Genetic parameter analysis of bareness and tail traits in New Zealand sheep.pdf (323.75 kB)

Genetic parameter analysis of bareness and tail traits in New Zealand sheep

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posted on 2023-06-22, 21:25 authored by Tricia JohnsonTricia Johnson, David Scobie, Ken DoddsKen Dodds, Sarah-Jane Powdrell, Suzanne RoweSuzanne Rowe, Kathryn McRaeKathryn McRae

Physical traits that improve welfare and disease outcomes for sheep are becoming increasingly important due to both increased climate challenges and societal expectations. Such traits include tail length, the amount of skin (vs. wool) on the underside of the tail, and the area of no-wool (hair) on the belly and breech areas (surrounding the anus) of the animal. An industry dataset consisting of records from individual stud breeders and industry progeny tests was available to estimate the genetic parameters associated with these traits and to investigate the potential for within-breed genetic selection. The heritability estimate for tail length was 0.68 ± 0.01 when breed was not fitted, and 0.63 ± 0.01 when breed was fitted. Similar trends were observed for breech and belly bareness which had heritability estimates around 0.50 (± 0.01). The estimates for these bareness traits are both higher than previous reports from animals of the same age. There was, however, between breed variation in the starting point for these traits, with some breeds having significantly longer tails and a wooly breech and belly, and limited variability. Overall, the results of this study show that flocks exhibiting some variation will be able to make rapid genetic progress in selecting for bareness and tail length traits, and therefore have the potential to make progress towards a sheep that is easier to look after and suffers fewer welfare insults. For those breeds that showed limited within-breed variation, outcrossing may be required to introduce genotypes that exhibit shorter tail length and bareness of belly and breech to increase the rate of genetic gain. Whatever approach is taken by the industry, these results support that genetic improvement can be used to breed “ethically improved sheep”.


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© The Author(s) 2023. Published by Oxford University Press on behalf of the American Society of Animal Science. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial License (, which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Oxford University Press

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Journal of Animal Science



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