Equine Lameness Score Calculator

Lameness grading in horses is inherently subjective, so this calculator turns four separate clinical observations into a single reproducible number on the American Association of Equine Practitioners' (AAEP) standard 0-5 scale (0 = sound, 5 = non-weight-bearing) -- the same scale used and documented in peer-reviewed equine lameness research, such as Keegan et al.'s 2010 study on the repeatability of subjective lameness scoring in Equine Veterinary Journal. It weights the four inputs by how reliably each one predicts true lameness severity: head bob or hip hike carries the heaviest weight (0.4), since that visible asymmetry is the classic hallmark clinicians look for first; stride length asymmetry is next (0.3); flexion test response (0.2) and hoof tester response (0.1) round out the composite, each scored on its own 0-3 or 0-4 severity scale. The weighted sum produces a raw composite score, which is then scaled by 1.25 and rounded to map onto the AAEP's 0-5 grade. From there the calculator also estimates whether the pattern of responses points toward soft-tissue/joint origin (positive flexion test, low hoof tester response) versus hoof/foot pathology (the reverse pattern) — these are directional indices between 0 and 1, not a diagnosis, since flexion and hoof tester findings can both be positive in mixed presentations.

A rest-days recommendation ladders up with grade severity, from no restriction at grades 0-1 to 60 days and veterinary emergency evaluation at grade 5. An "assessment agreement" percentage flags when the four component scores disagree sharply with each other (e.g., severe head bob but no flexion response), which is worth flagging to the examining vet since inconsistent findings across parameters can indicate a more complex or multifactorial lameness rather than a single clean cause. The Affected limb selection is recorded for context (it labels whether the head-bob input reflects a forelimb head bob or a hindlimb hip hike) but is not itself read by the scoring formula and does not change the composite score or any other output. This tool aids clinical scoring; it is not a substitute for hands-on examination and does not diagnose the underlying condition.