Document Detail


Heifer fertility in Norwegian dairy cattle: variance components and genetic change.
MedLine Citation:
PMID:  12939095     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Variance components and genetic change were estimated for 56-d nonreturn rate in virgin heifers using first insemination records of a total of 1,632,961 Norwegian Dairy Cattle daughters of 2945 sires. Six univariate mixed linear sire models were compared. The heritabilities varied from 1.2% to 1.4%. All models gave favorable, although different, estimates of genetic change of 56-d nonreturn rate. The method used to validate the genetic trend did not detect bias in any of the models. Goodness-of-fit and predictive ability were used to further validate the models. Three models included service sire, but this effect had little influence on the results. Models treating the herd-year effects as random showed smaller prediction error and higher correlation between observed and predicted values than the models treating herd-year effect as fixed. To avoid confounding of environmental and genetic effects, the model including fixed effect of month-year was preferred over a model with only month of first insemination to estimate the genetic change. Female fertility has been successfully included in the total merit index of Norwegian Dairy Cattle for 20 yr. This has resulted in genetic improvement and the chosen model showed annual genetic change of 0.04% for 56-d nonreturn rate in heifers between 1979 and 2000.
Authors:
I M A-Ranberg; B Heringstad; G Klemetsdal; M Svendsen; T Steine
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Validation Studies    
Journal Detail:
Title:  Journal of dairy science     Volume:  86     ISSN:  0022-0302     ISO Abbreviation:  J. Dairy Sci.     Publication Date:  2003 Aug 
Date Detail:
Created Date:  2003-08-26     Completed Date:  2004-04-27     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  2985126R     Medline TA:  J Dairy Sci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2706-14     Citation Subset:  IM    
Affiliation:
Department of Animal Science, Agricultural University of Norway, Box 5025, N-1432 As, Norway. ina.ranberg@ihf.nlh.no
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MeSH Terms
Descriptor/Qualifier:
Animals
Breeding*
Cattle / genetics,  physiology*
Female
Fertility / genetics*
Genetic Variation*
Lactation / genetics
Linear Models
Models, Genetic*
Norway
Predictive Value of Tests

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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