In modern large-scale pig production, first-rate hygienic conditions are necessary to avoid outbreaks of diseases and promote and maintain a good biosecurity, However, evaluation of pen hygiene is highly subjective. The project aims to adapt and evaluate a new method for the standardised measure of the "infectious load" on the pig pen floor, and evaluate the impact of various floor structures and cleaning and disinfection protocols. In WP 1) the retrieval rate following sampling will be evaluated by applying a standardized amount of bacteria on a completely clean floor structure suitable for pigs. In WP 2) possible residual infections will be measured on a similar floor in an ongoing pig production. Three cleaning protocols will be evaluated. In WP 3) the effect of selected, commonly used cleaning and disinfection protocols, and the interference from the floor structures on the pen hygiene, will be evaluated in a 3 x 3 design.