Predicted responses in Merino sheep from selection combining visually assessed and measured traits
S. I. Mortimer A C , K. D. Atkins B , S. J. Semple B and N. M. Fogarty BA Industry & Investment NSW, Agricultural Research Centre, Trangie, NSW 2823, Australia.
B Industry & Investment NSW, Orange Agricultural Institute, Orange, NSW 2800, Australia.
C Corresponding author. Email: sue.mortimer@industry.nsw.gov.au
Animal Production Science 50(10) 976-982 https://doi.org/10.1071/AN10085
Submitted: 26 May 2010 Accepted: 30 July 2010 Published: 21 October 2010
Abstract
Visually assessed traits for wool quality and ease of management are important to Merino sheep breeders and need to be considered in breeding programs. The present study reports on the predicted correlated responses in visual traits from selection using a range of standard MERINOSELECT™ indices available for use in Australian Merino breeding programs. The effect of including a visual trait in the index is also reported. The visual scored traits were classer grade, wool quality (handle, character and colour), conformation (neck and body wrinkle, front and back leg structure) and fleece rot. The indices covered a range of micron premiums of varying emphasis on increasing fleece weight and reducing fibre diameter. The indices were for Merino wool enterprises (Merino 14%, Merino 7% and Merino 3.5%) and Merino dual purpose wool and meat enterprises (Dual Purpose 7% and Dual Purpose 3.5%). The breeding objectives for the indices included fleece weight, fibre diameter, coefficient of variation of fibre diameter, staple strength, bodyweight and reproduction. Selection over 10 years using the standard MERINOSELECT™ indices is predicted to result in a small correlated improvement in the wool quality traits and classer grade, with a slight deterioration in fleece rot score. The improvement in wool handle, character and colour are greater with those indices that have a greater emphasis on reducing fibre diameter than with those increasing fleece weight. Indices with more emphasis on increased fleece weight than on reduced fibre diameter are predicted to result in small increases in neck and body wrinkle scores and a slight deterioration in wool colour. Inclusion of classer grade, handle, character or colour provided slight extra gains in fleece weight for indices that emphasised reduced fibre diameter through increased accuracy of selection.
Additional keywords: classer grade, crimp, handle, subjective traits, wool quality.
Acknowledgements
Financial support for this study was provided by Australian wool growers and the Australian Government through Australian Wool Innovation Limited.
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