SETTING CHARACTERISTICS OF FEEDLOT CATTLE FECES AND MANURE

Increased community awareness has created pressure on feedlots to impr ove their environmental performance. Australian feedlot sedimentation systems are failing currently use empirical designs. These designs cou ld be improved by basing them on settling characteristics of Australia n feedlot manure. Settling velocity distributions of fresh feces and p en manure were measured using a settling column. We found that settlin g velocities of fresh feces are similar to those of pen manure and tha t rations that used barley or greater proportions of roughage had smal ler components of slow-settling solids. All samples showed distinct fa st and slow settling components. Some 35 to 75% of the material settle d quickly and the remainder settled so slowly that it is not practical to design sedimentation systems to retain it. The data suggest that s edimentation system design should use a maximum settling velocity of 0 .003 m/s.