The use of faecal analysis to predict dietary composition of wild herbivores

Abstract

Faecal samples have been proven to be valuable in determining dietary composition of wild herbivores. Results indicate that samples should only be collected from dung pads that are still wet and that show no signs of dung beetle activity or have been exposed to rain. Samples can be air dried in a ventilated room or oven dried at 60°C but care must be taken to avoid fungal growth. Dried samples can be kept in paper bags for up to 1 year before analysing . Faecal phosphorous and nitrogen can be used as indicators of the nutritive content of the veld. Faecal P concentrations can be used to predict dietary P concentrations satisfactorily, using a simple linear regression, Y= 0.32X +0.27 (r =0.66). This regression holds when impala are grazing or browsing as well as for high and low levels of intake. This equation can also be used for predicting dietary P concentrations in zebra, blue wildebeest and cattle. For prediction of dietary N concentration, both concentrations ofN and Pin the faeces should be taken into account. A multiple regression equation can be used for grazing impala at all levels of intake. In browsers tannins apparently elevate N excretion, therefore dietary N prediction may be skewed. Therefore, a regression equation using faecal Acid Detergent Insoluble Nitrogen (ADIN) and Acid Detergent Lignin (ADL) should be used to predict dietary N concentration when impala browse or for other browsers. There are different regression equations predicting dietary N concentration for grazers and browsers.