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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Production systems, phenotypic and genetic differentiation of pig genetic resources in Zimbabwe, Malawi and South Africa

Halimani, T. E. 12 1900 (has links)
Thesis (PhD (Animal Sciences))--Stellenbosch University, 2011. / ENGLISH ABSTRACT: Local pigs in Southern Africa are an important component of resource-based subsistence farming systems and contribute substantially to the improvement of livelihoods of farmers. The objective of the study was to characterise indigenous pigs through the following specific objectives: to characterise the production systems, to give a physical description and to evaluate the genetic differentiation of the indigenous pigs. Surveys were carried out in Chirumhanzu and Mutoko Districts of Zimbabwe, Afred Nzo, OR Tambo and Vhembe districts of South Africa. Blood samples were collected in all of the above and additional three districts in Malawi (Mchinji, Dedza and Salima). The first study showed that most of the indigenous pigs were kept by women. The farmers kept small herd sizes (<7 pigs) to match the available resources. Income was the main determinant of farmer production objectives and breed preference. Several constraints that would militate against in situ conservation included poor quality and quantity of feeds, diseases, lack of housing, lack of markets and lack of support services. The pigs were generally small and black resembling the Windsnyer-Mukota type of pigs. The pigs apparently had a high foraging ability and high thermo-tolerance that made them suitable for production in low-intensity management free range production systems. These types of pigs were distributed throughout the study area. A microsatellite analysis showed high diversity but very little population differentiation among the pig populations from Southern Africa, with 93 % of variety occurring within subpopulations. Development of markets can be a feasible way of mainstreaming the indigenous pigs into the general economy. This will achieve the twin objectives of conserving and improving the breed while, at the same time, benefitting the farmers that keep these genetic resources. Farmers faced similar production constraints and the pigs were similar across the study areas. / AFRIKAANSE OPSOMMING: Plaaslike varke speel ‘n belangrike rol in hulpbron-gebaseerde bestaansboederye in Suider- Afrika, en maak ‘n aansienlike bydrae tot verbetering van die lewensbestaan van bestaansboere. Die studie het die volgende doelwitte: om die produksie van inheemse varke te karakteriseer, die varke fisies te beskryf, en om die genetiese differensiasie van die inheemse varke te evalueer. Opnames is uitgevoer in die Chirumhanzu en Mutoko distrikte van Zimbabwe, Afred Nzo, OR Tambo en Vhembe distrikte in Suid-Afrika. Bloedmonsters is in al die bogenoemde en nog drie distrikte in Malawi (Mchinji, Dedza en Salima) versamel. Die eerste studie het getoon dat die meeste inheemse varke deur vroue aangehou word. Die boere het klein trop groottes vir aanpasbaarheid by die beskikbare hulpbronne. Inkomste en varkras voorkeur was die hoof bepalende faktore vir hierdie boere se produksie doelwitte. Verskeie beperkings wat bots teen in situ instandhouding sluit in swak kwaliteit- en kwantiteit voere, siektes, gebrek aan behuising, die gebrek aan markte en die gebrek aan ondersteunende dienste. Die varke is oor die algemeen klein en swart en vertoon soos die Windsnyer-Mukoto tipe varke. Hierdie varke het blykbaar ‘n hoë voer-soekende vermoë en hitte-verdraagsaamheid wat hulle geskik maak vir die produksie in lae-intensiteit bestuur en vry-weidende produksie sisteme. Hierdie tipe varke was versprei oor die studie area. ‘n Mikrosatelliet analise het aangedui dat daar hoë genetiese variasie is binne die vark populasie, maar daar is klein differensiasie tussen die verskillende vark populasies van Suider-Afrika, met 93% variasie wat voorkom binne sub-populasies. Die ontwikkeling van markte kan ‘n haalbare manier wees om die inheemse varke toegang te gee tot die algemene ekonomie. Hiermee kan beide doelwitte, bewaring en verbetering van hierdie varkras, tergelyktydig bereik word, ten goede van die boere wat hierdie genetiese hulpbronne aanhou.

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