Genet. Sel. Evol. 38 (2006) 281-295
DOI: 10.1051/gse:2006004

Analysis of rabbit doe longevity using a semiparametric log-Normal animal frailty model with time-dependent covariates

Juan Pablo Sánchez^a, Inge Riis Korsgaard^b, Lars Holm Damgaard and Manuel Baselga<sup>b

a</sup>  Departamento de Ciencia Animal, Universidad Politécnica de Valencia, Camino de Vera 14, 46022 Valencia, Spain
^b  Department of Genetics and Biotechnology, Research Centre Foulum, Danish Institute of Agricultural Sciences, P.O. Box 50, DK-8830 Tjele, Denmark

(Received 27 May 2005; accepted 4 January 2006; published online 26 April 2006)

Abstract - Data on doe longevity in a rabbit population were analysed using a semiparametric log-Normal animal frailty model. Longevity was defined as the time from the first positive pregnancy test to death or culling due to pathological problems. Does culled for other reasons had right censored records of longevity. The model included time dependent covariates associated with year by season, the interaction between physiological state and the number of young born alive, and between order of positive pregnancy test and physiological state. The model also included an additive genetic effect and a residual in log frailty. Properties of marginal posterior distributions of specific parameters were inferred from a full Bayesian analysis using Gibbs sampling. All of the fully conditional posterior distributions defining a Gibbs sampler were easy to sample from, either directly or using adaptive rejection sampling. The marginal posterior mean estimates of the additive genetic variance and of the residual variance in log frailty were 0.247 and 0.690.

Key words: longevity in rabbit does / semiparametric log-Normal frailty model / survival analysis / time dependent covariates

Correspondence and reprints: juansan@dca.upv.es

© INRA, EDP Sciences 2006