Breeding and genetics.

Three complete diallel crosses using purebred bucks and does of four rabbit breeds (Californian, C; Chinchilla, Ch; New Zealand White, N and Semigiant White, S) were realized in different periods (1968-1970 and 2003-2004), involving 6293 preweaning records. The traits studied were: total born (TBorn), born alive (BornA), viability at birth (ViabB), number weaned (NW), proportion of weaned litters (PWL) and viability at weaning (ViabW). A generalized linear mixed model using the PROC GLMMIX of SAS was applied, which considered the fixed effects of breed of the doe and the buck (4 classes each), experiment (3 trials), doble and triple interactions between all fixed effects, and the random effect of parity (5 levels).The does from breeds S and N excelled the others in viabilities and NW, while the bucks from N breed showed disadvantages in viabilities. The interaction effect between the doe and buck breeds identified the best crosses for NW, as SN, SCh and CS, over NCh, and C. The dam and sire breeds*experiment interactions were significant for ViabB, NW and ViabW. Differences between the breed of the doe were only found in experiment 1 and 2 with advantages for the N doe breed. The effect of buck breed was only significant in experiment 2, for ViabB, where C excelled N, and in ViabW the S breed excelled the rest. The triple interaction was significant in ViabW. It showed the best correspondence in merit order between experiment 1 and 3 with correlations of 0.5. The best three crosses across experiments were: SN, ChS, and ChN, which, along with the CS cross and the S and N dam breeds are recommended for commercial crossbreeding schemes.