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Predicted and realized responses to selection for an index of bone length and body weight in Scottish Blackface sheep 2. Correlated responses in lifetime productivity

Published online by Cambridge University Press:  02 September 2010

K. D. Atkins  and
R. Thompson
K. D. Atkins
Affiliation:
AFRC Animal Breeding Research Organisation, West Mains Road, Edinburgh EH9 3JQ
R. Thompson
Affiliation:
AFRC Animal Breeding Research Organisation, West Mains Road, Edinburgh EH9 3JQ
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Abstract

A selection experiment with Scottish Blackface sheep was used to compare predicted and realized correlated responses to selection. Three lines were maintained between 1956 and 1974 in which selection was either at random or for high and low values of an index of cannon-bone length at 8 weeks of age adjusted for body weight at the same age.

There was no evidence of asymmetrical responses in any trait. Selection for increased cannon-bone length, adjusted for body weight, resulted in (i) increased body weights at all ages between birth and maturity, (ii) increased reproduction rate, principally from increased litter size but also from small responses in ewe fertility and lamb survival and (iii) decreased survival of adult ewes. The realized genetic correlations were relatively small (up to 0·3) but mostly significantly different from zero, whereas base population genetic correlation estimates were very imprecise. The realized responses in reproduction rate were probably a consequence of the genetic response in body weight.

Type
Research Article
Information
Animal Production , Volume 43 , Issue 3 , December 1986 , pp. 437 - 445
Copyright
Copyright © British Society of Animal Science 1986

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References

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