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 mechanicaloverload is an important contributor to claw tissue damage and impaired locomotion, deformation andclaw injury as a result of mechanical loading has been poorly quantified and, as a result, practical solutionsto reduce such lesions have been established mostly through trial and error. In this study, anexperimental technique was developed that allowed the measurement under controlled loading regimesof minute deformations in the lower limbs of dissected specimens from large ungulates. Roentgenstereophotogrammetric analysis (RSA) was applied to obtain 3D marker coordinates with an accuracyof up to 0.1 mm with optimal contrast and to determine changes in the spatial conformation. A forceplate 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 thatsmall load-induced deformations and translations as well as small changes in centres of force applicationcould be measured. Accuracy of the order of 0.2–0.3mm was feasible under practical circumstanceswith suboptimal contrast. These quantifications of claw deformation during loading improve understandingof 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 ofspecimens and circumstances