Effect of outdoor grazing-area access time and enrichment on space and pasture use, behaviour, health and growth traits of weaned rabbits.

Providing rabbits with a grassy outdoor area allows them to express a broad variety of specific behaviours such as grazing where grazeable herbage persists. However, rabbits that graze are also exposed to external stressors. Controlled outdoor access time may help preserve the grassland resource, while a hiding place may offer the rabbits a secure space. We focused on rabbit growth, health and behaviour according to outdoor access time and the presence of a hideout on a 30-m2 pasture area. We divided 144 rabbits into four groups (group of rabbits with 8 hours per day (H8) of access to pastures provided with an hideout (Y) (H8Y): n = 36; group of rabbits with 8 hours per day (H8) of access to pastures unprovided with an hideout (N) (H8N): n = 36; group of rabbits with 3 hours per day (H3) of access to pastures provided with an hideout (Y) (H3Y): n = 36; group of rabbits with 3 hours per day (H3) of access to pastures unprovided with an hideout (N) (H3N): n = 36) that differed in access time (H8, four replicates, eight hours a day from 0900 h to 1700 h; and H3, four replicates, three hours a day from 0900 h to 1200 h) and the presence of a hideout (presence of an hideout on the pasture (Y), four replicates, with a roof-shaped wooden hideout; and absence of an hideout on the pasture (N), four replicates, without). Rabbit growth and morbidity were measured weekly for each rabbit from 34 to 76 days of age. Rabbit behaviour was assessed on days 43, 60 and 74 by direct visual scanning. Available grassy biomass was evaluated on days 36, 54 and 77. We also measured the time rabbits took to enter and exit the mobile house and the level of corticosterone accumulated in their hair during the fattening period. There were no between-group differences in live weight (on average, 2 534 g at 76 days of age) and mortality rate (18.7%). The rabbits expressed a broad variety of specific behaviours, with grazing being the most frequent (30.9% of all the observed behaviours). Foraging behaviours including pawscraping and sniffing were more frequently observed in H3 rabbits than H8 rabbits (1.1 vs 0.3% and 8.4 vs 6.2%, respectively; P < 0.05). There was neither an access-time nor hideout presence effect on rabbit hair corticosterone levels or time to exit and enter the pens. Patches of bare ground were more frequent in H8 pastures than in H3 pastures (26.8 vs 15.6%, respectively; P < 0.05). Over the whole growing period, the biomass intake rate was higher in H3 than H8 and higher in N than Y (1.9 vs 0.9 g/rabbit/h and 1.8 vs 0.9 g/rabbit/h, respectively; P < 0.05). In conclusion, restricted access time tended to slow the reduction of the grass resource but had no detrimental effects on rabbit growth or health. Rabbits facing restricted access time adapted their grazing behaviour. A hideout helps rabbits cope with external stressors.

Effect of access to outdoor grazing and stocking density on space and pasture use, behaviour, reactivity, and growth traits of weaned rabbits.

In a context of evolving concern over housing conditions of farmed rabbits, we developed a housing system that allows access to an outdoor area. The aim was to study the health status, growth and behaviour of rabbits raised at two stocking densities with access to a paddock, or not. We distributed 299 weaned rabbits in four groups (YH: 100, NH: 99, YL: 50 and NL: 50) using a 2 × 2 factorial design including access (Y: yes) or not (N: not) to a 23 m2 paddock and the indoor stocking density (H, high: 17 or L, low: 9 rabbits/m2). We measured the growth and health status of each animal weekly for 42 days (from 31 to 73 days of age) and performed reactivity tests to a new environment, a human and new object. We also assessed the rabbits' behaviour at days 26 and 40 by doing a visual scan of each animal at regular time intervals. Our results showed that stocking density had no effect on mortality, but mortality tended to increase with outdoor access from 3.0% to 7.0% (P < 0.10). Although the stocking density had no effect on average daily gain, it was higher in rabbits in the N group than in the Y group (+3.6 g/day; P < 0.05). Rabbits entered the paddocks for the first time in less time at the beginning of the trial (50 s at day 3 vs 10 min at day 31; P < 0.001). The proportion of rabbits outside after 20 min of the new environment test was higher among rabbits in the L group than in the H group (+24% points at day 3 and +11% points at day 20; P < 0.001). Regardless of the stocking density, more rabbits in the N group touched the experimenter's hand (16% vs 27%; P < 0.05) and the new object (34% vs 20%; P < 0.05) than rabbits in the Y group. Inactivity was more frequent in rabbits inside the pens than in the paddocks (70.0% vs 34.2% at days 26 and 40; P < 0.05). Locomotion was more frequent in the paddocks than in the indoor pens (20.0% vs 7.2% at days 26 and 40; P < 0.05). The stocking density did not affect the behavioural traits measured. In conclusion, providing rabbits access to a paddock could allow them to fulfil some natural behaviours but slightly reduced their growth.