Thesis (MSc)--Stellenbosch University, 2002. / ENGLISH ABSTRACT: The purpose of this study was to evaluate the effects of age, sex, region and cropping methodology on the meat quality of impala. Forty impala were cropped during separate day and night operations at the Mara Agricultural Development Centre. Carcass pH45 (measured in M. longissimus dorsi 45 minutes post mortem) was higher in night cropped animals (6.67 ± 0.111; P<0.05) compared to the day cropped animals (6.55 ± 0.236). The ultimate carcass pH (pHu) of animals cropped at night was lower (5.39 ± 0.081; P<0.05) compared to those cropped in the day (5.45 ± 0.108). Non-linear regression analysis showed that the rate of pH decline of the night cropped animals was slower than that of the day cropped animals (P<0.05). The cooling rate of the M. longissimus dorsi was twice as fast in the night cropped group (P<0.05). Shear force values and drip losses of the night cropped animals were both lower (19.11 ± 5.675 g/mm2 and 2.93 ± 1.597% respectively; PO.OS) compared to those of day cropped animals (23.42 ± 8.128 g/mm2 and 4.15 ± 2.339%). The results indicate that nighttime cropping has a beneficial effect on certain meat quality parameters compared to daytime cropping. A second group of impala was sampled at the Musina Experimental Farm in the Limpopo Province of South Africa. Live weights of the Mara animals (50.23 ± 9.32 kg) were higher (P<0.05) than the Musina animals (44.25 ± 10.81 kg). Impala sampled at Mara had significantly higher dressing percentages than those at Musina (P<0.05). Impala ewes from both regions had a higher lipid content (P<0.05), but the sex of the animal had no effect on the remaining chemical parameters. The crude protein content of impala at Musina (24.88 ± 1.044%) was higher (P<0.05) than the Mara animals (23.80 ± 0.840%). Regional differences (P<0.05) were found in the amounts of phosphorous and calcium in the meat. Female animals at Mara showed higher proportions (P<0.05) of saturated (SFA), and mono-unsaturated fatty acids than the male animals. Males from both regions showed higher proportions (P<0.05) of poly-unsaturated fatty acids. Myristic, palmitic and stearic acid formed the greatest proportion of the SFA component for males and females from both regions. Samples of the M. semi-membranosus (SM), M. deltoideus (D), M. longissimus dorsi et laborum (LO), and M. psoas major (PS) were analysed for citrate synthase (CS) and phosphofructo-kinase activities. MHC distribution varied significantly between 0, SM and LD (P<O.05). D expressed more MHC I, and less MHC lIa than the other three muscle groups. Positive correlations were found between age and MHC I in 0 (r=O.93; P<O.05) and CS and weight of the animal in D (r=O.76; P<O.05). The enzyme activities and MHC distribution indicate that energy in the impala is produced to a large extent via oxidative pathways. / AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om die invloed van ouderdom, geslag, area, en uitdunmetodes op die vleiskwalitiet van rooibokke te evalueer. Veertig rooibokke is gedurende afsonderlike dag en nag uitdunningsoperasies by die Mara Landboukundige Ontwikkelings Sentrum geoes. Karkas pH45 (gemeet in die M. longissimus dorsi 45 minute post mortem) was hoër (P<0.05) in nag-geoesde diere (6.67 ± 0.11) in vergelyking met die dag-geoesde diere (6.55 ± 0.23). Die finale pH (pHu) van diere wat in die nag geoes is (5.39 ± 0.08) was laer (P<0.05) in vergelyking met die wat in die dag geoes is (5.45 ± 0.11). Nie-lineêre regressie analise toon dat die tempo van pH-daling van die nag-geoesde diere merkbaar stadiger was as die dag-geoesde diere (P<0.05). Die afkoelings tempo van die M. longissimus dorsi et lumborum was twee keer vinniger in die nag geoesde groep (P<0.05). Die gemiddelde skeurkragwaarde en drupverlies was beide laer (P<0.05) vir nag geoesde diere (respektiewelik 19.11 ± 5.67 g/mm2 en 2.93 ± 1.59%) in vergelyking met diere wat in die dag geoes is (23.42 ± 8.12 g/mm2 en 4.15 ± 2.33%). Die resultate toon dat nag-uitdunning 'n voordelige effek op vleiskwaliteit gehad het, in vergelyking met dag-uitdunning. 'n Tweede groep van rooibokke is gemonster by die Musina Eksperimentele plaas in die Limpopo Provinsie in Suid-Afrika. Die gewigte van die Mara diere (50.23 ± 9.32 kg) was hoër (P<0.05) as die van die Musina diere (44.25 ± 10.81 kg). Die Mara groep het hoër uitslag persentasies (P<0.05) gehad. Vroulike diere in beide areas het 'n hoër vet inhoud (P>O.05) gehad. Die ru-proteien inhoud van die Musina diere (24.88 ± 1.04%) was hoër (P<0.05) as die van die Mara diere (23.80 ± 0.84%). Area verskille (P<0.05) is gevind in die fosfaat en kalsium inhoud in die vleis. Vroulike diere by Mara het 'n hoër proporsie (P<0.05) van versadigde en mono-onversadige vetsure in die weefsel as manlike diere gehad. Manlike diere van beide areas het 'n hoër proporsie (P<0.05) van poli-onversadige vetsure (P<0.05) as die vroulike diere getoon. Miristien, palmitien en stearien suur was kwantitatief die belangrikste vetsure in manlike en vroulike diere van beide areas. Monsters van die M. semi-membranosus (SM), M. deltoideus (D), M. longissimus dorsi et laborum (LO), en M. psoas major (PS), van die rooibokkarkasse is ontleed vir sitraatsintase (SS) en fosfofruktokinase aktiwiteite (FFK). MSK verspreiding het merkbaar varieer tussen 0, SM en LO (P<O.05). 0 toon meer MSK I en minder MSKlia as die ander drie spiergroepe (P<O.05). Postiewe korrelasies is bevind tussen ouderdom en MSK I in 0 (r=O.93; P<O.05), asook tussen SS en die gewig van die dier in o (r=O.76; P<O.05). Die ensiemaktiwiteite en MSK verspreiding toon dat energie in die rooibok tot 'n groot mate deur die oksidatiewe paaie geproduseer word.

