Analysis of rabbit doe longevity using a semiparametric log-Normal animal frailty model with time-dependent covariates
© INRA, EDP Sciences 2006
Received: 27 May 2005
Accepted: 4 January 2006
Published: 26 April 2006
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.
Keywordslongevity in rabbit does semiparametric log-Normal frailty model survival analysis time dependent covariates
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