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A genetic analysis of early growth and ultrasonic measurements in hill sheep

Published online by Cambridge University Press:  02 September 2010

J. Conington ,
S. C. Bishop ,
A. Waterhouse  and
G. Simm
J. Conington
Affiliation:
Scottish Agricultural College, West Mains Road, Edinburgh EH9 3JG
S. C. Bishop
Affiliation:
Roslin Institute(Edinburgh), Roslin, Midlothian EH25 9PS
A. Waterhouse
Affiliation:
Scottish Agricultural College, Auchincruive, Ayr KA6 5HW
G. Simm
Affiliation:
Scottish Agricultural College, West Mains Road, Edinburgh EH9 3JG
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Abstract

Genetic parameters were estimated for early lamb growth and ultrasonic measurements taken on Scottish Blackface lambs reared under extensive conditions on two Scottish hill farms. Measurements were taken on approximately 2000 lambs born to unselected ewes, and sired by 32 rams previously selected for divergent predicted carcass lean content. Heritabilities for birth weight, marking iveight (at approx. 6 weeks of age) and weaning weight (at 17 weeks) were 0·07 (s.e. 0·04), 0·02 (s.e. 0·03), and 0·14 (s.e. 0·05), respectively. Heritabilities for ultrasonic muscle and fat depths at weaning were 0·27 (s.e. 0·09) and 0·16 (s.e. 0·06), respectively. There was a strong maternal effect on weight which declined from birth with lamb age and was relatively unimportant for the ultrasonic measurements. The rearing environment of the lambs (hill pasture v. ‘improved’ (or ‘inbye’) pasture) was an important environmental effect on the heritability estimate for backfat thickness, with that for lambs reared on improved pasture being twice that of hill-reared lambs. The implications of the results from this work on genetic improvement of sheep in liill environments are discussed.

Keywords

environmental factorsgenetic parameterssheepultrasonic measurements
Type
Research Article
Information
Animal Science , Volume 61 , Issue 1 , August 1995 , pp. 85 - 93
Copyright
Copyright © British Society of Animal Science 1995

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