Heart-bar horseshoes that incorporate an adjustable pressure screw are used as a reversible model of hoof pain for experimental studies of anti-inflammatory medications. In this trial, researchers applied heart-bar shoes to five mares. They measured three biochemical markers for inflammation in the bloodstream, as well as dorsal coronary band temperature, before and after the shoes were adjusted to create a Grade 4 lameness (obvious at a walk, AAEP scale 0-5) to determine the role inflammation plays in this model of hoof pain.