Estimating Additive and Dominance Variance for Litter Traits in Purebred California White Kits Using Different Models
Reproductive and growth records of 82 purebred California white kits were used to estimate additive and dominance genetic variances using BULPF90PC-PACK. Estimates were obtained for litter size at birth (LSB) and at weaning (LSW); litter weight at birth (LWB) and at weaning (LWW); individual kit weight at birth (IKWB)and at weaning (IKWW)as well as neonatal (Nil) and morlality at weaning (WM). Two mixed model equations were adopted. The first model included fixed effects and random effects identifying inbreeding depression, additive gene effect and permanent environmental effects. The second model was similar to the first model, but included the dominance genotypic effect. Estimates of heritability from sire component of variance for LSB, LSW, LWB, LWW, IKWB and IKWW were 0.4810.53,0.41/0.44, 0.5010.55 ,0.491NA, 0.4410.47 and 0.48/0.56 from model 1 and 2 respectively. Proportions of dominance effect to total phenotypic variance from the dominance model were 0.222, 0.453, 0.206, 0.349, 0.417 and 0.521 for LSB, LSW, LWB, LWW, IKWB and IKWW respectively. Dominance effects, which are not transferable through gametes (haploid entities) but are recreated at random in the offspring, were found to influence the litter traits analyzed. Therefore, genetic evaluation with the dominance model (Model 2) was found more appropriate than the animal model (Model 1).
Keywords: Additive, Dominance, Heritability, Inbreeding, Rabbit