Survival analysis and assessment of maternal-related risk factors for mortality of rabbits in the humid tropics of Nigeria
摘要
High mortality rate of rabbits, especially during the pre-weaning stage of life, is prevalent in the tropics. This study evaluated survival patterns and identified maternal-related risk factors influencing mortality in rabbits raised under tropical conditions in Nigeria. A total of 524 rabbits were observed across four parities from birth to 56 days of age. Data were collected on survival status, survival days, parity, kit’s weight at birth (KWB), litter size at birth (LSB), doe’s weight at conception (DWC) and doe wool nesting score (DWNS). Survival analysis was conducted using Kaplan–Meier survival estimates and maternal-related risk factors associated with mortality were evaluated using Cox proportional hazards regression models. The overall survival rate was 66.41%, with the highest survival observed during the 3rd and 4th parities (73.53% and 71.55%, respectively) and the lowest during the 1st parity (54.69%). Further, early neonatal mortality accounted for 37.5% of total losses within the first five days. Significant maternal-related risk factors for mortality of kits included LSB, DWC, and DWNS. In addition, mortality risk was 40.5% higher in larger-sized litters compared to small-sized litters, likely due to increased competition for maternal resources. However, risk of mortality decreased with higher doe weight and increased nest-building score. Mortality risk reduced by 26% per 100 g increase in DWC while it reduced by 15.3% per one-category improvement in DWNS. Kaplan-Meier survival curves also revealed that survival improved across successive parities and experienced does exhibited more effective maternal behavior. Moreover, kits with higher birth weights showed higher survival probabilities compared to kits with lower birth weight. These findings highlight the need for policy frameworks that support selective breeding for key maternal traits and improved neonatal management practices to reduce mortality and enhance the sustainability of rabbit production in tropical systems.