Associations between limb lateralisation and hoof and limb asymmetries in adult horses

Calculated laterality indices were used to split 54 horses were in to left lateralised (22), right lateralised (24) (8 ambidextrous) groups. Widths of the top and base of the hoof were recorded and hoof spread calculated. Height of the elbow and carpometacarpal (CMC) joint from the ground and width of the third metacarpal were measured. Traits were compared against their contralateral pair in both lateralised groups, and against the same trait within the opposite lateralised group. Height of the carpometacarpal joint from the ground in the left lateralised group was longer in the right limb (P<0.01) and the toe angle in the right lateralised group was larger in the right foot. Previous studies have identified shorter left limbs in racehorses and have suggested that this asymmetry may support performance on a counter-clockwise track. The current findings may therefore draw a link between such limb asymmetries and left lateralisation.