In September 1986 an Integrated Quality Control Project (IQC) was started in the Netherlands. Over a period of 2 years a veterinary herd health scheme was applied to 21 growing and finishing pig herds. Information was collected concerning medical treatment, classified as group treatment and individual treatment, clinical observations, and housing factors. The main purpose of this project was to investigate relationships between pathological findings detected at the slaughterhouse and information gathered on the farm.