Design and interpretation of nutrient digestion studies.

A variety of factors influence the results of digestion studies designed to measure ruminal disappearance of nutrients and flow of nutrients to the intestine. Feed intake, marker usage, sample collection, statistical design, and computation methods are among the factors discussed in this review. Guidelines are provided for presentation and interpretation of data from digesta flow studies. The scientific value of such studies often is limited because 1) replication, relative to expected variation, is inadequate and 2) experimental animals are not maintained under conditions similar to those used in normal production. Because studies conducted with inappropriate methods or inadequate replication are of little value and waste resources, validation of techniques is critical, and individual researchers should strive to verify their techniques.