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ABSTRACT:The aim of the experiment was to examine the effect of group size and stocking density on productive, carcass and meat quality traits. The trial was conducted using 230 Pannon white rabbits weaned at 5 weeks and reared until the age of 11 weeks. Seven groups were formed with different cage/pen sizes (group size) and stocking densities: SC16=small cage (0.12 m 2 ), 16 rabbits/m 2 (2 rabbits/cage); LC16=large cage (0.50 m 2 ), 16 rabbits/m 2 (8 rabbits/cage); LC12=large cage, 12 rabbits/m 2 (6 rabbits/cage); SP16=small pen (0.86 m 2 ), 16 rabbits/m 2 (13 rabbits/ cage); SP12=small pen, 12 rabbits/m 2 (10 rabbits/cage); LP16=large pen (1.72 m 2 ), 16 rabbits/m 2 (26 rabbits/cage); LP12=large pen, 12 rabbits/m 2 (20 rabbits/cage). Stocking density did not affect production signifi cantly, as stocking densities lower than 16 rabbits/m 2 had no effect on the growing rabbits' performance. Group size (size of the cage or pen) had an effect on certain growth, carcass and meat quality traits. Increasing group size resulted in lower values for weight gain (SC: 39.2>LC: 39.0> SP: 38.7> LP: 37.8 g/d; P=0.22) and body weight (SC: 2506>LC: 2498> SP: 2487> LP: 2446 g; P=0.35), similarly to other results in the literature, but the differences were not signifi cant. Aggressive behaviour was observed to be more frequent in the larger group sizes. At the age of 11 weeks the proportion of rabbits with ear lesions in the SC, LC, SP and LP groups were 0.0, 7.1, 8.7, and 17.4%, respectively, demonstrating that larger group size increases the risk of ear lesions. The effect of group size on the ratio of the fore part to the reference carcass (SC: 28.5, LC: 28.2, LP: 29.0%; P=0.02) and on the amount of perirenal fat (SC: 21.3, LC: 18.0, LP: 13.7 g; P<0.001) was signifi cant. Meat quality traits (dry matter, protein, fat and ash content, drip loss, pH, L*, a*, b* values) were not affected by group size (cage vs. pen), but successful discriminations were performed using the NIRS method.

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Four experiments are described relating to gnawing sticks application in rabbit housing. In experiment 1 and 2, Pannon White rabbits, weaned at the age of five weeks, were placed into pens with wire net floor. In experiment 1, every pen (180 animals in 12 pens, surface per head: 571 cm 2 ) was provided with three gnawing sticks randomly chosen from White locust, Black elder, White willow, Little-leaf linden, European larch, Black poplar, European white birch, White buckeye and White mulberry species. In experiment 2 (150 animals in 10 pens, surface per head: 571 cm 2 ), only those tree species ingested by rabbits in the first experiment were used (White locust, White willow, Little-leaf linden, Black poplar and White buckeye). In the second experiment, rabbits showed the highest preference towards gnawing sticks of Little-leaf linden, while similar White willow and White buckeye consumption was observed. In the experiment 3, rabbits' preference to different types of wood and the influence on rabbits' behaviour of added wooden sticks as environmental enrichment was studied. At the age of 38 days, 48 male SIKA rabbits were housed individually in wire cages (surface per head: 1500 cm 2 ). According to the type of wood placed in the cage, rabbits were equally allotted to four groups: control, Common oak, Little-leaf linden and Norway spruce. Rabbits' preference to type of wood was studied on all the animals with wooden stick, while rabbits' behaviour was studied on 16 focus animals at the age of 5 and 13 weeks using continuous 24 hours video recordings. Rabbits preferred gnawing Little-leaf linden and Norway spruce compared to Common oak. Addition of gnawing sticks had no significant influence on duration of rabbits' behaviour, except for eating feed and gnawing wooden stick time. In experiment 4, the effect of housing and environmental enrichment on the performance and behaviour of growing rabbits was tested. 72 hybrid rabbits were housed after the weaning period in standard fattening cages at 2, 3, 4 animals per cage (surface per head: 1045 cm 2 , 697 cm 2 , 522 cm 2 , respectively). Half cages were enriched using a wood stick (Robinia pseudoacacia) dangling from the ceiling of the cage. The environmental enrichment decreased the stereotypies (gnawing the bars of the cage). A tendency to lower aggressive behaviours in enriched caged rabbits was also found compared to the conventional caged rabbits. This might indicate a better satisfaction of the behavioural needs for the enriched caged rabbits.