School of Animal Biology M085, Faculty of Natural & Agricultural Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia.
Animal. 2008 Nov;2(11):1645-50. doi: 10.1017/S1751731108002772.
In many equestrian pursuits such as dressage and show-jumping, it is important that the horse exhibits the same level of balance when ridden to the left as when ridden to the right in canter - that is, to show no motor bias. It is a long-held belief within such disciplines that to reduce bias that exists in horses and thus to enhance symmetry of performance to the left and right, the horse needs to be worked equally in both directions, although there is a lack of scientific evidence of this influencing bias. There also is little compelling evidence for either the existence or absence of motor bias in unridden (and therefore younger) or ridden (and therefore older) horses. In this study, we tested whether there was a difference in motor bias between unridden (n = 15) and ridden (n = 15) horses when their balance was challenged by cantering them in circles both to the left and to the right on the lunge. As indicators of a difference in balance between the left and right and thus as indicators of motor bias, we conducted three lunging tests - time spent in canter, whether the horse cantered on the correct lead and whether it became disunited. A grazing stance test, where the extended foreleg during grazing was recorded as the preferred forelimb, was also used to compare responses in a test where balance was not actively challenged, to the three lunging tests where balance was actively challenged. No bias was found in either the unridden or ridden groups when their balance was challenged, but ridden horses exhibited a motor bias in grazing stance - when their balance was not challenged. There was also a correlation between the responses in all three lunging tests, but none between the grazing stance test and any of the three lunging tests. We therefore conclude that neither ridden nor unridden horses are biased when their balance is challenged; thus it cannot be concluded that ambidextrous training affects an inherent bias, and that estimation of motor bias in horses is affected by the test conditions. Finally, if ridden horses are truly unbiased, strong human motor bias might be responsible for the common perception amongst riders that horses are biased.
在许多马术运动中，如盛装舞步和场地障碍赛，当马以跑步的方式在左侧和右侧骑行时，都表现出相同的平衡水平是很重要的，也就是说，没有运动偏向。在这些学科中，长期以来一直有一种观点认为，为了减少马身上存在的偏向，从而提高左右两侧的表现对称性，马需要在两个方向上同等地工作，尽管缺乏科学证据表明这会影响偏向。对于未经骑乘（因此更年轻）或骑乘（因此更老）的马是否存在运动偏向，也几乎没有确凿的证据。在这项研究中，我们测试了在左侧和右侧的跑步中，当马的平衡受到挑战时，未经骑乘的马（n=15）和骑乘的马（n=15）之间是否存在运动偏向的差异。作为平衡左右两侧差异的指标，因此作为运动偏向的指标，我们进行了三项跑步测试 - 跑步时间、马是否以正确的引导跑步以及是否分裂。我们还使用了一个放牧姿势测试，记录放牧期间伸出的前肢作为首选前肢，将其与三个主动挑战平衡的跑步测试进行比较，以比较在不主动挑战平衡的测试中的反应。无论是在未经骑乘的马还是骑乘的马中，当它们的平衡受到挑战时，都没有发现偏向，但骑乘的马在放牧姿势时表现出运动偏向 - 当它们的平衡没有受到挑战时。在所有三个跑步测试中都存在相关性，但在放牧姿势测试和三个跑步测试中的任何一个之间都没有相关性。因此，我们得出结论，无论是骑乘的还是未经骑乘的马，当它们的平衡受到挑战时，都没有偏向；因此，不能得出结论说双手训练会影响内在的偏向，而且马的运动偏向的估计受到测试条件的影响。最后，如果骑乘的马真的没有偏向，那么强烈的人类运动偏向可能是导致骑手普遍认为马有偏向的原因。
