Relative performance and efficiency of five Merino and Merino-type dam lines in a terminal crossbreeding system with Dormer or Suffolk sires

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dc.contributor.authorCloete, S. W. P. (Schalk Willem Petrus van der Merwe)
dc.contributor.authorCloete, J. J. E.
dc.contributor.authorHerselman, M. J.
dc.contributor.authorHoffman, L. C.
dc.date.accessioned2011-09-23T06:29:24Z
dc.date.available2011-09-23T06:29:24Z
dc.date.issued2004
dc.descriptionThe original publication is available at http://www.sasas.co.za/en_ZA
dc.description.abstractABSTRACT: The production performance of ewes was assessed in a terminal crossbreeding experiment involving five Merino and Merino-type dam lines and two terminal crossbreeding sire breeds. Dam lines were SA Mutton Merino (SAMM), SAMM rams crossed to Merino ewes (SAMM cross), Dohne Merino, as well as specialist Merino lines selected for clean fleece weight (FW+) and for an increased reproduction (Rep+). Dormer and Suffolk rams were used as sires. Dual-purpose ewes were heavier than Merinos on average and at the ultimate joining at 3.5 years. Average clean fleece weight for SAMM ewes was approximately half that of Merino ewes while clean fleece weights for Dohne and SAMM cross ewes were intermediate. Differences between progeny in slaughter age, marketing weight, dressing percentage and carcass weight could largely be attributed to the comparison of purebred Merino lines with dual-purpose lines. The slaughter age of lambs from the two Merino lines was between 14 and 21% higher than that of the dual-purpose lines. Lambs from purebred SA Mutton Merino (SAMM) dams also outperformed lambs from SAMM cross ewes for slaughter age, slaughter weight and carcass weight. Considerable variation was found between dam lines for reproduction parameters, but few significant differences were found. Lamb output, defined as total weight of lamb slaughtered per joining, averaged 42.7 kg for SAMM ewes, 44.2 kg for SAMM cross ewes, 39.3 kg for Dohne ewes, 32.9 kg for FW+ Merino ewes and 42.0 kg for Rep+ Merino ewes, but differences between lines only tended to be significant. Sire breed did not affect lamb performance or ewe productivity markedly. An economic simulation indicated large differences in gross income per small stock unit between dam lines, warranting further research on the efficiency of terminal Merino-type dam lines.en_ZA
dc.description.versionPublishers' versionen_ZA
dc.format.extentp. 135-143 : ill.
dc.identifier.citationCloete, S. W. P., CLoete, J. J. E., Herselman, M. J. & Hoffman, L. C. 2004. Relative performance and efficiency of five Merino and Merino-type dam lines in a terminal crossbreeding system with Dormer or Suffolk sires. South African Journal of Animal Science, 34(3), 135-143.en_ZA
dc.identifier.urihttp://hdl.handle.net/10019.1/16430
dc.language.isoen_ZAen_ZA
dc.publisherSouth African Society for Animal Scienceen_ZA
dc.rights.holderSouth African Society for Animal Scienceen_ZA
dc.subjectCarcass yielden_ZA
dc.subjectFibre diameteren_ZA
dc.subjectGross incomeen_ZA
dc.subjectLamb outputen_ZA
dc.subjectProductivityen_ZA
dc.subjectReproductionen_ZA
dc.subjectWool yielden_ZA
dc.subjectMerino sheep -- Breedingen_ZA
dc.titleRelative performance and efficiency of five Merino and Merino-type dam lines in a terminal crossbreeding system with Dormer or Suffolk siresen_ZA
dc.typeArticleen_ZA
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