Heritability estimates and genetic correlations of some reproductive traits in heterogeneous rabbit population in South-west Nigeria

Litter records of fifty six adult rabbits from heterogeneous rabbit population were used to estimate heritability (h2) and genetic correlations of some litter traits at birth, weaning and at 12- weeks of age. Forty-nine does were randomly allocated to seven sire families and the sire component of variance with unequal numbers of offspring per family was used to estimate heritability. Data were analysed using the General Linear Mixed Model procedure of SAS via Restricted Maximum Likelihood Method. Variance and Covariance Component Estimation Procedure were used to calculate h2 and genetic correlation respectively. Results showed that, Heritability estimates (h2) for body weight (BWT), litter birth weight (LBW) and litter size at birth (LSB) were 0.02, 0.19 and 0.20 respectively. The corresponding estimates at weaning were 0.02, 0.09 and 0.23 respectively. The h2 for individual weight and litter size at 12- week (LS12) were 0.46 and 0.06 respectively. Genetic correlation coefficients were generally positive for weekly body weight from birth to 12-week and ranged from low (0.09) to very high (1.00). The LBW and litter weaning weight (LWW), LBW and litter size at weaning (LSW) and LSW and LWW had genetic correlation coefficients of 0.87, 0.57 and 0.86 respectively. It was concluded that, this heterogeneous rabbit population showed high variability in reproductive traits, indicating a high degree of heterogeneity. Heritability estimates indicated that various outbreeding mating systems and family selection will be effective for the improvement of these traits with low heritability estimates by taking advantage of heterosis (hybrid vigour) while individual selection will be effective for the improvement of body weight at 12-week for this rabbit population. Strong genetic correlations between LWW and LBW in this rabbit population showed that, selection for increased LBW will lead to a correlated increase in LWW.