Estimating Percentage Dry Weight in Diets Using a Microscopic Technique

Percent composition by dry weight was accurately estimated for 15 mixtures of plants that are found in the diets of some herbivores. The mixtures were sampled by recording the frequency of occurrence of each species in 100 microscope fields using 125-power magnification, converting frequency to density, and calculating relative density as an estimate of percent composition by dry weight. Dry weight percentages were predicted directly from relative density. The microscopic technique reported in this paper would be an accurate means of determining the dry-weight composition of stomach samples, esophageal samples, rumen samples, and clipped herbage.