Performance of growing rabbits in bicellular cages and collective pens

The study aimed at evaluating whether housing growing rabbits in pairs in bicellular cages (18 animals/m2) or in group of 20 to 54 animals kept in small (1.40 x 1.20 m) or large pens (1.40 x 2.40 m) with wooden floor at low (12 animals/m2) or high stocking density (16 animals/m2) might influence growth performance and slaughter traits. The rabbits kept in bicellular cages showed higher final live weight (2839 vs. 2655 g; P<0.01), daily weight gain (+10%; P<0.01), and feed intake (+11%; P<0.001), without differences for feed conversion ratio, compared with the rabbits housed in collective pens. At slaughter, the former rabbits also displayed higher dressing percentage (60.5% vs. 59.6%), dissectible fat proportion (3.0% vs. 2.1% reference carcass) and hind leg muscle-to-bone ratio (7.53 vs. 6.63) (P<0.001) compared with the group-housed rabbits. Within the collective pens, the increase in the stocking density from 12 to 16 rabbits/m2 increased only the slaughter dressing percentage (59.4% vs. 59.8%; P=0.05), whereas no significant effect of pen size was measured. In conclusion, rearing rabbits in collective pens impaired growth performance and slaughter results compared to rabbits kept in bicellular cages, regardless of stocking density or pen size.