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RESEARCH ARTICLE
Contents Vol 49(12)

Effects of weaner nutrition on sire and flock rankings: a re-analysis of historical data

B. J. McGuirk
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Strowan Lodge, 1c Albert Terrace, Edinburgh EH10 5EA, UK. Email: brianmcguirk@bigpond.com

Animal Production Science 49(12) 1100-1104 https://doi.org/10.1071/AN09032
Submitted: 27 February 2009  Accepted: 29 July 2009   Published: 16 November 2009

Abstract

Early work in the 1950s on the wool growth response of sheep from diverse genotypes for wool production in response to varying planes of nutrition at pasture did not show the significant genotype × environment interactions exhibited in later pen studies with the same or very similar genotypes. However, this early study used a log-transformation on all traits to adjust nutritional effects for scale. Re-analysis of the original (i.e. untransformed) data shows that superior genetic merit for clean fleece weight, different sire progeny groups or selection flocks is more apparent when hogget ewes are fed a high plane of nutrition at pasture. However, only in the case of flocks was the interaction statistically significant, and this interaction was insignificant when data were either log-transformed, or when an appropriate test that accounts for scale-type effects was applied. When left untransformed, the data are, thus, in agreement with the subsequent pen studies that examined data on untransformed clean wool production.


Acknowledgements

I am grateful to Professor John James, for his advice throughout this study, to the Director of Research, Trangie Agricultural Research Centre, for access to the data and for permission to publish these results, to Dr Arthur Gilmour, for the ASReml analyses, and to Dr Kevin Atkins for his assistance and helpful comments.


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