Hostname: page-component-586b7cd67f-rdxmf Total loading time: 0 Render date: 2024-11-30T19:43:13.663Z Has data issue: false hasContentIssue false
  • English
  • Français

Genetic parameters of growth between birth and sixteen weeks in Down Cross Sheep

Published online by Cambridge University Press:  02 September 2010

J. C. Bowman  and
J. S. Broadbent
J. C. Bowman
Affiliation:
Research Division, Thornber Brothers Ltd., Mytholmroyd, Yorkshire
J. S. Broadbent
Affiliation:
Research Division, Thornber Brothers Ltd., Mytholmroyd, Yorkshire
Get access

Extract

This paper reports a paternal half sib analysis of data collected over 3 years to estimate additive genetic variance of growth between birth and 16 weeks in crossbred progeny derived from Down rams. The data were divided into two groups and pooled estimates of parameters obtained by two methods. The paternal half sib intra-class correlations varied between 0·017 and 0·057 depending on pooling group and method. It is suggested that such low correlations arise because (a) most of the lambs in the study were still sucking at slaughter, close to 16 weeks of age, and the trait measured is thus largely influenced by maternal milking ability (b) the selection practised in the Down breeds may have been effective and reduced genetic variation and (c) there is considerable inbreeding in the Down breeds.

In further analysis of data from four farms involving rams mated to more than one breed of ewe there was limited evidence of specific combining ability of growth between birth and 16 weeks of age for Welsh ewes compared to ewes of other breeds.

Type
Research Article
Information
Animal Production , Volume 8 , Issue 1 , February 1966 , pp. 129 - 135
Copyright
Copyright © British Society of Animal Science 1966

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Bichard, Maurice, & Yalcin, B. C., 1964. Crossbred sheep production. III. Selection for growth rate and carcass attributes in the second-cross lamb. Anim. Prod., 6: 6–179.Google Scholar
Broadbent, J. S., 1962. An assessment of the value of performance testing as an aid to selection of crossing rams used in fat lamb production. Ph.D. Thesis. University of Wales.Google Scholar
Broadbent, J. S., & Bowman, J. C., 1964. Progeny testing of Suffolk rams on three maternal breeds. Anim. Prod., 6: 215–225.Google Scholar
Terrill, C. E., 1962. Heritability estimates: farm animals. Pt. II. Sheep. In Growth: including reproduction and morphological development. Washington, D.C.: Federation of American Societies for Experimental Biology, 118–121.Google Scholar