1. Performance in Equestrian Sport Group
A preliminary investigation which indicates the use of forelimb data has limitations in accurately determining laterality in horses
L Greening1*, L. Palmer1 and T. Bye2
1Hartpury University Centre, Gloucestershire, UK*
2Bishop Burton College, East Yorkshire, UK
INTRODUCTION: Side preference is suggested to link with cognitive bias and the phenomenon of laterality is proven in a range of species, including the horse (Murphy et al., 2005). Motor lateralisation refers to directional bias; in equine research this has been measured using the favoured forelimb during the initiation of movement or the advanced forelimb during grazing (McGreevy and Thompson, 2006; McGreevy and Rogers, 2005). Little research exists to validate the links between forelimb observations and side preference, for example the hindlimb in most cases initiates movement. Two preliminary studies were conducted; the first aimed to identify whether fore and hindlimb preference matched, the second aimed to consider whether kinematic measurements differ between the preferred and non preferred sides, allocated in relation to forelimb preference.
STUDY TWO METHOD: Four horses (age mean + s.d years) were observed whilst eating a forage ration from the floor to establish limb preference using the laterality equation from trial one; these individuals underwent a conformational assessment to discount participants with conformational asymmetries (Mawdsley et al., 1996). Skin markers were attached to correspond with the major joints of the appendicular skeleton. Horses were trotted in-hand past a Casio EX-ZR1000 camera located 10m away perpendicular to the plane of motion. Three passes in each direction were made for each horse, with the handler on the side furthest from the camera. Kinematic measurements were taken using Quintic Biomechanics v26 of the following traits; stride length, peak tarsal flexion angle, forelimb protraction (measured as largest angle of proximal forelimb to the vertical), duty factor and peak fetlock extension angle (during the stance phase). Comparisons were made between the preferred and non-preferred side.
STUDY ONE METHOD: Six horses (various breed and sex, age mean + s.d years) were released ten consecutive times to navigate towards a feed bucket in an enclosed arena. Horses were stood square at the starting point. An additional operator stood directly in front of the horse, turned 180° upon release and walked directly towards the feed bucket. Frequency data were collected from observations of the hind limb used to initiate movement and fore limb advancement. Laterality indices were calculated (McGreevy and Rogers, 2005).
STUDY TWO RESULTS: Mean kinematic measurements were taken from the three repetitions on each side (see table below). Individual asymmetries were noted in all movement parameters (Fig. 2 shows example) but no relationship was observed between these and the advanced forelimb used to determine laterality. Statistical analysis was not possible due to small sample population.
Table 1: Means of kinematic measurements for all horses
Figure 2: Mean forelimb protraction angles in the trot for each individual on the sides on the preferred and non-preferred forelimbs
Preferred Side
Non-preferred Side
Stride Length (m)
2.46
2.43
Stride Duration (s)
0.73
0.74
HL Duty Factor
0.39
0.40
Peak Tarsal Flexion°
116°
114°
HL Fetlock Extension°
126°
127°
FL Protraction°
47°
45°
FL Fetlock Extension°
124°
123°
STUDY ONE RESULTS: The left hindlimb initiated movement during 43% of observations. Laterality index for hindlimb indicated a right-side preference (13.33). The left forelimb was advanced whilst eating from the bucket for 51% of observations. Laterality index for forelimb indicated a slight left-side preference (-1.69) (Fig. 1). Statistical analysis was not possible due to small sample population.
Figure 1: Hindlimb initiation relationship to forelimb advancement frequency
CONCLUSIONS: Results from these preliminary studies suggest that hindlimb preference is not matched by forelimb preference. Additionally forelimb preference does not appear to impact on locomotion in the trot. Further study is required to determine links with lateralisation, where a better understanding of individual preferences for directional and cognitive bias may inform equine training.
REFERENCES: Mawdsley et al. (1996) Linear assessment of the Thoroughbred horse: An approach to conformation evaluation. Eq Vet J 28(6) pp461-7; McGreevy, P.D. and Rogers, L.J. (2005) Motor and sensory laterality in thoroughbred horses. Appd Anim Behav Sci 92 pp337–52; McGreevy, P.D. and Thomson, P.C. (2006) Differences in motor laterality in breeds of performance horse. Appd Anim Behav Sci 99 pp ; Murphy, J., Sutherland, A. and Arkins, S. (2005) Idiosyncratic motor laterality in the horse. Appd Anim Behav Sci 91 pp
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Performance in Equestrian Sport Group