Collecting, drying, and preserving feces for chemical and microhistological analysis

Abstract

Chemical and botanical analyses of feces provide information on diet quality and composition that is not easily collected directly from a grazing animal. However, fecal excreta is readily available in the pastures the animals are grazing. This study was conducted to determine the feasibility of collecting fecal samples from the pasture for chemical (nitrogen) and botanical analysis. Two experiments were conducted to determine the effects of method of drying (oven-dried vs. freeze-dried) and duration of fecal pat exposure on chemical and microhistological analyses. Concentration of nitrogen was not affected by method of drying or by duration of exposure in the field. Samples <72 hours during the winter and <24 hours during the summer may be used for nitrogen analysis. However, we recommend that samples be collected as soon as possible following defecation to reduce possible negative effects of precipitation, insect damage, and trampling. Method of drying had no significant (P<0.05) effect on percentage of identifiable fragments or subsequent forage class determination. Bleach, as a blending medium reduced pigment masking of epidermal fragments resulting in an increase in the percentage of identifiable epidermal fragments. Duration of exposure did not affect identification of most of the forage classes. The proportion of identifiable fragments, was lower during winter than summer.