The design of slatted concrete floors for liquid manure barns has traditionally leaned more heavily towards optimization of effective drainage of manure. Some of these slat designs have worked well in optimizing manure management and at the same time did not increase sow lameness where sows were housed in individual gestation stalls. Some studies have demonstrated that sows that are group-housed on slatted floors can be more prone to foot lesions than stall-housed sows on similar floors. As more sows move out of stalls and into pen gestation, a rethink on slat design for group housed sows was in order. Kinematics is a branch of mechanics that is concerned with the geometry of motion of objects. These Canadian researchers used kinematics to characterize the gait of 12 gilts and 12 lame sows walking in a corridor on slatted concrete floors with different combinations of slat (85, 105 or 125 mm) and gap (19, 22 or 25 mm) widths. (Photo 1) The nine experimental floors were tested with slats in the perpendicular and parallel orientation to the direction of animal walk, according to a duplicated lattice design. Gait parameters were quantified using spatial, temporal and angular kinematics for front and rear limbs.
The researchers found that some gait parameters were significantly affected by the treatments (p < 0.05), but the effects differed between gilts and lame sows and between slat orientations. Most of the effects were found on the front limbs which bear 60% of the body weight. Gap width had a significant effect on kinematic parameters such as back angle, stride length, foot height, and carpal and tarsal joint angle amplitudes. Slat width significantly affected parameters such as foot height, and carpal and tarsal joint angle amplitudes. The study showed a better ease of walking for the smaller gaps (19 and 22 mm), and the larger slats (105 and 125 mm).
Take Home Message
These findings are partially in agreement with the recommendation of the European Union for a maximum gap width of 20 mm but support the use of a wider slat than the EU minimum slat width of 80 mm.
Submitted by Christine Pelland, DVM
Ref: Devillers N, Janvier E, Delijani F, Méthot S, Dick KJ, Zhang Q, Connor L. Effect of Slat and Gap Width of Slatted Concrete Flooring on Sow Gait Using Kinematics Analysis. Animals (Basel). 2019 Apr 30;9(5). pii: E206. doi: 10.3390/ani9050206.\