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dc.contributor.advisorFair, M. D.
dc.contributor.advisorNeser, F. W. C.
dc.contributor.authorKing, Felix Joao Manuel
dc.date.accessioned2015-09-04T07:41:39Z
dc.date.available2015-09-04T07:41:39Z
dc.date.copyright2009-12
dc.date.issued2009-12
dc.date.submitted2009-12
dc.identifier.urihttp://hdl.handle.net/11660/1158
dc.description.abstractEnglish: In the first study performance data from 465 Boer goat rams tested in a central performance test in the Northern Cape Veld-Ram Club from 1989 to 2007 were analysed to determine the relationship between performance and sale price. Rams were subjected to extensive management conditions on natural pastures for 160 days and finished-off in a feedlot for 50 days. Upon the conclusion of the entire test period, the rams were auctioned. Performance information was available for buyers for decision making. Traits analysed included final weight (FW), final weight index (FWI), average daily gain (ADG), average daily gain index (ADGI), growth per day of age index (ADOI), Kleiber ratio (KR), auction weight (AW), scrotal circumference (SC), selection index (SI) and sale price (SP). Stepwise regression analyses, using proc GLM of SAS were performed to identify variables that significantly influenced sale prices. Final weight was significant in eight out of eighteen years, auction weight was significant in six of the seven years measured and selection index influenced prices in seven out of ten years. Scrotal circumference, average daily gain, final weight index, average daily gain index and Kleiber ratio had little influence on sale price. Growth per day of age index did not show any influence on sale price. Price was positively correlated (P<0.05) with many of the performance traits. All significant correlations were moderate to high and ranged from 0.37 to 0.80. The amount of variation in sale price accounted for by the performance traits ranged from 15% in year 1991 to 65% in 1998. The most important traits influencing sale price (SP) were final weight, auction weight, and selection index. The results indicated that buyers of stud rams put more emphasis on production traits such as body weight and that they recognize the importance of performance data as shown by their preference for animals with high selection indices. In the second study data consisting of 3855 records and collected from 1998 to 2008 were analysed to estimate genetic parameters for economic traits in two Boer goat flocks. The traits investigated were weaning weight and post-weaning weight. Least square analysis was used for estimation of environmental effects. Genetic parameters were estimated from single and bivariate trait analyses using ASREML software fitting animal models. By ignoring or including maternal additive genetic effects and their covariance and maternal permanent environmental effects seven different models were fitted for each trait. The fixed effects of sex, type of birth, age of dam, year of birth, herd, season and age of lamb, were all significant (P<0.05) for both traits. The direct heritability estimates varied from 0.24 for weaning weight to 0.31 for post-weaning weight. The corresponding maternal permanent environment due to the dam was 0.10 and 0.44 respectively. The maternal heritability (0.03) for weaning weight was lower than its corresponding direct heritability. Estimates of genetic parameters in this study confirmed that selection for weaning weight would result in genetic improvement of Boer goats.en_ZA
dc.description.abstractAfrikaans: In die eerste studie word data van prestasie eienskappe van 465 ramme getoets in ‘n sentrale prestasie toets by ‘n Noord-Kaap Veld-Ram Club vanaf 1989 tot 2007 ontleed om te bepaal wat die verhouding, indien enige, tussen die prestasie eienskappe en die verkoopprys is. Ramme is onderworpe aan ekstensiewe toestande op natuurlike weiding vir 160 dae afgerond in 'n voerkraal vir 50 dae. Na voltooiing van die afronding, was die die ramme opgeveil. Prestasie inligting was beskikbaar vir die koper vir besluitneming. Eienskappe ingesluit in die analiese was finale gewig (FW), finale gewig indeks (FWI), gemiddelde daaglikse toename (GDT), gemiddelde daaglikse toename indeks (ADGI), groei per dag van ouderdom-indeks (ADOI), Kleiber verhouding (KR), veiling gewig (AW), skrotumomtrek (SC), seleksie-indeks (SI) en verkoopprys (SP). Stapsgewyse regressie-analieses, met behulp van “proc” GLM van SAS is uitgevoer om te identifiseer watter eienskappe kooppryse betekenisvol beïnvloed. Finale gewig is betekenisvol in agt van die agtien jaar, veiling gewig was betekenisvol in ses van die sewe jaar gemeet en die seleksie-indeks beïnvloed pryse betekenisvol in sewe van die tien jaar. Skrotale omtrek, gemiddelde daaglikse toename, finale gewig indeks, gemiddelde daaglikse toename indeks en Kleiber verhouding het min invloed op die verkoop prys. Groei per dag van ouderdom-indeks toon nie enige invloed op die verkoop prys nie. Prys was positief en betekenisvol gekorreleerd (P<0,05) met baie van die prestasie eienskappe. Alle betekenisvolle korrelasies was matig tot hoog (0.37 0.80). Die parsiëele bydrae van die prestasie eienskappe tot die verkoop prys was vanaf 15% in jaar 1991 tot 65% in 1998. Die belangrikste eienskappe wat verkoop prys beïnvloed was finale gewig, veiling gewig, en die seleksie-indeks. Die resultate dui daarop dat kopers van stoet ramme meer klem lê op die produksie eienskappe soos die liggaamgewig en herken die belangrikheid van die prestasie eienskappe soos aangedui deur ’n voorkeur vir diere met 'n hoë seleksie-indeks. In die tweede studie is data versamel van 1998 tot 2008 ontleed om genetiese parameters te bereken vir twee van die ekonomiese produksie eienskappe speengewig en na-speengewig van Boerbokke. . Analises van kleinste kwadrate is vir die beraming van omgewing-effekte met SAS uitgevoer. Genetiese parameters van enkel eienskap modelle is met behulp van ASREML sagteware bereken. Sewe verskillende modelle is vir elke eienskap getoets. Die modelle het direk geneties en maternale effekte (in of uitgesluit) en permanente toevallige effekte met hul kovariansie (in of uitgesluit). Die vaste-effekte van seks, tipe van geboorte, ouderdom van ooie, jaar van geboorte, kudde, seisoen en die ouderdom van lam, was almal betekenisvol (P <0,05) vir beide speengewig en na-speengewig. Die direkte oorerflikheids beramings het gewissel van 0.24 vir speengewig tot 0.31 vir na-speengewig. Die ooreenstemmende permanente maternale omgewing as gevolg van die ooie is 0.10 en 0.44 onderskeidelik. Die maternale oorerflikheid (0.03) vir speengewig was laer as die ooreenstemmende direkte oorerflikheid. Beramings van genetiese parameters in hierdie studie bevestig dat seleksie vir speengewig, kan lei tot die genetiese verbetering van die Boerbok.af
dc.description.sponsorshipSADC Secretariaten_ZA
dc.language.isoenen_ZA
dc.publisherUniversity of the Free Stateen_ZA
dc.subjectGoat breeds -- South Africaen_ZA
dc.subjectGoats -- Breedingen_ZA
dc.subjectDissertation (M.Sc.Agric. (Animal, Wildlife and Grassland Sciences))--University of the Free State, 2009en_ZA
dc.titleProduction parameters for Boer goats in South Africaen_ZA
dc.typeDissertationen_ZA
dc.rights.holderUniversity of the Free Stateen_ZA


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