Claw conformation of dairy heifers in two management systems.

A computerized conformation determination system was used to evaluate objectively claw conformation of dairy heifers in two management systems, i.e., housed indoors on concrete slats or out of doors in a dry lot. Examinations were made at 4-week intervals from 12-13 months of age until calving at 24-26 months. Overall, the angle of the dorsal border did not differ between front and hind claws. Length of the dorsal border, heel height, and toe:heel ratio were greater for front claws (P < 0.001). Hind claws were longer than front claws (P < 0.001), but front claws were wider (P < 0.001). On both front and hind limbs, lateral claws were wider than medial claws (P < 0.001). Angles of the dorsal border decreased, but lengths of the dorsal border and heel heights increased over time (P < 0.05). Significant differences in claw conformation were found between the two management groups. Heifers maintained out of doors had longer toes and wider lateral claws than heifers housed indoors (P < 0.05). At time of entry into the respective management group, no significant differences in claw traits were found between the two groups. At calving, however, out-door-housed heifers had hind claws with smaller dorsal angles and longer dorsal borders (P < 0.05).