In intensive piggeries, sound hygiene can minimise disease problems and maximise production. A good standard of hygiene depends largely on the design of the piggery, management, routine cleaning and disinfection, and good housekeeping. Unhygienic conditions reduce the pig's resistance to infection allowing disease problems to flourish.
Disinfection without cleaning first is a waste of money. Cleaning is the management of dirt that can be seen partially: to separate and remove this dirt from a surface, through water and a detergent. In other words, to make the surface as free as possible from organic soil, that would impede the disinfectant to reach the surface.
Very important is the "operational bio-security" that refers to managerial hygiene practices or the management of the 3 P's : Products, Procedures and People.