Performance of purebred and crossbred rabbits in Australia: Individual growth and slaughter traits

Abstract

Data from 3 rabbit breeds, namely New Zealand White (N), Californian (C), and Flemish Giant (F), and their crosses, i.e. CN, FN, F(CN), and C(FN), were analysed for individual growth traits such as body weights at 5 (5WT), 6 (6WT), 7 (7WT), 8 (8WT), 9 (9WT), and 10 (10WT) weeks of age, and post-weaning average daily gain between 5 and 10 weeks of age (ADG), and individual slaughter traits such as liveweight at slaughter (SW), carcass weight (CW), and dressing percentage (DP). Data included records for individual body weights from 1345 to 1524 rabbits from 279 litters and records for slaughter traits from 919 rabbits from 245 litters. Significant sources of variation for individual growth and slaughter traits were breed, parity, month-year of birth, sex, and number weaned per litter (NW). However, parity and NW did not significantly affect ADG and DP. Slaughter traits were not significantly affected by sex. The overall least squares means for 5WT, 6WT, 7WT, 8WT, 9WT, 10WT, ADG, SW, CW, and DP were 836 g, 1021 g, 1215 g, 1390 g, 1577 g, 1791 g, 27.2 g/day, 2.28 kg, 1.23 kg, and 53% respectively. N and F purebred, and FN crossbred rabbits performed significantly (P < 0.05) better than C purebred and crossbreds [CN and C(FN)] in all the individual growth and slaughter traits except for DP. CN performed better (P < 0.05) in DP than all other crosses. ADG of C rabbits was significantly (P < 0.05) lower than of all other crosses under study, with F(CN), C(FN), and CN crosses showing intermediate growth rates. Significantly (P < 0.05) higher growth rates were observed in N, F, and FN breeds. There was no significant heterosis observed in the breed crosses for any traits under study. Individual body weights at 5–10 weeks of age were significantly lower in the 1st parity born rabbits than in other higher parity born rabbits. SW and CW were significantly higher in 2nd and 3rd parity rabbits than in 1st and 4th and later parity born rabbits. Female rabbits achieved heavier weights at 5, 6, and 7 weeks of age than males and males weighed more than females after 7 weeks of age. ADG of males was significantly (P < 0.05) higher than of females. Significant negative regression coefficients of NW on all individual body weights until slaughter age showed that larger litters had lighter rabbits. Coefficient of variation for individual growth and slaughter traits ranged between 11.1 and 20.7%. Common litter variance explained a significantly large proportion of total phenotypic variance, with the proportions ranging between 0.36 and 0.55 for individual growth traits, 0.46 for SW, and 0.35 for CW.