Heritability of 90-day Body Weight in Domestic Rabbits from Tropical Ghana, West Africa

Individual 90-day body weight data were collected from 687 rabbits representing 61 sire and 194 dam families from a randomly mating population in tropical Ghana, West Africa. The population was based on crosses made between 1972 and 1984 involving 15 imported breeds with the local strain. Two consecutive generations (born in 1989 and 1990) of rabbits were analyzed by mixed model procedures. Approximations of restricted maximum likelihood estimates of the observational variance components corresponding to sire, dam within sire, and residual random effects were obtained employing a mixed model that also included the fixed effects of age group, litter size at 21 days of age (linear covariate), and sex of rabbit. From these estimates were determined the respective first-and second-generation fractions of additive genetic variance (corresponding to heritabilities below), as well as the lower limits (zero for dominance genetic and residual environmental variances, but 0.02 and 0.05 for common environmental variance) and upper limits for dominance genetic (0.57 and 0.52), common (0.16 and 0.18), and residual (0.43 and 0.39) environmental causal variance components (assuming no epistatic interaction variance). Paternal half-sib estimates of heritability for the first and second generations were 0.41 ± 0.19 and 0.43 ± 0.18; a pooled estimate of 0.42 was computed. These results suggest that a breeding strategy employing individual selection for increasing individual 90-day body weight should be effective in this rabbit population.