maximum settling velocity of 0.003 m/s.