Effect of body fatness and selection for prolificacy on survival of rabbit does assessed using a cryopreserved control population

The aim of this experiment was to investigate the effect of body condition and selection for prolificacy on the reproductive life span of female rabbits. The body condition was obtained by ultrasound measurement of the perirenal thickness of 166 crossbred does at day 10 after parturition in 6 consecutive parities. Two genetic groups were included: the current generation of does crossbred between two lines, both selected within line for number of pups at weaning, and a control group consisting of animals from the same cross but from 12 generations earlier. This control population was obtained by use of cryopreservation techniques, and made a simultaneous comparison between animals of different generations possible. A proportional Cox model was used to obtain estimates of survival characteristics. Twelve generations of selection for litter size at weaning did not significantly affect reproductive life span. Animals in poor body condition were found to have a significantly (P < 0.05) higher risk of dying than animals in better condition. Also, animals with high body fat mobilisation had a higher risk of culling (P < 0.05) than animals with intermediate mobilisation. Animals with zero pups born alive were also found to have a high risk of culling (P < 0.001).