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Response to selection for multiple births in the Australian Merino: a progress report

Published online by Cambridge University Press:  01 February 1962

Helen Newton Turner ,
R. H. Hayman ,
L. K. Triffitt  and
R. W. Prunster
Helen Newton Turner
Affiliation:
Commonwealth Scientific and Industrial Research Organisation, Australia
R. H. Hayman
Affiliation:
Commonwealth Scientific and Industrial Research Organisation, Australia
L. K. Triffitt
Affiliation:
Commonwealth Scientific and Industrial Research Organisation, Australia
R. W. Prunster
Affiliation:
Commonwealth Scientific and Industrial Research Organisation, Australia
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Extract

Results of two-way selection for multiple births are reported, in a flock of Australian Merinos.

Base ewes, selected for having multiple or single births at each of two lambings at 5 and 6 years of age have shown a good repeatability, the T group (multiple-bearers) having averaged 31 more lambs per 100 ewes mated than the O group (single-bearers) for 6 subsequent lambings.

Unselected daughters of the base ewes, now ranging in age from 2 to 6 years, have also shown a difference in lamb drop, those in the T group averaging 21 more per 100 ewes mated. The difference in lamb drop has increased with the age of the daughter ewes, reaching 31 lambs per 100 ewes mated at 6 years of age.

A small group of Merino ewes from a property where selection for multiple births is practised has produced 1·60 lambs per ewe mated at 2 and 3 years of age.

It is suggested that earlier low estimates of heritability for the incidence of multiple births have led to unwarranted pessimism, and that in some circumstances selection for multiple births may be successful.

Type
Research Article
Information
Animal Production , Volume 4 , Issue 1 , February 1962 , pp. 165 - 176
Copyright
Copyright © British Society of Animal Science 1962

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