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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

Assessing productivity and diversity of South African chicken genetic resources

Mtileni, B. J. 12 1900 (has links)
Thesis (PhD (Animal Sciences))--Stellenbosch University, 2011. / ENGLISH ABSTRACT: The current study was undertaken to determine the effectiveness of the current South African chicken conservation programmes in conserving the genetic diversity of village chicken populations. Village chicken farmer’s production constraints such as feed availability, chicken mortality, prevalence of diseases and chicken sales were influenced by gender, age, wealth status, production system, chicken flock size, type of chicken breed owned, accessibility of veterinary services, availability of supplements, vaccines and shelter. Considerable phenotypic heterogeneity in qualitative traits of indigenous chicken populations and their distributions in different regions of South Africa revealed the absence of selection on a preferred phenotype, showing that the population is not standardized. Genetic diversity studies using both microsatellites and mtDNA markers demonstrated that the conservation flocks of South African chickens displayed considerable genetic variability that is different from that of the assumed founder populations (field chicken populations). The indigenous chicken mtDNA further revealed multiple maternal lineages in South African chickens, where conservation flocks and field chicken populations shared these major haplotypes A, D and E which are presumed to be of Chinese, South East Asia and Indian subcontinent origin, respectively. The overall findings of the study increased awareness of the importance of genetic management and utilization of indigenous chicken genetic resources of South Africa. As a result, the study provides a base-line dataset to complement the decision-making process on designing proper conservation strategies for South African indigenous chicken genetic resources. / AFRIKAANSE OPSOMMING: Die huidige studie is onderneem om die doeltreffendheid van die Suid-Afrikaanse hoenderbewarings programme in die bewaring van genetiese diversiteit in dorphoender bevolkings. Dorp hoenderboere se produksie beperkinge soos voerbeskikbaarheid, hoender mortaliteit, die voorkoms van siektes en hoenderverkope word beïnvloed deur geslag, ouderdom, rykdom status, produksie sisteem, hoender kudde grootte, tipe hoenderras, toegang tot veeartsenydienste, beskikbaarheid van supplemente, inentstowwe en skuiling. Merkbare fenotipiese variasie in kwalitatiewe eienskappe van die inheemse hoenderbevolking en hul verspreiding in verskillende areas van Suid-Afrika, is aanduidend dat daar nie seleksie plaasvind vir ‘n voorkeur fenotipe nie, wat dus toon dat die bevolking nie gestandardiseer is nie. Genetiese diversiteit studies met behulp van beide mikrosatelliete en mtDNA merkers het getoon dat die bewaringskuddes van Suid- Afrikaanse hoenders vertoon merkbare genetiese variasie wat verskil van die veronderstelde stigter bevolkings (veldhoender populasies). Die inheemse hoenders mtDNA het verder onthul dat verskeie moederlike afstammelinge in die Suid Afrikaanse hoenders, major haplotipes A, D, E wat afkomstig is vanaf die Chinese, Suid-Oos Asië en die Indiese subkontitent onderskeidelik; gedeel word saam met die bewaringskuddes en die veldhoender populasie. Die algemene bevindige van die studie verhoog die bewustheid van die belangrikheid van genetiese bestuur en benutting van inheemse hoender genetiese hulpbronne van Suid-Afrika. As gevolg hiervan, verskaf die studie ‘n basis-lyn datastel vir die besluitnemingproses oor die ontwerp van ‘n ordentlike bewaring strategieë vir die Suid-Afrikaanse inheemse hoender genetiese hulpbronne.

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