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Genetic evaluation of productive life in Iranian Holstein using survival analysis

Published online by Cambridge University Press:  23 November 2017

M. Dadpasand Taromsari ,
S. R. Miraei-Ashtiani ,
M. Moradi Shahrebabak  and
R. Vaez Torshizi
M. Dadpasand Taromsari
Affiliation:
Dept. Animal Science, Faculty of Agriculture, University of Tehran, Karaj, Iran
S. R. Miraei-Ashtiani
Affiliation:
Dept. Animal Science, Faculty of Agriculture, University of Tehran, Karaj, Iran
M. Moradi Shahrebabak
Affiliation:
Dept. Animal Science, Faculty of Agriculture, University of Tehran, Karaj, Iran
R. Vaez Torshizi
Affiliation:
Faculty of Agriculture, University of Tarbiat Modarres, Tehran, Iran
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Extract

Improvement of herd life increases profitability due to lower replacement costs of heifers, higher proportion of mature cows that produce at their maximum potential and increased opportunity for voluntary culling. Functional productive life (PL) after adjustment for production is the ability of a cow to remain healthy and delay involuntary culling (Ducrocq et al 1988). Survival or failure time analysis has replaced linear model approaches for routine genetic evaluation of dairy cattle in several countries (Sewalem et. al. 2003). It allows proper treatment of censored data, inclusion of time-dependent covariates and skewed or non normal distribution of data. Approximate estimates of the heritability of longevity traits typically range from 0.05 to 0.10 and 0.15 to 0.20 using linear models and survival analysis, respectively (Vollema et al. 2000 and Caraviello et. al. 2004). The objective of this study was to apply survival analysis methodology for assessing the most important factor influencing PL, estimation of genetic parameters of productive life and genetic evaluation in Iranian Holstein dairy cattle.

Type
Poster Presentations
Information
Proceedings of the British Society of Animal Science , Volume 2005 , 2005 , pp. 131
Copyright
Copyright © The British Society of Animal Science 2005

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References

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