Effect of breed, cage type and reproductive phase on fecal corticosterone levels in doe rabbits

Corticosterone concentration in faeces is increasingly being used as a non-invasive indicator of stress in the assessment of farm animal welfare. The aim of the present study was to evaluate the effects of breed, cage type, reproductive phase (synchronisation, artificial insemination, partum, pre-weaning, and post-weaning) and all possible interactions among these factors have upon baseline faecal corticosterone (FC) concentrations in rabbit doe. Two hundred and fifty-two rabbit does (belonging to two different breeds, a New Zealand commercial hybrid and an autochthounous Italian breed named Grigio del Monferrato) were equally randomly ascribed to two groups. The does were then individually housed in either standard dimension wire cages or in wire cages with a volume more than double that of the standard cages (0.10 m3 and 0.24 m3, respectively). The latter equipped with a foot plastic mat. Breed, cage type, and reproductive phase significantly affected FC concentrations, while none of the tested interactions was statistically significant. The New Zealand hybrid showed significantly higher FC levels when compared to the autochthonous breed. Increasing cage size coupled with the use of a foot plastic mat determined a significant lowering in doe FC concentrations. Considering the different reproductive moments, the highest FC levels were detected at partum, followed by post-weaning. No differences were found in FC concentrations among synchronization, artificial insemination and pre-weaning. Such results support the hypothesis that measurement of FC concentrations provide a useful indicator of chronic stress in rabbit does.