Quantitative genetic analyses of production and reproduction traits in Australian merino sheep
Access status:
Open Access
Type
ThesisThesis type
Doctor of PhilosophyAuthor/s
Vaez Torshizi, RasoulAbstract
Restricted Maximum Likelihood (REML) procedures based on a derivative-free algorithm using the Simplex method and fitting an animal model were used to estimate variance and covariance components for several performances of productive traits, namely, body weight measured at birth, ...
See moreRestricted Maximum Likelihood (REML) procedures based on a derivative-free algorithm using the Simplex method and fitting an animal model were used to estimate variance and covariance components for several performances of productive traits, namely, body weight measured at birth, weaning, 10 month, 16 month and 22 months of age, greasy fleece average daily gain to 4, 10, 16 and 22 months of age, clean fleece average daily gain to 10, 16, 22 months of age and mean fibre diameter measured at 10, 16 and 22 months of age. For these traits, the importance of maternal effects, either additive genetic or environmental, were investigated. The interrelationship among the performances of each trait were studied, and then were used to determine the efficiencies of indirect selection at early ages compared with later ages for improvement of an animal's lifetime production.
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See moreRestricted Maximum Likelihood (REML) procedures based on a derivative-free algorithm using the Simplex method and fitting an animal model were used to estimate variance and covariance components for several performances of productive traits, namely, body weight measured at birth, weaning, 10 month, 16 month and 22 months of age, greasy fleece average daily gain to 4, 10, 16 and 22 months of age, clean fleece average daily gain to 10, 16, 22 months of age and mean fibre diameter measured at 10, 16 and 22 months of age. For these traits, the importance of maternal effects, either additive genetic or environmental, were investigated. The interrelationship among the performances of each trait were studied, and then were used to determine the efficiencies of indirect selection at early ages compared with later ages for improvement of an animal's lifetime production.
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Date
1996Rights statement
The author retains copyright of this thesis. It may only be used for the purposes of research and study. It must not be used for any other purposes and may not be transmitted or shared with others without prior permission.Awarding institution
The University of SydneyShare