Genetic parameters for bodyweight, wool, and disease resistance and reproduction traits in Merino sheep. 4. Genetic relationships between and within wool traits
A. E. Huisman A B and D. J. Brown A CA Animal Genetics and Breeding Unit*, University of New England, Armidale, NSW 2351, Australia.
B Present address: Hypor, 5830 AA Boxmeer, The Netherlands.
C Corresponding author. Email: dbrown2@une.edu.au
Animal Production Science 49(4) 289-296 https://doi.org/10.1071/EA08173
Submitted: 28 May 2008 Accepted: 11 February 2009 Published: 6 April 2009
Abstract
The aim of this paper was to describe the genetic relationship among expressions at different ages of seven wool traits: greasy and clean fleece weights, fibre diameter, coefficient of variation of fibre diameter, staple length and strength, and mean fibre curvature. Genetic correlations among measurements at different ages for the same trait were moderate to high, and ranged from ~0.6 for both fleece weights to 0.9 and higher for mean fibre diameter and curvature. Generally, low to moderate genetic correlations (0.3–0.4) were estimated between fleece weights and fibre diameter, clean fleece weight and staple length, and fibre diameter and staple strength. Small positive genetic correlations (0.2) were estimated between greasy and clean fleece weight with fibre diameter coefficient of variation, and between fibre diameter and staple length. Mean fibre curvature had a negative genetic correlation (approximately –0.4) with most other wool traits, the exceptions were staple strength (~0.0) and coefficient of variation of fibre diameter (approximately –0.1). Fibre diameter, staple length and staple strength had negative genetic correlations with coefficient of variation of fibre diameter (–0.15, –0.10, and –0.61, respectively). The results indicate that for most wool traits only one measurement across ages is required to make accurate selection decisions. The relationships between traits are generally moderate to low suggesting that simultaneous genetic improvement is possible.
Additional keywords: field data, maternal correlations.
Acknowledgements
This research was funded by Meat and Livestock Australia, UNE and the NSW Department of Primary Industries. The authors would like to thank the Merino breeders and scanners who collected the pedigree and performance data used in this study. The work of Stephen Field, the Merino Genetic Services database manager, and that of Bronwyn Clarke, who manages the Merino Validation Project, is gratefully acknowledged.
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* Animal Genetics and Breeding Unit is a joint venture of the New South Wales Department of Primary Industries and the University of New England.
