Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Ranching with sable antelope (Hippotragus niger niger) in South Africa

Auteur : Shepstone, Craig Alan

Université de soutenance : Stellenbosch University

Grade : Master of Science ( MScAgric) 2022

Résumé partiel
This research focuses on aspects not currently known but essential to ranch with sable antelope (Hippotragus niger niger) successfully. This includes determining the metabolizable energy requirements, horn growth traits and how supplemental nutrition affects reproduction and horn growth on sable antelope ranched in South Africa. An investigation into the methodologies presently employed determining carrying capacity of wildlife species illustrates that the large animal unit, grazing unit, and browsing unit methods only use metabolic weight as a factor to determine the energy requirements of game where the large stock unit method uses both metabolic weight and the energy requirements of the animal at a specific well defined physiological production state. The metabolizable energy requirement per day was regressed with weight (kg) using a log-log transformation of the herbivore species to model the suitability of the large animal unit method for defining/determining the metabolizable energy requirements of game. The resulting equations were used to model and compare the calculated metabolizable energy and large stock unit values to the published metabolizable energy and large stock unit values. The physiological production states analysed included 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. Six out of the seven categories have values higher than 0.75 with R 2 values of >0.99, the exception being calf/lamb data with the value of 0.742 with a R2 = 0.97. These results indicate that metabolic weight is neither conceptually correct nor sufficiently accurate to calculate metabolizable energy 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 provides a more accurate method for determining the metabolizable energy requirements and dry matter intake values for sable antelope and other game species. A study into horn growth characteristics (traits), horn length, basal circumference, and the number of horn rings of sable antelope in South Africa was conducted to investigate the environmental effects of sex, calving year and season on horn development for animals up to 50 months of age. Horn growth characteristics/traits within the age categories of 0-15 months, 15.1- 36 months, 36.1-50 months were analysed.

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