Bovine lameness caused by hoof and leg ailments is a costly problem for the dairy farmer and an important animal
welfare issue. Cow lameness necessitates medical treatment, can reduce milk production, often results in decreased body
condition, can impair reproductive performance, and impacts animal well being. It was hypothesized that measurements of
vertical ground reaction forces as animals walk over a force–plate system could provide the basis for detecting lameness. A
system based on this principle, designated the Reaction Force Detection (RFD) system, was developed. The system consists
of two parallel, left and right, floor plates that are each supported by four single–axis load cells. When a cow walks through
the system, the load cell reaction forces are recorded as electric signals that change over time. These signals are used to
calculate the magnitude and position of a single equivalent reaction force for each plate. When a single limb is on a plate,
the calculated value represents the position and reaction force of that limb. Examination of calculated values over time allows
leg movement characteristics to be reconstructed, thus allowing measured reaction forces to be associated with specific limbs.
Additionally, the system provides measurements of body weight and walking speed. Tests using three sound and three lame
cows demonstrated that lame cows can be recognized and effected limbs can be identified.