The evaluation of a South African fine wool genetic resource flock

[摘要] ENGLISH ABSTRACT: This study set out to determine (co)variance components for the important production, reproduction andconformation traits of a South African fine wool resource flock that was established at the request of theSouth African wool industry. A secondary aim was to assess progeny of these animals under pastoralconditions in areas where the production of fine wool is uncommon. The Cradock fine wool Merino studwas established in 1988 with ewes bought from producers with the finest clips in South Africa. Datacollected from 1988 to 2010 were used to estimate the (co)variances for the genetic fine wool resourceflock. The quantification of the interdependencies of fibre diameter (FD) with production, reproduction andsubjective traits were the main objective of this study. It is evident from the results of this study that FD isa highly heritable (0.63 ± 0.03) trait, which can lead to marked genetic progress provided that there areadequate levels of phenotypic variation available during selection. Fibre diameter was unfavourablycorrelated with body weight (0.30 ± 0.05), clean fleece weight (0.24 ± 0.05) and reproduction (0.59 ±0.18), which implies that selection for reduced FD can have a detrimental effect on all these traits.Despite these unfavourable genetic correlations genetic gain in the other economical important traits wasachievable in the stud (-0.129 ± 0.033). These results were supported by the results obtained during theevaluation of progeny of this stud under pastoral conditions where the production and reproduction of thefine wool animals were comparable with medium wool animals. It can therefore be concluded thatselection for reduced FD can be practiced without detrimental effects on the economically important traitsand subsequently the profitability of the sheep enterprise, as long as breeders have a reasonableselection objective based on economic considerations.

[发布机构] Stellenbosch University