A Concept of Rate of Food Passage Through the Gastro-Intestinal Tract

Data are presented which indicate that flow of ingesta through the animal follows an exponential relation. A model based on a hydraulic flow through two volumes in which complete mixing takes place is proposed. The data indicate that with the rabbit a single volume model is adequate and that a single half time is sufficient to describe the flow of feed residues. Data from previously published work by Balch are presented to support the premise that in the ruminant a two volume model describes the observed data and that two half times are sufficient to describe the flow of feed residues in the ruminant.