The rate of consumption of bush and grass by goats in a representative acacia karroo savanna community in the Eastern Cape

Abstract

Consumption of browse and grass in a representative Acacia karroo savanna community was measured. Acacia karroo was preferred to grass. It was selected almost exclusively when available at high leaf densities. Grass was consumed in significant amounts only when approximately 50 % of the available A. karroo leaf had been consumed. Maximum daily intake was 78 g.W^−0,75 _kg.day⁻¹ and decreased with decreasing amount of browse on offer. When approximately 90 % of the available A. karroo leaf had been removed, the goats had consumed only 30 % of the available grass. Total intake of browse plus grass was lower during the period when the goats changed from consuming mostly A. karroo to consuming mostly grass. Goats did not appear to select a diet according to their nutritional needs, as judged by feeding tables, when this was possible. This may be due to protein indigestibility caused by tannin complexing by A. karroo, luxury consumption of A. karroo as a favoured food, an adaptation by goats to use browse more efficiently than grass, or differences in palatability between A. karroo and grass.