Spinal deformation, bone quality and pododermatitis in rabbit does: effect of housing and floor type

Reproduction does (the maternal parent stock of meat rabbits) are commonly housed in individual wire floor cages. Such housing is under increased scrutiny because it is thought to restrict activity and diminish foot health. We compared individual wire cage housing (INDIWIRE) to two alternative systems: semi-group housing on a wire floor (GROUPWIRE), and semi-group housing on a plastic slatted floor (GROUPPLAST). In the roofless, 2 m2 semi-group housing pens, 4 does were housed communally during half of each 42-day long reproduction cycle (to increase the opportunity and incentive for activity). The pens were separated into 4 individual units during the other half of each cycle (around kindling, when aggression peaks). We used 6 GROUPWIRE and 6 GROUPPLAST pens. The 24 individual cages had a floor area of 0.4 m2 and were 63 cm high at the highest point. All systems were equipped with a platform. Hycole does (29 weeks old) were allotted randomly to the systems 3 da ys before their 2nd kindling, and stayed within treatment until after the weaning of the 5th litter when we collected our data. We expected semi-group housing to decrease the prevalence of spinal deformations (scoliosis, kyphosis and lordosis, assessed by post-mortem X-rays) due to increased activity. However, we found no difference between the systems (binomial: F2,62=0.4, P=0.68) although overall prevalence was high (38%). In contrast, the greater tibia cortex thickness in the semi-group pens did suggest that activity was increased in these systems (ANOVA: F2,62=3, P=0.05, LSMEANS ± SEM: 1.45, 1.46 and 1.38 mm ± 0.03, for GROUPWIRE, GROUPPLAST, and INDIWIRE, respectively). Plastic flooring was expected to decrease pododermatitis, but true ulcerative pododermatitis was absent in our study (likely due to relatively young age of the does and the application of footrests to the wire floors). However, the prevalence of plantar hyperkeratosi s (a very early stage of pododermatitis characterized by hair loss and callus formation) was much lower on the plastic floor (GROUPPLAST: 5% ± 8) than on the wire floor (65% and 68% ± 9 for GROUPWIRE and INDIWIRE, respectively, binomial: F2,62=12, P<0.0001). In conclusion, both semi-group housing and plastic flooring had a positive effect on one of our indicators. The exact impact on welfare requires further study because little is known about the progression of plantar hyperkeratosis into ulcerative pododermatitis and because the underlying reason for the suggested increased activity is unknown (i.e., it may be due to fleeing from aggressive pen mates).