Claw loading in dairy cows with different hind-limb postures

Introduction
Limb posture and limb conformation are important aspects of claw trimming and are discussed as possible factors in the occurrence of claw horn lesions. The objective of our study was to measure forces and pressures acting on the hind claws of cows with different hind-limb conformation. 

Materials and Methods
Thirty-nine non-lame lactating dairy cows consisting of 3 different breeds were assigned by two observers to one of 4 groups of hind limb conformation. Of these cows, 12 had normal conformation, 12 were cow-hocked, 12 were straight-legged, and 3 were bow-legged. Functional foot trimming was done before the measurements. Vertical ground reaction forces, sole imprint areas, and mean and maximum pressures were measured using a platform containing a force plate, which was connected to a pressure plate, an interface box, and a PC. Both hind feet were measured simultaneously in square-standing cows. 

Results
There were only a few significant differences among the different groups in the distribution of forces, pressures, and contact areas. In all cows and regardless of limb conformation, the lateral claw and its heel region always carried significantly more weight than the medial claw and its heel region. The load on the lateral claws was highest in bow-legged cows (80 % of the limb vGRF), but the small number of these cows precluded statistical analysis. 

Conclusions
These findings suggest that limb conformation does not have a major influence on load distribution between hind limb claws in cattle. Improvement of claw health should therefore focus more on stall design, e.g. the design of cow-friendly barn flooring, rather than on genetic selection for hind-limb conformation. However, further studies using an objective conformation grading system and a larger number of cows are possibly needed to corroborate the validity of our results.