Behaviour of growing rabbits under various housing conditions

The aim of this research was to assess the effects of environmental variables (group size, stocking density, floor type, environmental enrichment) on behaviour - as a welfare indicator - of growing rabbits. Two experiments were carried out with Parmon White rabbits. In experiment 1, 5-week-old rabbits (n = 112) were placed in cage blocks (2 m(2)) with a stocking density of 16 or 12 rabbits/m(2). The cages (0.5 m(2)) differed in the floor type (wire or plastic net) and in the presence or absence of gnawing sticks (white locust). The animals could move freely among the four cages through swing doors. Infrared video recording was performed once a week, the number of rabbits in each cage was counted every half an hour (48 times/day) during the 24 h video recording. Between ages 5 and 11 weeks the rabbits showed a preference towards the plastic net floor (16 rabbits/m(2), 62.5%; 12 rabbits/m(2), 76:5%; P < 0.001). Gnawing stick application significantly affected cage preference: 54.1% (16 rabbits/m(2)) or 53.1% (12 rabbits/m(2)) of the rabbits choose the enriched cages (P < 0.001). In experiment 2, the 5-week-old rabbits were placed either in cages (2 rabbits/0.12 m(2), n = 72) or pens (13 rabbits/0.86 m(2), n = 104) with 16 rabbits/m(2). The floor types were wire or plastic net, with the presence or absence of gnawing sticks on the walls. Video recordings were made at 6.5 and 10.5 weeks of age between 11:00 a.m. and 5:00 p.m. and between 11:00 p.m. and 05:00 a.m. Compared to cages, the rabbits housed in pens spent less time with resting (58% versus 67%) and more time with locomotion (6.7% versus 3.8%) but the frequency of aggressive behaviour (measured by the number of ear lesions) was also higher (0.14% versus 0.01%). In pens the application of gnawing sticks significantly decreased the frequency of ear injuries (0.05% versus 0.22%). The floor type did not affect any behavioural pattern (eating, drinking, movement, resting, comfort, social, investigatory) significantly. The main results showed that growing rabbits have a preference for plastic net floor and cages provided with gnawing sticks. The resting, locomotive and aggressive behaviour was modified by the housing system and the presence of gnawing sticks decreased the frequency of physical injuries.