Heterosis for Preweaning Litter Characteristics in Nigerian Rabbit Crosses

The study investigated heterosis effects for preweaning litter characteristics using three Nigerian localrabbits (Local White LW, Local Brown Tail LBT, Local Black LB). The percent heterosis for litter size inLW x LB crossbred kits was positive at the 7th, 14th and 21st day postpartum (+24.20%, +31.63% and+22.94%, respectively). Direct heterosis and percent heterosis were negative for litter size in LW x LBTand LBT x LB crosses from birth to 21-day post-partum. A positive percent heterosis of 19% wasrecorded for litter size in LW x LB crossbred kits from birth to 21-day post-partum. Mortality within litterin LW x LBT and LBT x LB crossbred kits was reduced by 159% and 125%, respectively. Heterosiseffect for litter weight (birth to 21-day postpartum) was 11% for LW x LB crossbred kits. Estimates ofdirect heterosis (and percent heterosis) for average kit birth weights were favourable for crossbred kits inthis study. The potential of crossbreeding to tap the non-additive genes for reproductive performance wasconfirmed in the present study. Crossing LW with LB resulted in positive heterosis for postbirth litter sizeand litter weight while LW x LBT and LBT x LB helped to improve preweaning mortality and averagekits’ weight.