Modern pig breeding companies mostly have a high sanitary status. Nevertheless, acquiring new breeding stockeven from companies with a high sanitary status always implies certain hygienic risks. Purchased breeding stock maycarry infectious agents which are not monitored on the farm of origin, or may become contaminated during transport.SPF or minimal disease breeder pigs have no acquired immunity against the infectious agents which they are guaran -teed free of. Thus on arrival at the farm of destination, they come in contact with some of these agents and may developserious disease symptoms. There fore, newly acquired breeding stock should go into quarantine on arrival, and the pre -mises used for the quarantine should be thoroughly cleaned and disinfected before arival.