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Genome-Wide Selection for Improvement of Indigenous Pigs in Tropical Developing Countries

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dc.contributor.advisor Robinson, J. Andrew B.
dc.contributor.author Akanno, Everestus Chima
dc.date.accessioned 2012-01-11T20:08:28Z
dc.date.available 2012-01-11T20:08:28Z
dc.date.copyright 2012-01
dc.date.created 2012-01-06
dc.date.issued 2012-01-11
dc.identifier.uri http://hdl.handle.net/10214/3264
dc.description.abstract Genetic improvement of indigenous pig populations in tropical developing countries can make a significant contribution to the conservation and utilization of local genetic resources. Designing a swine breeding program requires knowledge of genetic parameters for economically important traits. A meta-analysis of genetic parameters determined under tropical conditions and published from 1974 to 2009 was carried out to provide consensus estimates of genetic parameters. Given that the data recording and analysis infrastructure for implementing the conventional best linear unbiased prediction (BLUP) methods is generally lacking in developing countries, Genome-wide selection (GS) provides an approach for achieving faster genetic progress without developing a pedigree recording system. A simulation study was carried out to evaluate the option of using available 60 K single nucleotide polymorphism marker panel. The observed levels of linkage disequilibrium (LD) in the tropical pig populations were simulated and utilized. Genomic predictions were from ridge regression analysis. The results showed that expected accuracies of genomic breeding values (GBV) were in the range of 0.31 - 0.86 for the validation set. Genome-wide selection improved accuracy of GBVs over conventional BLUP method for traits with low heritability and in young animals with no performance data. Crossbred training populations had higher accuracy than purebred training populations. An assessment of the opportunities for GS in tropical pig breeding was conducted. Genome-wide selection performed better than conventional methods by increasing genetic gain and maintaining genetic variation while lowering inbreeding especially for traits with low heritability, by exploiting LD and the Mendelian sampling effects. Combining GS with repeated backcrossing of crossbreds to the selected exotic population in moderate LD promises faster improvements of the commercial population. A two-step selection strategy that involves the use of GS to pre-select candidates that entered the performance test station and for selecting replacement candidates in a nucleus swine breeding program was evaluated and compared to other conventional approaches. Genome-wide selection generated an increase of about 38% to 172% in annual returns compared to other conventional approaches for previously selected population in moderate LD and about 2% to 50% increases in return for unselected population in low LD. en_US
dc.description.sponsorship Canadian Commonwealth Scholarship and Fellowship Program, University of Guelph en_US
dc.language.iso en en_US
dc.subject Genome-wide selection en_US
dc.subject Swine en_US
dc.subject Tropical developing countries en_US
dc.subject Simulation en_US
dc.subject Genetic parameters en_US
dc.subject Meta-analysis en_US
dc.title Genome-Wide Selection for Improvement of Indigenous Pigs in Tropical Developing Countries en_US
dc.type Thesis en_US
dc.degree.programme Animal and Poultry Science en_US
dc.degree.name Doctor of Philosophy en_US
dc.degree.department Department of Animal and Poultry Science en_US
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