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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 21 for “"Genetic progress"”.
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Effects of inbreeding and estimation of genetic progress upon preweaning traits in beef cattle
… weaning and type score at weaning, and estimate genetic progress from selection in each line of each breed. Inbreeding effects were linear and quadratic regressions of the traits mentioned on inbreeding of the calf and of the dam, each sex separately, after adjustment for years (using repeat …
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Effects of selection on highly heritable traits of purebred and hybrid beef cattle
… quality traits. These differences are important genetic resources for improving production efficiency and meat quality. Because of strong genetic antagonisms (-.56) between marbling and retail product percentage, there is limited opportunity to select within breeds to achieve high levels of both …
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Yield Improvement in Eastern Soft Red Winter Wheat from 1919 to 2009
… resistance is necessary to assess breeding progress over time, and the elucidation of underlying traits responsible for yield gains can help direct future breeding. Objectives of this study were: 1) to determine the rate and magnitude of yield progress in eastern soft red winter (SRW) wheat …
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Mælidagalíkan fyrir íslenska kúastofninn
… utilize random regression (RR) models for genetic evaluation of dairy cows but in Iceland a lactation model is still used. The objective of this study was to investigate the genetics of lactation curves of Icelandic dairy cows and the possible benefits of implementing an RR model for …
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Testing purebred and commercial combined selection in Angus: Tri-County Steer Carcass Futurity
The objective of this study was to characterize genetic relationships between growth and carcass traits measured in commercial feedlot and purebred cattle that would aid in determining the effectiveness of combined crossbred and purebred selection (CCPS) strategies for sire selection. Data included …
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Heritability and repeatability of speed for two- and three-year- old standardbred racehorses
… if there was no preadjustrnent for pace. Since genetic progress is based on selection of genetically superior sires and dams, time adjusted for pace should be used for estimation of breeding values and for objective evaluation of an individual horse's real ability to compete against horses …
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Genotype by environment interaction for feed efficiency in growing-finishing pigs in Brazil versus the Netherlands
… the possible causes of a lower than 1 genetic correlation for feed efficiency between the PB performance in the nucleus level and the CB performance mn the commercial level (rpc), and compare the properties of different traits to represent feed efficiency and the implications of their …
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Genetic parameters and genomic analysis of semen quality and fertility traits in pigs
… pig industry by assisting and disseminating the genetic progress. Currently, young boars are selected for AI based on their breeding values for production traits and selecting boars for semen traits, such as volume, concentration, motility and morphology, and for low variation in semen quality …
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Selection indices for combining marker genetic data and animal model information
… in order to obtain more accurate or earlier genetic evaluations. An improvement in accuracy or time of evaluation due to utilization of marker assisted selection (MAS) increases genetic progress. Fernando and Grossman (1989) suggested including marker information directly into the Animal …
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A diversified exploration of beef cattle genetics: miRNA and beef bull fertility in beef and dairy female populations
… expression as it relates to quantitative traits, genetic analysis of sire conception rate (SCR) in dairy cow and beef heifer populations, and the genetic correlation between SCR in both populations. The objectives of the miRNA project were to elucidate differentially expressed (DE) miRNA resulting …
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Estimation of Variance Components in Finite Polygenic Models and Complex Pedigrees
Various models of the genetic architecture of quantitative traits have been considered to provide the basis for increased genetic progress. The finite polygenic model (FPM), which contains a finite number of unlinked polygenic loci, is proposed as an improvement to the infinitesimal model (IM) for …
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Toward genetic marker-assisted improvement of aquaculture stocks
… detection and marker-assisted selection (MAS) to genetic improvement of aquaculture species. Genes affecting aquaculture performance, or quantitative trait loci (QTLs}, can be mapped in relation to naturally-occuring genetic markers. Knowledge of linkages between marker and QTL alleles can be used …
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INVESTIGATION OF RESILIENCE AND ITS GENETICSTHROUGH THE USE OF LONGITUDINAL DATA
… that resilience indicators possess some genetic merit to some extent, their true significance and methodological foundations require further investigation to enhance the understanding of these phenotypes and their application in breeding programs. Lactation curve models aiming to …
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The use of carcass traits as indicators of heifer pregnancy in Angus cattle
… pregnancy is influenced by both management and genetics, and research regarding both factors has been performed. Management practices have focused on developing heifers to an ideal body weight at breeding and using body condition scoring (BCS) to evaluate fat coverage. While BCS may provide a …
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Estimates of genetic and phenotypic parameters in Columbia and Columbia X Southdale sheep
… and yearling ages as well as the phenotypic and genetic correlations among these traits. Information was acquired concerning the effects of year of birth, age of dam, type of birth and rearing, sex, breed, and station on the weanling and yearling traits considered. Data were available on 2442 …
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Determining the digestible lysine requirement of 22 to 47 week-old Lohmann laying hens using two requirement titration methodologies
Over the past 15 to 40 years, genetic improvements have been made to obtain higher egg production for commercial laying hens. In addition to genetic progress, there have been substantial changes in environmental management, cage density and feed ingredient quality. These changes have resulted in …
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Investigations of achromobacter xylosoxidans and ralstonia pickettii in porcine semen extension systems
… industry to improve reproductive efficiency and genetic progress through artificial insemination. Through the dilution and extension of the life of the sperm cell, other organisms such as bacteria are also maintained and can produce a negative impact on sperm cell motility and potential …
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The effect of interval between inseminations and semen handling on in-vivo and in-vitro fertility of frozen-thawed boar sperm
… played a substantial part in the advancement of genetic progress in the production livestock industries. However, the swine industry has not yet been able to capitalize on the potential of frozen-thawed boar sperm (FTS), due to the biological sensitivity of the sperm cells and the lower resulting …
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Integrated genetic evaluation of breeding field test traits, competition traits and test status in Icelandic horses
… to bias in estimated breeding values and retards genetic improvement. The main aim of this thesis was to study integrated genetic evaluation of competition traits and breeding field test traits for Icelandic horses where the effects of preselection in the data were accounted for. Genetic …
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Evaluation of soybean aphid resistance, yield qtl confirmation, and genetic gain in soybean
… objective of increasing the understanding of the genetics of soybean aphid resistance. In addition, 104 soybean aphid resistant PIs were haplotyped in the regions of Rag1 and Rag2 to gain information about the commonalities and differences in the genetic regions surrounding these genes. Resistance …
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