Genetic parameters for subjectively assessed wool and conformation traits in the Tygerhoek Merino flock

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dc.contributor.authorMatebesi, P. A.en_ZA
dc.contributor.authorVan Wyk, J. B.en_ZA
dc.contributor.authorCloete, S. W. P. (Schalk Willem Petrus van der Merwe)en_ZA
dc.date.accessioned2011-05-15T15:54:38Z
dc.date.available2011-05-15T15:54:38Z
dc.date.issued2009
dc.descriptionCITATION: Matebesi, P. A., Van Wyk, J. B. & Cloete, S. W. P. 2009. Genetic parameters for subjectively assessed wool and conformation traits in the Tygerhoek Merino flock. South African Journal of Animal Science, 39(3):176-187.
dc.descriptionThe original publication is available at https://www.sasas.co.za
dc.description.abstractRecords of the Tygerhoek Merino resource flock were used to estimate genetic, phenotypic and environmental parameters for subjectively assessed wool and conformation traits. The database consisted of records of 4 495 animals, the progeny of 449 sires and 1 831 dams born in the period 1989 to 2004. The pedigree records have been collected between 1969 and 2004. Direct heritability estimates (h2a) for subjective wool traits ranged from 0.15 for face cover score to 0.50 for woolly face score. Corresponding h2a for subjective conformation traits ranged from 0.13 for topline (TOPL) to 0.39 for total fold score (TOT). Maternal heritability estimates were all below 10% where applicable. The proportion of the total phenotypic variance due to the maternal permanent environment variance (c2pe) amounted to 5% for general head conformation (GEN). The genetic correlation between animal effects ranged from -0.70 to 0.21 where applicable. Among the subjective wool traits favourable genetic correlations (rg) were estimated between regularity of crimp (ROC) and wool colour (COL) (0.31), for wool quality (QUAL) with ROC (0.49) and COL (0.26) and between staple formation (STAPL) and belly and points (BANDP) (0.58). The relationships between ROC and STAPL (-0.49) and for QUAL with STAPL (-0.45) and BANDP (-0.20) were unfavourable. The noteworthy relationships among subjective conformation traits were those between the conformation of the hind legs and the conformation of the front legs (0.71) and of GEN and TOPL with TOT (-0.31 and -0.47 respectively). The rg of significance between subjective wool and conformation traits were variable in sign and magnitude. These results indicated the possibility to achieve sustained genetic improvement by selection for subjective wool and conformation traits in South African Merino sheep.
dc.description.urihttps://www.sasas.co.za/journals/genetic-parameters-for-subjectively-assessed-wool-and-conformation-traits-in-the-tygerhoek-merino-flock/
dc.description.versionPublisher's version
dc.format.extent12 pages
dc.identifier.citationMatebesi, P. A., Van Wyk, J. B. & Cloete, S. W. P. 2009. Genetic parameters for subjectively assessed wool and conformation traits in the Tygerhoek Merino flock. South African Journal of Animal Science, 39(3):176-187
dc.identifier.issn2221-4062 (online)
dc.identifier.urihttp://hdl.handle.net/10019.1/9317
dc.language.isoen_ZAen_ZA
dc.publisherSouth African Journal of Animal Sciences
dc.rights.holderAuthors retain copyright
dc.subjectWool
dc.subjectMerino sheep -- Breeding
dc.subjectMerino sheep
dc.titleGenetic parameters for subjectively assessed wool and conformation traits in the Tygerhoek Merino flocken_ZA
dc.typeArticle
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