Genet. Sel. Evol.
Volume 38, Number 4, July-August 2006
|Page(s)||359 - 370|
|Published online||23 June 2006|
Variance components for survival of piglets at farrowing using a reduced animal modelIan M.S. Whitea, Rainer Roeheb, Pieter W. Knapc and Sue Brotherstonea, b
a Institute of Evolutionary Biology, University of Edinburgh, Ashworth Laboratories, West Mains Road, Edinburgh EH9 3JT, UK
b Sustainable Livestock Systems Group, Scottish Agriculture College, Bush Estate, Penicuik, Midlothian EH26 0PH, UK
c PIC International Group, Ratsteich 31, D-24837 Schleswig, Germany
(Received 16 August 2005; accepted 20 February 2006; published online 23 June 2006)
Abstract - Farrowing survival is usually analysed as a trait of the sow, but this precludes estimation of any direct genetic effects associated with individual piglets. In order to estimate these effects, which are particularly important for sire lines, it is necessary to fit an animal model. However this can be computationally very demanding. We show how direct and maternal genetic effects can be estimated with a simpler analysis based on the reduced animal model and we illustrate the method using farrowing survival information on 118 193 piglets in 10 314 litters. We achieve a 30% reduction in computing time and a 70% reduction in memory use, with no important loss of accuracy. This use of the reduced animal model is not only of interest for pig breeding but also for poultry and fish breeding where large full-sib families are performance tested.
Key words: reduced animal model / piglet survival
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© INRA, EDP Sciences 2006