“Wither drop” reveals asymmetry in horses

Move over gait and saddle fit — researchers have discovered a new method of assessing asymmetry in horses, and it’s proving very effective!

In a recent study published by PLOS One, researchers discovered that some horses drop their withers further when stepping with a certain foreleg. Typically, when assessing the symmetry of a horse, equestrians assess gait and saddle fit. But this new evaluation of unevenness looks at up-and-down wither movement (as opposed to side-to-side), which makes assessing lateral asymmetries – and ultimately striving for straightness – much easier.

“This is likely of benefit both for the trainer who tries to increase symmetry while training the horse, as well as for the clinician trying to determine if a slight asymmetry is lameness or ‘only laterality’,” says Dr. Agneta Egenvall, a professor in veterinary epidemiology at the Swedish University of Agricultural Sciences.

Egenvall and her team used treadmills to measure wither drop in seven sound dressage horses. They predicted that wither drop could be related to the length of the horse’s forelimb stride, or the distance between the forelimbs. But it could be the result of a variety of other factors. “The asymmetry may well stem from more central parts of the body, perhaps stiffness in the shoulder area or the croup, or from a difference in stiffness or movement ranges of the lower limbs, or even hoof shape or mechanics.”