Document Detail


The accuracy of seven mathematical functions in modeling dairy cattle lactation curves based on test-day records from varying sample schemes.
MedLine Citation:
PMID:  16606753     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Daily milk yield over the course of the lactation follows a curvilinear pattern, so a suitable function is required to model this curve. In this study, 7 functions (Wood, Wilmink, Ali and Schaeffer, cubic splines, and 3 Legendre polynomials) were used to model the lactation curve at the phenotypic level, using both daily observations and data from commonly used recording schemes. The number of observations per lactation varied from 4 to 11. Several criteria based on the analysis of the real error were used to compare models. The performance of models showed few discrepancies in the comparison criteria when daily or 4-weekly (with first test at days in milk 8) data by lactation were used. The performance of the Wood, Wilmink, and Ali and Schaeffer models were highly affected by the reduction of the sample dimension. The results of this work support the idea that the performance of these models depends on the sample properties but also shows considerable variation within the sampling groups.
Authors:
A M Silvestre; F Petim-Batista; J Colaço
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  Journal of dairy science     Volume:  89     ISSN:  1525-3198     ISO Abbreviation:  J. Dairy Sci.     Publication Date:  2006 May 
Date Detail:
Created Date:  2006-04-11     Completed Date:  2006-07-13     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  2985126R     Medline TA:  J Dairy Sci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1813-21     Citation Subset:  IM    
Affiliation:
Departement of Animal Science-CECAV, University of Trás-os-Montes e Alto Douro, 5001-801 Vila Real, Portugal. asilvest@utad.pt
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MeSH Terms
Descriptor/Qualifier:
Animals
Cattle / physiology*
Female
Lactation / physiology*
Mathematics
Models, Biological*
Regression Analysis
Sensitivity and Specificity

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


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