Abstract

SHEPSTONE, C.A. et al. Metabolizable energy requirements, dry matter intake and feed selection of sable antelope (Hippotragus niger). S. Afr. j. anim. sci. [online]. 2022, vol.52, n.3, pp.326-338. ISSN 2221-4062.  https://doi.org/10.4314/sajas.v52i3.8.

The large animal unit, grazing unit, and browsing unit methods for determining carrying capacity of wildlife use only metabolic weight as a factor to determine the energy requirements of game, whereas the large stock unit method uses metabolic weight and energy requirements of the animal at a specific well-defined physiological production stages. The metabolizable energy requirement in megajoules per day (MJ ME/day) was regressed on weight in kg using a log-log transformation to ascertain whether the large animal unit method was suitable for defining and determining the ME requirements of game. The resulting equations were used to compare the calculated ME and large stock unit values with the published values. Six of the seven categories had values higher than 0.75 with R² values of >0.99, the exception being calf/lamb data with a value of 0.742 with an R² = 0.97. The physiological production stages that were analysed were calf/lamb, young dry cow/ewe, mature dry cow/ewe, young cow/ewe with calf/lamb, mature cow/ewe with calf/lamb, young bull/ram, and mature bull/ram. These results indicated that metabolic weight was neither conceptually correct nor sufficiently accurate to calculate ME requirements for game, confirming the acceptance of the alternative hypothesis. Therefore, the large animal unit (metabolic weight method) cannot replace the large stock unit (metabolizable energy method). The derived log-log transformation equation provided a more accurate method for determining the metabolizable energy requirements and dry matter intake values for sable antelope (Hippotragus niger) and other game species.

Keywords : browsing unit; carrying capacity; grazing unit; large animal unit; large stock unit; stocking rate; wildlife ranching.

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