Faecal nitrogen of browser and mixed feeder game species during different seasons

Abstract

A practical measure of assessing periods of potential nutritional stress of game species is needed in the management of these species in the Acacia karroo Riparian Thicket of the central Free State. The objectives of the study were to determine N_f concentration of four game species (browsers and mixed feeders) during different seasons, compare N_f with leaf phenology patterns, and assess whether N_f reaches levels at which body condition loss can be expected. A seasonal pattern was observed with the lowest N_f concentrations recorded during late winter, which correlated with the seasonal phenology pattern (leaf carriage) of the winter-deciduous tree species. The N_f concentrations (g N kg⁻¹ dung DM) of giraffe ranged from 18.3 (late winter) to 36.7 (summer) and that of kudu from 13.6 to 33.2. Likewise, the N_f of impala ranged from 16.9 to 28.0 and that of eland from 16.3 to 34.9. Access to evergreen woody species during the late-winter period proved to be essential in avoiding condition loss that corresponds with N_f levels below published critical levels (<16). In the absence of evergreen species, supplementary feeding is essential. Faecal nitrogen proved to be a useful indicator of seasonal trends in the nutritional status of browsing game species.

Keywords: browse resources, critical period, fecal crude protein, leaf carriage patterns