Is the left forelimb preference indicative of a stressful situation in horses?

Evidence for behavioural and brain lateralisation is now widespread among the animal kingdom. Handedness, i.e. the preferential use of one hand at the population level, is a prominent manifestation of brain lateralisation in humans; however, lateralisation of limb use (pawedness) occurs in several mammals including both feral and domestic horses. We investigated limb preferences in 14 Quarter Horse during different motor tasks (walking, stepping on and off a step, truck loading and unloading). Population lateralisation was observed in two tasks: horses preferentially used their left forelimb during truck loading and stepping off a step. The results also revealed that horses showed higher scores for anxious behaviours during truck loading suggesting that the use of the left forelimb in this task may reflect the main role of the right hemisphere in control of behaviour during stressful situation.