Genetic and phenotypic parameter estimates of production traits of Merino sheep in an arid environment

Abstract

Genetic and phenotypic parameters were estimated in the control line of the Klerefontein Merino sheep selection experiment. The heritability estimates of 0,247 for body mass, 0,229 for clean fleece mass and 0,369 for fibre diameter are generally lower than other published estimates. Henderson's Method 3 and REML on a sire model produced almost identical estimates. Phenotypic, environmental and genetic correlation between the three traits were all positive low. As with many other published results, genetic correlations were characterized by large standard errors of estimation. The limitations of traditional estimators is briefly discussed.

Genetiese en fenotipiese parameters is in die kontrolelyn van die Klerefontein Merinoseleksie-eksperiment beraam. Die oorerflikheidsberamings van 0,247 vir liggaamsmassa, 0,229 vir skoonvagmassa en 0,369 vir veseldikte is oor die algemeen laer as ander gepubliseerde beramings. Henderson se Metode 3 en REML op 'n vaarmodel het bykans identiese beramings gelewer. Fenotipiese, omgewings- en genetiese korrelasies tussen die drie kenmerke was almal positief laag. Soos met baie ander gepubliseerde resultate, is genetiese korrelasies deur hoë standaardfoute gekenmerk. Die leemtes van tradisionele beramers word kortliks bespreek.

Keywords: Arid regions, genetic parameters, Merino, phenotypic parameters.