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United States Department of Agriculture

Agricultural Research Service

Title: Performance of Holstein Clones

Authors
item Norman, H
item Lawlor, T - HOLSTEIN ASSOCIATION
item WRIGHT, JANICE

Submitted to: World Congress of Genetics Applied in Livestock Production
Publication Type: Proceedings
Publication Acceptance Date: August 19, 2002
Publication Date: N/A

Interpretive Summary: There is considerable interest recently in the impact of biotechnology on food safety, and especially cloning. Cloning by embryo splitting and nuclear transfer were introduced during the 1980s and the performance of clonal families that result from the biotechnology has yet to be examined. This study documents phenotypic and genetic performance of U.S. Holstein clones from embryo splitting and nuclear transfer for yield and fitness traits. A total of 2226 split embryo clones and 187 nuclear-transfer clones have been registered with the Holstein Association. Numbers of embryo-split males clones have decreased as has all nuclear-transfer clones. For clones to enhance the population genetically, their pedigree merit must be superior to that of the population. Animals selected for cloning were slightly superior genetically to population mean for yield traits. For females, mean superiority of pedigree merit of embryo-split clones compared with that of the population for the same birth year was 189 kg for milk, 8 kg for fat and 7 kg for protein. For nuclear-transfer clones, superiority to population pedigree merit was 278, 10 and 10 kg, respectively. The small pedigree advantage for clones of 1 standard deviation above breed mean indicates that the selection of animals to clone was not based primarily on production. Yields of embryo-split clones were slightly less than those of their full siblings, which indicates a possible impact of the technology on performance. Yields of nuclear- transfer clones were similar to those of their non-cloned full siblings.

Technical Abstract: There is considerable interest recently in the impact of biotechnology on food safety, and especially cloning. Cloning by embryo splitting and nuclear transfer were introduced during the 1980s and the performance of clonal families that result from the biotechnology has yet to be examined. This study documents phenotypic and genetic performance of U.S. Holstein clones from embryo splitting and nuclear transfer for yield and fitness traits. A total of 2226 split embryo clones and 187 nuclear-transfer clones have been registered with the Holstein Association. Numbers of embryo-split males clones have decreased as has all nuclear-transfer clones. For clones to enhance the population genetically, their pedigree merit must be superior to that of the population. Animals selected for cloning were slightly superior genetically to population mean for yield traits. For females, mean superiority of pedigree merit of embryo-split clones compared with that of the population for the same birth year was 189 kg for milk, 8 kg for fat and 7 kg for protein (P<0.001). For nuclear- transfer clones, superiority to population pedigree merit was 278, 10 and 10 kg, respectively (P<0.001). The small pedigree advantage for clones of 1 standard deviation above breed mean indicates that the selection of animals to clone was not based primarily on production. Yields of embryo- split clones were slightly less than those of their full siblings, which indicates a possible impact of the technology on performance. Yields of nuclear-transfer clones were similar to those of their non-cloned full siblings.

Last Modified: 7/25/2014
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