A new technique using roentgen stereophotogrammetry to measure changes in the spatial conformation of bovine hind claws in response to external loads

Claw and locomotion problems are widespread in ungulates. Although it is presumed that mechanical
overload is an important contributor to claw tissue damage and impaired locomotion, deformation and
claw injury as a result of mechanical loading has been poorly quantified and, as a result, practical solutions
to reduce such lesions have been established mostly through trial and error. In this study, an
experimental technique was developed that allowed the measurement under controlled loading regimes
of minute deformations in the lower limbs of dissected specimens from large ungulates. Roentgen
stereophotogrammetric analysis (RSA) was applied to obtain 3D marker coordinates with an accuracy
of up to 0.1 mm with optimal contrast and to determine changes in the spatial conformation. A force
plate was used to record the applied forces in three dimensions.
The results obtained for a test sample (cattle hind leg) under three loading conditions showed that
small load-induced deformations and translations as well as small changes in centres of force application
could be measured. Accuracy of the order of 0.2–0.3mm was feasible under practical circumstances
with suboptimal contrast. These quantifications of claw deformation during loading improve understanding
of the spatial strain distribution as a result of external loading and the risks of tissue overload.
The method promises to be useful in determining load–deformation relationships for a wide variety of
specimens and circumstances.