Effect of early life selection using indirect characters on the subsequent incidence of fleece rot in a flock of south-Australian merino ewes

James, P.J., Warren, G.H., Ponzoni, R.W. and Maclachlan, H.G. (1989) Effect of early life selection using indirect characters on the subsequent incidence of fleece rot in a flock of south-Australian merino ewes. Australian Journal of Experimental Agriculture, 29 1: 9-15.


Author James, P.J.
Warren, G.H.
Ponzoni, R.W.
Maclachlan, H.G.
Title Effect of early life selection using indirect characters on the subsequent incidence of fleece rot in a flock of south-Australian merino ewes
Journal name Australian Journal of Experimental Agriculture
Publication date 1989
Sub-type Article
DOI 10.1071/EA9890009
Volume number 29
Issue number 1
ISSN 0816-1089;1446-5574
Start page 9
End page 15
Total pages 7
Place of publication Collingwood, VIC, Australia
Publisher C S I R O Publishing
Language eng
Abstract Correlations were estimated between 24 fleece and body characters measured at 1, 2, 3 and 4 years of age, and fleece rot induced by artificial wetting at 4 years of age in South Australian Merino ewes. The character most strongly and consistently related to fleece rot was greasy wool colour score which was correlated with fleece rot score when measured at all 4 ages (r = 0.21, 0.22, 0.31 and 0.26 respectively) and with liability to fleece rot when measured in 3 and 4-year-olds (r = 0.25, 0.38). A number of discriminant functions were developed from characters measured at each age and used to predict fleece rot susceptibility at 4 years of age. Culling 45% of hoggets on the basis of a function comprised of all characters measured would have reduced fleece rot by 39.3%. Culling on the basis of functions comprised of more manageable groups of characters (i.e. selected as (i) contributing significantly to the function when all characters were included, or (ii) on the basis of previous recommendations) would have reduced fleece rot by between 7.4 and 15.7% when 45% of hoggets were culled. Lower culling rates gave less reduction in fleece rot, except where the reduction was very small regardless of the per cent culled. It is concluded that in most practical situations there will be limited benefit from selecting ewes on the basis of indirect characters to reduce fleece rot susceptibility in the current generation.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article
Collection: Queensland Alliance for Agriculture and Food Innovation
 
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