The information, ideas and opinions expressed are those of the author and do not necessarily represent those of the United States Department of Agriculture.

Treadmill Study Identifies Early Indicators of Subclinical Lameness

A treadmill study with five sound Thoroughbred horses was done to identify indicators of subclinical lameness. A flat steel shoe was modified to cause subclinical, subtle and mild lameness by applying a variable, controlled amount of sole pressure to both front and hind feet. Horses were examined at a walk and trot on the treadmill and video image analysis was used to identify signs of lameness.

As expected, symmetrical disturbances in movement of the head and croup were seen with subtle and mild lameness. That is, the head drops with placement of the sound limb and rises with loading of the lame limb; and the vertical displacement of the croup is greater on the affected side compared to the sound limb.

These changes were not seen with the very slight, subclinical lameness. In the forelimbs, the vertical lift-off acceleration of the forelimb decreased in response to the subclinical lameness. In the hindlimbs there was a posterior shift of the lift-off point of both hooves in response to the subclinical lameness.

While it seems unlikely these indicators could be detected during a visual lameness exam, they may be useful to detect early signs of subclinical lameness using a high speed treadmill. This could allow for earlier intervention and treatment of horses during the developmental stages of lameness.

—Orito K…