Thesis (M.Anim.Sc) - University of Queensland, 2005. / Includes bibliography.

Thesis (MBA)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: This study summarizes data for the consumptive wildlife industry in Namibia, both in terms of resource availability and current utilization and monetary value. Based on these data a spreadsheet-based cash-flow model is developed to simulate scenarios and to explore what constitutes the critical parameter. Based on this data synthesis and modelling, recommendations are made and conclusions drawn. Chapter one gives an overview of Namibia's economy, with special reference to the livestock and wildlife industry. The fact that the commercial livestock herd has been shrinking over the years is pointed out, as well as the stable output achieved through better management practices. The literature research has shown that wildlife ranching could be a viable alternative to livestock farming as practised in southern Africa, especially in the more arid areas with higher rainfall variability. Chapter two outlines the resource availability, based on the distribution and densities of the more common species. The occurrence of the rarer species is touched on. The point is made that it is very difficult to accurately count wildlife over large areas and that, as elsewhere, Namibia's wildlife at a regional scale is underestimated. Chapter three documents the consumptive use of wildlife. Trophy hunting, the most important segment in terms of national income, is discussed together with the live sale of game, live export of game, venison production and night culling. A comparison is made between the economic outputs of the wildlife industry versus that of the commercial cattle industry. Chapter four covers financial modelling and the economics of the wildlife industry in Namibia. A spread-sheet based deterministic model is developed to explore the cash-flow implications of various game ranching options, such as using different species mixes, owning land of different carrying capacities and offering different services. Chapter five addresses policy and legislative issues in relation to the wildlife industry. Topics such as property rights and exclusive utilization rights, industry representation and the forming of smart partnerships with primary resource users are covered. Broad recommendations are made to the Ministry of Environment and Tourism. Chapter six is used for a concluding synthesis of the previous four chapters. / AFRIKAANSE OPSOMMING: Hierdie studie som die konsumptiewe wildlewe industrie in Namibie op in terme van van beide beskikbaarheid, huidige verbruik en monetere waarde van hierdie hulpbron. Gebaseer op hierdie data is 'n kontantvloei model opgestel om vooruitskouings te simuleer, met betrekking op aanbevelings en gevolgtrekkings. Hoofstuk een gee 'n oorsig van die Namibiese ekonomie met spesiale verwysing na die vee- en wildboerdery. Daar word uitgewys dat die gesamentlike kommersiele veekudde oor die afgelope aantal jare kleiner geword het, terwyl die opbrengs stabiel gebly het deurdat better bestuurspraktyke toegepas is. Die literatuurstudie het gewys dat in suider-Afrika, wildlewe-boerdery 'n lewensvatbare alternatief kan wees vir veeboerdery, veral in die droër streke wat 'n hoër reenval speling toon. Gebaseer op die verspreiding en digtheid van die meer algemene wild, gee hoofstuk drie 'n oorsig van die beskikbaarheid van hierdie hulpbronne. Trofeejag, wat die belangrikste inkomstesektor is, word bespreek, sowel as die lewende verkoop, uitvoer en nagoes (skiet van diere gedurende die nag vir vleisproduksie) van wild, asook die wildvleis produksie. Met betrekking tot die ekonomiese uitsette, word 'n vergelyking gemaak tussen die wildlewe en kommersiele veeboerdery industrie. Hoofstuk vier dek die finansiele modelering en ekonomiese aspekte van die wildlewe industrie in Namibie. 'n Rekenaar "spreadsheet" -gebaseerde, deterministiese model is ontwikkel om die kontantvloei van verskeie opsies van wildlewe boerdery te verken. Voorbeelde sluit in die gebruik van verskillende spesie samestellings, die besit van grond met verskillende drakrag vermoëns, asook die aanbiedinge van verskeie dienste. Hoofstuk vyf bespreek die beleid en wetgewing met betrekking tot die wildlewe industrie. Onderwerpe soos eiendomsreg en eksklusiewe benuttingsregte, industrie verteenwoordiging en die stigting van "smart" vennootskappe met primere hulpbron verbruikers, word aangespreek. Aanbevelings word aan die Ministerie van Omgewing en Toerisme gemaak. Hoofstuk ses behels 'n sintese van die voorafgaande vier hoofstukke.