Abstract :
This study was conducted to determine the influence of plant chemical, physical and phenology
properties on diet selection of Nguni goats during the dry, early wet and late wet
seasons in savanna in South Africa. Diet composition was estimated by direct observation
of two different adult Nguni goats randomly selected from a herd each day for 7–8 days in
each season. Observations were made during active foraging periods for 2 h in the morning
and 1.5 h in the afternoon. The duration of each feeding bout and the species of woody
plant from which bites were cropped at each feeding station were recorded. Diet selection
was determined from the relative duration of feeding. Diet preference of each species
was expressed as an index calculated using the selection and relative abundance of woody
species. Browse species consumed by goats were sampled and analysed to determine crude
protein, neutral detergent fibre, acid detergent fibre, acid detergent lignin, condensed tannins,
cellulose and hemicellulose. Diet selection varied among the three seasons. The five
species most selected (utilised) by goats were Scutia myrtina, Acacia nilotica, Dichrostachys
cinerea, Acacia natalitia and Chromolaena odorata. S. myrtina was the most selected species
during the dry season while D. cinerea was the most selected in the wet seasons. S. myrtina
was the most preferred (highest utilisation relative to availability) in the dry and early
wet seasons while A. nilotica was most preferred in the late wet season. Spinescent species
were generally selected more than non-spinescent species in all seasons, while fine-leaf and
deciduous species were selected more than broad-leaf and evergreen ones in the wet seasons.
However, preference for broad-leaf and evergreen species increased in the early wet
season. Although plant chemistry varied across seasons, it did not explain the preference
of goats for various plant species in this study. Instead, effects of chemistry were speciesspecific.
In conclusion, this study demonstrates the importance of evergreen browse species
as a source of fodder when deciduous species are unavailable.
