Measurements of claw dimensions in cows before and after functional trimming: a post-mortem study.

The aim of this study was to compare measurements of the medial and lateral claws of the hind feet in cattle, and to establish reference values to aid in functional claw trimming. Variables of the medial and lateral claws of 40 hind feet obtained from 40 slaughtered German Simmental cows were measured. To standardise the observations the soles of both the medial and lateral claws were first trimmed to a defined thickness of 5mm at the apex and 8mm at the heel, before measurements were taken. After this standardisation, the mean lengths of the dorsal walls of the two claws were not significantly different (means, lateral 76.8, medial 77.1 mm). However, there were considerable other differences. For example, the soles of the lateral claws were significantly (P < 0.01) longer (means, 120.1mm versus 112.7 mm, and wider (means, 52.0 mm versus 42.5 mm). In 36/40 feet, the sole of the lateral claw protruded approximately 2-3mm above the sole of the medial claw after the standardisation. The soles of the lateral claws were therefore then trimmed to the height of the medial claw ("levelling") and the measurements were repeated in the lateral claws. The dorsal wall of the lateral claw was then significantly shorter than that of the medial claw (means, 74.8 mm versus 77.1 mm) and, most importantly from a functional point of view, the sole was significantly thinner than that of the medial claw (means, 2.71 mm versus 5mm at the toe tip, 4.9mm versus 8 mm at the heel). Finally, the horn capsule of all claws was removed and various measurements of the corium surface were made. The length of the dorsal corium surface did not differ statistically (P > 0.05) between the lateral (mean, 62.6 mm) and medial (mean, 62.5 mm) claws. Strict adherence to the principles of functional trimming thus reduces the thickness of the sole, the length of the dorsal wall and the length and height of the bulb of the lateral claw. This suggests that the sole of the medial claw should be left an extra 3 mm thicker than previously recommended such that, after "levelling", the sole of the lateral claw remains thick enough to protect fully the corium and the claw retains a more normal shape.