Analysis of factors influencing longevity of rabbit does

A survival analysis, using a Cox proportional hazard model, was carried out to show the factors influencing longevity of the does in a selection nucleus. It was shown that the year-season, the combination between number of live born and reproductive rhythm, the combination between kindling order and reproductive rhythm and the age of the doe at first mating significantly affected doe longevity. Once the significant factors were known, the model was extended, including the sire effect and the maternal grandsire effect, to estimate the additive variance of the trait. This estimate was 0.088. Finally, to evaluate the effects of factors influencing longevity, an animal model was used, with the additive variance estimated previously. Inclusion of longevity as a selection criterion in rabbits does not seem advisable due to its low heritability; the trait is only recorded in females; the live females have the trait censored and its consideration makes the generation interval longer. An alternative could be developing new strains of rabbits by applying very high selection intensities in commercial populations, similar to the schemes successfully applied in pigs and rabbits. (C) 2004 Elsevier B.V. All rights reserved.