Analysis of incidence of pre and post mature gestations in rabbit populations

Records of 5043 parturitions from two commercial breeds of rabbits (2724 Bauscat and 2319 New Zealand White) were analyzed to investigate the productive and reproductive traits as affected by gestational type (pre-mature, full term or post-mature). The genetic and environmental factors affecting gestation length were also studied. The total incidence of pre-and post-mature doe were 1.6 and 31 \%, respectively. The incidence of overdue does were decreased as litter size at birth increased. Full term does showed a reproductive performance superior to the predate and overdue does, having a higher overall litter size and mass at birth. Estimates of paternal halfsib heritability for gestation length were very low and repeatability were found to be slightly higher. Litter size appears to be the major non-genetic factor affected on incidence of pre and post mature.