Bovine lameness due to hoof and leg ailments causes significant economic losses to the dairy industry and it is an important animal welfare issue of great concern. Cow lameness necessitates medical treatment, reduces milk production, affects body condition, impairs reproduction performance, and impacts animal well being. Today, early detection of hoof and leg ailments is not a reality for most farmers as they can record an incidence only at the stage when the cow is visibly crippled. This book explains the development of a novel system designated as the Reaction Force Detection (RFD) system. The system has a walkthrough layout with an initial step-up and two parallel, left and right floor plates that are each supported by four load cells. When a cow walks through the system, the ground reaction forces are recorded as a function of time. An extensive lameness study was conducted for two years and a statistical model using logistic regression was developed. This model resulted in a Lameness Index Predicting Function (LIPF) which predicts the Lameness Index (LI) of hind limbs. Currently, the RFD system is marketed globally as StepMetrix by BouMatic.